ADOPTS WITH AMENDMENTS:

NFPA 70, 2017

Heads up: There are no amended sections in this chapter.

Part I General

700.1 Scope

AMENDMENT
This section has been amended at the state or city level.
The purpose of this article is to provide details for installation of required exit and emergency illumination systems in all buildings, new and existing.

The provisions of Article 700 are intended to provide a reasonably reliable alternate source of electrical power upon the failure of the normal source of supply. It is impossible to list all of the various means of accomplishing the desired results. Article 700 is intended to set a minimum standard for such installations.

Informational Note No. 1: For further information regarding wiring and installation of emergency systems in health care facilities, see Article 517.

Informational Note No. 2: For further information regarding performance and maintenance of emergency systems in health care facilities, see NFPA 99-2015, Health Care Facilities Code.

Informational Note No. 3: For specification of locations where emergency lighting is considered essential to life safety, see NFPA 101-2015, Life Safety Code.

Informational Note No. 4: For further information regarding performance of emergency and standby power systems, see NFPA 110-2013, Standard for Emergency and Standby Power Systems.

700.2 Definitions

AMENDMENT
This section has been amended at the state or city level.
Auxiliary Source of Current Supply. The auxiliary source of current supply shall be another independent source of current supply, isolated from the normal source, either from the utility, an on-site generator, an inverter, or unit batteries where allowed in this article.

Emergency Lighting (Illumination) Systems. Emergency lighting systems shall be lighting systems required by this chapter which supplement the general lighting system.

Exit Lighting Systems. Exit lighting systems shall be those electrical systems which supply electricity to required exit, directional, stairway and fire escape signs.

Informational Note: See Sections 13-160-700 through 13-160-820 of the Chicago Building Code for location and type.

Emergency Systems. Emergency systems are intended to automatically supply illumination, power, or both, to designated areas and equipment in the event of failure of the normal supply or in the event of accident to elements of a system intended to supply, distribute, and control power and illumination essential for safety to human life.

Final Reserve Source of Current Supply. The final reserve source of current supply shall be an approved battery source, on-site generator installed in accordance with Article 701, or an approved on-site inverter system.

Normal Source of Current Supply. The normal source of current supply is that supply which furnishes electrical energy for general illumination and power purposes.

Relay, Automatic Load Control. A device used to set normally dimmed or normally-off switched emergency lighting equipment to full power illumination levels in the event of a loss of the normal supply by bypassing the dimming/switching controls, and to return the emergency lighting equipment to normal status when the device senses the normal supply has been restored.

Informational Note: See ANSI/UL 924, Emergency Lighting and Power Equipment, for the requirements covering automatic load control relays.

700.3 Tests and Maintenance

AMENDMENT
This section has been amended at the state or city level.

(A) Conduct or Witness Test

AMENDMENT
This section has been amended at the state or city level.

(B) Tested Periodically

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This section has been amended at the state or city level.

(C) Maintenance

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(D) Written Record

AMENDMENT
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(E) Testing Under Load

AMENDMENT
This section has been amended at the state or city level.

(F) Temporary Source of Power for Maintenance or Repair of the Alternate Source of Power

AMENDMENT
This section has been amended at the state or city level.

700.3 General

AMENDMENT
This section has been amended at the state or city level.
The provisions of this article shall be in addition to or amendatory of those set forth in Chapters 1 through 4 of this Code. Emergency and exit lighting systems shall not be intermingled with any other wiring system in the building except as otherwise allowed in this article.

700.4 Capacity

AMENDMENT
This section has been amended at the state or city level.

(A) Capacity and Rating

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This section has been amended at the state or city level.

(B) Selective Load Pickup, Load Shedding, and Peak Load Shaving

AMENDMENT
This section has been amended at the state or city level.

700.4 Plan Submittal Procedure

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This section has been amended at the state or city level.
No work shall start on the exit and emergency lighting systems before approved by the authority having jurisdiction.

In addition to any other information required by the authority having jurisdiction, the plans shall indicate:
  1. The location of all exit and emergency lights on scaled floor plans of a scale not less than 1/8 in. = 1 ft.
  2. The location of all normal lights in areas with exit and emergency lights.
  3. A single line drawing of the emergency service and distribution showing sizes of conduit, conductors, switches, and overcurrent devices.
  4. Connected load of all branch circuit panels.
  5. Information relative to generators as required in Section 701.9.
Exception No. 1: In new buildings, when the first tenant is entering a space, it shall not be necessary to submit the information required in (c) through (e) above, provided each plan indicates the reviewed plan number on which the information was previously submitted.

Exception No. 2: It shall be the responsibility of the plan applicant to determine the adequacy of an existing emergency service and distribution. The details of this service and distribution, in (c) above, need not be shown when it is stated by the submitter that the existing emergency system is in conformance with this chapter. However, the drawings shall indicate the measured connected load for the affected emergency branch circuit panels, and the connected load for all additional circuits being altered or installed.

Part II Emergency System Requirements

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This section has been amended at the state or city level.

700.5 Type of Emergency Systems Required

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This section has been amended at the state or city level.
The type of emergency system (I, II, or III) provided in buildings shall be as indicated in Table 700.5, except an existing occupancy with a type III or better system permitted under an earlier version of this Code may continue to use that system. All required emergency lights, exit, directional, stairway and fire escape signs in these buildings shall be supplied from the emergency system as required in this Article.
Table 700.5 Emergency System Type Required — By Use6

Occupancy Classification*

Additional Criteria

System Type

I

II

III

A-1, A-3, A-4, A-5

Occupant load: 50 to 99    

X

Occupant load: 100 to 300  

X

 
Occupant load: more than 300; entirely on level of exit discharge  

X

 
Occupant load: more than 300; on level other than level of exit discharge

X

   
100 to 300 fixed seats5  

X

 
More than 300 fixed seats5

X

   

B

Ambulatory care facilities (see Article 517)  

X2

 

A-2, B, M, F, S

Gross floor area of 10,000 square feet or more    

X

Areas on level other than level of exit discharge  

X

 

E-1

100 or fewer students in building    

X

More than 100 students in building  

X

 
Auditoriums with fixed seats

See Group A

E-2

All    

X

I-1, condition 1

All

See Group R

I-1, condition 2
 Two or more stories or more than 20 residents  

X

 
I-2, condition 1
All  

X2

 
I-2, condition 2
All

X

   

I-3

More than 20 detainees or located on level other than level of exit discharge  

X

 

I-4

More than 20 care recipients or located on level other than level of exit discharge
 

 X

 

R-1 or R-2

Single-room occupancy (see Chapter 17-17 of Chicago Zoning Ordinance)
 

X

 

R-1

Two or more stories or more than 20 guest rooms
 

X

 

R-2

 

Five or more dwelling units (see Articles 560 and 570)
 

 

X

Congregate living facilities; two or more stories or more than 20 residents
 

 

X

R-3, R-4

Two or more stories or more than 20 residents
 

 

X


* See Chapter 14B-3 of the Chicago Building Code

Notes to Table 700.5
  1. All existing and newly constructed high-rise buildings containing dwelling units shall provide an approved, on-site auxiliary source of current supply for the egress lighting and exit signs.
  2. The second source of current supply shall be an on-site generator or a battery system.
  3. See 700.30.
  4. The auxiliary source of current supply shall be from an on-site diesel generator. This shall apply to all buildings 91 m (300 ft) and over unless the building requires a System I under other uses.
  5. Any building or space where fixed seating is provided for use during any performance or meeting shall be provided with a System I emergency system where having capacity for more than 300 persons and shall be provided with aisle lighting where having capacity for more than 150 persons. In buildings with multiple spaces containing fixed seats, the classification of the emergency system shall be based on the total number of fixed seats in the building. The aisle lighting requirement shall be based on the number of fixed seats in each space.
  6. Where System III is required, a System I or II may be installed. Where System II is required, a System I may be installed.

700.6 Illumination Required

AMENDMENT
This section has been amended at the state or city level.

(A) General

AMENDMENT
This section has been amended at the state or city level.
In general, every portion of a building devoted to the use or accommodation of occupants, including all assembly rooms, all means of egress leading to the streets, open courts, corridors, stairways, exits, emergency exit stairways, or any other part of the building used by occupants, shall be well illuminated in accordance with requirements for general illumination.

(B) Emergency

AMENDMENT
This section has been amended at the state or city level.
In addition, there shall be emergency illumination as required by 700.11 to enable occupants to evacuate the building without difficulty upon failure of the general illumination system. The emergency illumination shall be available within the time required for the application but not to exceed 10 seconds.

The required emergency lighting and exit lighting systems shall be functional whenever the building is occupied.

Emergency lighting systems shall be designed and installed so that the failure of any individual lighting element, such as the burning out of a light bulb, cannot leave in total darkness any space that requires emergency illumination.
Exception: Except as allowed in 700.66(C)(6).

Where high-intensity discharge lighting such as high- and low-pressure sodium, mercury vapor, and metal halide is used as the sole source of normal illumination, the emergency lighting system shall be required to operate until normal illumination has been restored.

Exception No. 1: In residential buildings, emergency fixtures which illuminate areas of a building with unobstructed natural illumination shall be permitted to be controlled by photocell(s). The photocell shall be permitted to control multiple fixtures as long as the photocell and the fixtures are located in the area with the natural illumination insuring that the illumination required in 700.11 is present in the space at all times.

Exception No. 2: In buildings with not more than 12 dwelling units and not greater than 4 stories above grade, with open exterior means of egress, emergency illumination shall not be required on the exterior portion of the means of egress, where sufficient general illumination is present. Similar buildings with more than 12 dwelling units or greater than four stories above grade may only omit exterior emergency illumination with special permission.

(C) Source

AMENDMENT
This section has been amended at the state or city level.
All buildings requiring emergency illumination as stated in 700.5 shall not rely solely upon electric utility power as a source.

Such buildings shall have an emergency system as called for in Table 700.5. In addition, if the auxiliary source is one of the sources listed in 700.33(A) through (G), an additional on-site source of power for the emergency lighting and exit lighting systems shall be required. This source of power shall be permitted to be:
  1. A generator in conformance with 700.33(H)
  2. An inverter system installed in accordance with 700.33(I)
  3. Unit batteries conforming to 700.30(C), 700.43, and 700.44
All unit battery equipment shall comply with 700.66.

700.7 Expositions Halls, Schools, and Theaters

AMENDMENT
This section has been amended at the state or city level.

(A) General

AMENDMENT
This section has been amended at the state or city level.
In the auditorium of a theater, school, or exposition building there shall be a sufficient number of emergency lighting outlets properly distributed to provide one foot-candle of illumination at all points on the floor area. In all parts of the building used by the occupants, alternate emergency lighting outlets shall be supplied through separate circuits.

(B) Aisle Lighting

AMENDMENT
This section has been amended at the state or city level.
Additional lighting outlets of an approved type on the emergency lighting system shall be placed in the aisles of an auditorium with fixed seats, as follows:
  1. Where the aisles are smooth running ramps, aisle lighting outlets shall be placed at a minimum of every third row of seats.
  2. In aisles in which there are steps, aisle lighting outlets shall be placed so as to illuminate each step.
  3. Aisle lighting outlets on the opposite sides of an aisle shall be supplied through separate branch circuits.
  4. Where aisle lighting outlets are only on one side of the aisle, alternate lights shall be on separate branch circuits.
  5. Other listed systems which provide equivalent illumination shall be permitted. Such systems shall be supplied by more than one circuit so that the loss of a circuit would not leave the aisle or steps completely without illumination.
Exception No. 1: Auditoriums with a capacity for 150 or fewer persons shall not be required to have additional aisle lighting outlets where there is an unobstructed direct line of sight to identified exits or exit corridors and all other required emergency illumination is present.

Exception No. 2: Where the fixed seating is of the type that can be reassembled for various layouts and the theater intends to change the layout for various performances, a flexible wiring method for aisle lighting shall be permitted where:
  1. The aisle lighting system complies with 700.7(B)
  2. All associated aisle lighting cords are listed as "extra-hard usage"
  3. All associated aisle lighting cord plug and receptacle connections are twist lock
  4. All associated aisle lighting cords are of the minimum length needed for flexibility
  5. Additional strain relief is provided around all associated aisle lighting cord and receptacle connections
  6. The point of connection to the permanent emergency system is visibly identified and of the type that will not accept standard straight blade plugs
A permit and inspection are required for all reconfiguration of seating prior to use.

Informational Note: This flexible allowance for aisle lighting is not intended and shall not be permitted as a permanent wiring method.

(C) Additional Locations

AMENDMENT
This section has been amended at the state or city level.
In addition to requirements of 700.7(A), emergency lighting shall be provided:
  1. In the projection booth
  2. At the lighting service equipment
  3. At the stage lighting control equipment
  4. In the room that contains the emergency lighting generator or the batteries

700.8 Hospitals

AMENDMENT
This section has been amended at the state or city level.
Where a System I is required, permanently connected emergency lights and the ungrounded electrical system (if installed) shall be supplied from the final reserve source of current supply in addition to the general lighting in all critical and special care areas. The final reserve source of current supply shall be a diesel generator in conformance with 700.33(H).

The emergency lights shall be adequate to illuminate these rooms for their normal use, and shall be completely separate from the general wiring systems. Switches to turn emergency lights "OFF" when a room is not in use shall be permitted to be installed for each individual room.

Informational Note: See Article 517Health Care Facilities.

700.9 Tenant Spaces in Multi-Use or Multi-Space Buildings

AMENDMENT
This section has been amended at the state or city level.
Emergency lighting shall be provided within a tenant space, other than a dwelling unit, exceeding 93 m2 (1,000 ft2) in any building in which emergency lighting is required.

700.10 Emergency Lighting for Passenger Elevators

AMENDMENT
This section has been amended at the state or city level.
Unit batteries shall be provided for standby emergency illumination in the elevator car. Immediately after normal car lighting power fails, emergency lighting shall be provided in all elevators in accordance with the Chicago Building Code.

Informational Note: See the Safety Code for Elevators and Escalators, ASME A17.1 § 2.14.7.1 for further information.

700.11 Intensity of Emergency Illumination

AMENDMENT
This section has been amended at the state or city level.
In general the required emergency illumination shall provide not less than one foot-candle of illumination on all points of all required areas.

Exception No. 1: As allowed by 13-160-670 or 13-160-680. Upon failure of the normal lighting system the emergency lighting shall be restored to full brilliance.

Exception No. 2: Where dimming of the emergency lighting below one foot-candle is required, the following shall apply:
  1. Special permission shall be required.
  2. Upon failure of the normal lighting system the emergency lighting shall be restored to full brilliance.
  3. The emergency lighting shall not be dimmed below 1/2 foot-candle.

700.12 Capacity of Emergency System

AMENDMENT
This section has been amended at the state or city level.
The exit and emergency system, service and feeders shall have a minimum capacity of 0.1 watts per square foot, based on the total square foot area of the building.

700.20 System I

AMENDMENT
This section has been amended at the state or city level.

(A) Sources of Supply

AMENDMENT
This section has been amended at the state or city level.
System I shall consist of three sources of electrical energy supply as follows:
  1. The normal source of current supply
  2. An auxiliary source of current supply totally separate from the normal source
  3. A final reserve source of current supply from batteries, from an on-site generator(s) in conformance with Article 701, or from an on-site inverter

(B) Sequence

AMENDMENT
This section has been amended at the state or city level.
System I shall have the following sequence of current supply to the emergency lights and exit signs:
  1. The normal source of current supply
  2. The auxiliary source of current supply upon failure of the normal source of current supply
  3. The final reserve source of current supply upon failure of both the normal and the auxiliary sources of current supply
Informational Note: See Parts III and IV of this Article.
Figure 700.20 Typical System I Emergency System

700.21 System II

AMENDMENT
This section has been amended at the state or city level.

(A) Sources of Supply

AMENDMENT
This section has been amended at the state or city level.
System II shall consist of two sources of electrical energy supply as follows:
  1. The normal source of current supply
  2. The auxiliary source of current supply

(B) Sequence

AMENDMENT
This section has been amended at the state or city level.
System II shall have the following sequence of current supply to the emergency lights and exit signs:
  1. The normal source of current supply
  2. The auxiliary or final reserve source of current supply upon failure of the normal current supply.
  3. For emergency illumination and exit sign purposes, if the auxiliary source of current supply is not one of the sources listed in 700.33(H), 700.33(I), 700.30(C), or 700.43 an additional source which complies with 700.6(C) shall be provided.
Informational Note: See Figure 700.21.

Figure 700.21 Typical of Either System II or System III Emergency Systems

700.22 System III

AMENDMENT
This section has been amended at the state or city level.
System III shall consist of two sources of current supply as follows:
  1. The normal source of current supply to the structure which shall provide for the general illumination
  2. The second source of current supply shall provide electrical current supply for the emergency lighting and exit lighting systems and shall be either an auxiliary source in accordance with 700.33(H) or 700.33(I), or approved unit battery equipment in accordance with 700.43
  3. A transfer switch shall not be required.
Informational Note: See Figure 700.21.

700.5700.23 Transfer Equipment

AMENDMENT
This section has been amended at the state or city level.
Transfer equipment, including automatic transfer switches, shall be automatic, identified for emergency use, and approved by the authority having jurisdiction. Transfer equipment shall be designed and installed to prevent the inadvertent interconnection of normal and emergency sources of supply in any operation of the transfer equipment. Transfer equipment and electric power production systems installed to permit operation in parallel with the normal source shall meet the requirements of Article 705.
Means shall be permitted to bypass and isolate the transfer equipment. Where bypass isolation switches are used, inadvertent parallel operation shall be avoided.

(C) Automatic Transfer Switches

AMENDMENT
This section has been amended at the state or city level.
Automatic transfer switches shall be electrically operated and mechanically held. Automatic transfer switches, rated 1,000 VAC and below, shall be listed for emergency system use.

(D) Use

AMENDMENT
This section has been amended at the state or city level.
Transfer equipment for emergency illumination and exit signs shall supply only those loads.

(E) Documentation

AMENDMENT
This section has been amended at the state or city level.
The short-circuit current rating of the transfer equipment, based upon the specific overcurrent protection device type and settings protecting the transfer equipment, shall be field marked on the exterior of the transfer equipment.

700.6700.24 Signals

AMENDMENT
This section has been amended at the state or city level.
Audible and visual signal devices shall be provided, where practicable, for the purpose described in 700.24(A) through (F).
To indicate malfunction of the emergency source.
To indicate that the battery is carrying load.
To indicate that the battery charger is not functioning.

(D) Ground Fault

AMENDMENT
This section has been amended at the state or city level.
To indicate a ground fault in solidly grounded wye emergency systems of more than 150 volts to ground and circuit-protective devices rated 1,000 amperes or more. The sensor for the ground-fault signal devices shall be located at, or ahead of, the main system disconnecting means for the emergency source, and the maximum setting of the signal devices shall be for a ground-fault current of 1200 amperes. Instructions on the course of action to be taken in event of indicated ground fault shall be located at or near the sensor location.

(E) Bypass Isolation

AMENDMENT
This section has been amended at the state or city level.
To indicate that the bypass isolation is in the bypass position.

(F) Remote Annunciation

AMENDMENT
This section has been amended at the state or city level.
Remote audible and visual annunciation of the transfer switch(es) at a common central manned location shall be installed where the transfer switches are not installed in a location that is manned at all times when the building is open.

Informational Note: For signals for generator sets, see NFPA 110-2013, Standard for Emergency and Standby Power Systems.

700.7700.25 Signs

AMENDMENT
This section has been amended at the state or city level.

(A) Emergency Sources

AMENDMENT
This section has been amended at the state or city level.
A sign shall be placed at the service-entrance equipment, indicating type and location of each on-site emergency power source.

Exception: A sign shall not be required for individual unit equipment as specified in 700.43.

Where removal of a grounding or bonding connection in normal power source equipment interrupts the grounding electrode conductor connection to the alternate power source(s) grounded conductor, a warning sign shall be installed at the normal power source equipment stating:

WARNING
SHOCK HAZARD EXISTS IF GROUNDING ELECTRODE CONDUCTOR OR BONDING JUMPER CONNECTION IN THIS EQUIPMENT IS REMOVED WHILE ALTERNATE SOURCE(S) IS ENERGIZED.

The warning sign(s) or label(s) shall comply with 110.21(B).

700.8700.26 Surge Protection

AMENDMENT
This section has been amended at the state or city level.
A listed SPD shall be installed in or on all emergency systems switchboard and panelboards.

700.28 Selective Coordination

AMENDMENT
This section has been amended at the state or city level.
Emergency system(s) overcurrent devices shall be selectively coordinated with all supply-side overcurrent protective devices.

Selective coordination shall be selected by a licensed professional engineer or other qualified persons engaged primarily in the design, installation, or maintenance of electrical systems. The selection shall be documented and made available to those authorized to design, install, inspect, maintain, and operate the system.

700.30 High Rise Buildings

AMENDMENT
This section has been amended at the state or city level.

(A) Under 300 Feet in Height

AMENDMENT
This section has been amended at the state or city level.
In high rise buildings under 91 m (300 ft) in height, the auxiliary source of current supply to the emergency lighting and exit lighting systems shall be one of the following:
  1. An on-site generator
  2. A battery inverter system in conformance with 700.33(I)
  3. A completely independent utility company primary and either or both:
    1. An on-site generator in conformance with Article 701
    2. A battery inverter system in conformance with 700.33(I)
Exception: Existing high rise buildings containing dwelling units may use unit battery equipment in conformance with the exception to 700.30(C) or an approved battery inverter system with a minimum capacity of 90 minutes.

(B) 300 Feet in Height and Over

AMENDMENT
This section has been amended at the state or city level.
In buildings 300 feet in height or greater, the auxiliary source of current supply to the emergency lighting and exit lighting systems shall be from an on-site diesel generator in conformance with Article 701.

(C) Dwelling Type Uses

AMENDMENT
This section has been amended at the state or city level.
New and existing high rise buildings that contain dwelling units shall have an on-site source of supply, independent from the utility source, for the emergency lighting and exit lighting systems. The on-site source of supply shall be a generator in conformance with 700.33(H) or an inverter system in conformance with 700.33(I).

Generators shall conform to the following:
  1. High rise buildings under 91 m (300 ft) shall be permitted to have natural gas or diesel fuel as supply and shall comply with Article 701.
  2. High rise buildings 91 m (300 ft) and over shall be required to have diesel fuel as the supply and shall comply with Article 701.
Exception No.1: Approved unit battery equipment shall be permitted to supply the emergency lighting and exit lighting systems in existing buildings under 91 m (300 ft) that contain dwelling units, provided they comply with 700.43 and 700.66(C). Buildings undergoing 60% or more renovation of interior spaces or the electrical system shall not be included in this exception.

Exception No. 2: Approved unit battery equipment shall be permitted for the emergency illumination and exit signs in existing buildings 91 m (300 ft) and over that contain dwelling units provided that such equipment was installed prior to February 7, 2000.


Informational Note No. 1: The above exceptions do not relieve other Code requirements regarding elevators, sump pumps, fire alarms systems, etc.

Informational Note No. 2: See Section 13-76-080 or 14B-4-403 of the Chicago Building Code.


All paths of egress that serve the dwelling units, or are common to both the dwelling units and other spaces in mixed occupancy buildings, shall meet the emergency illumination requirements of this subsection.

Part III Approved Auxiliary Sources

AMENDMENT
This section has been amended at the state or city level.

700.33 Approved Auxiliary Sources

AMENDMENT
This section has been amended at the state or city level.
The auxiliary source of current supply for all emergency system installations shall comply with any one of the following conditions:

(A) Isolated Plant

AMENDMENT
This section has been amended at the state or city level.
When the normal source of current supply is an isolated plant, the auxiliary source of current supply shall be from an approved overhead or underground service from a utility company.

(B) Overhead Service

AMENDMENT
This section has been amended at the state or city level.
The auxiliary source of current supply shall be permitted to be from the same source of current supply as the normal source of current supply provided:
  1. The normal source of current supply is an overhead service from the utility company and no other utility source is available.
  2. The auxiliary source of current supply is from a different pole and is by separate drop, service conduit, and equipment as widely separated from the normal source of current supply as physical conditions permit.

(C) Separate Transformers

AMENDMENT
This section has been amended at the state or city level.
When the normal lighting and power supply is alternating current from separate transformers:
  1. The auxiliary source of current supply shall be permitted to be from an approved transformer or transformers within the building and supplied from the power service.
  2. The current supply to the transfer switch shall be taken from the first distribution point on the load side of the light and power service switches.

(D) Underground Network System

AMENDMENT
This section has been amended at the state or city level.
Where the source of current supply is common to both light and power and is a utility-supplied underground, 3 phase, network system fed from two or more generating or substations, the auxiliary source of current supply shall be permitted to be a separate service from the utility supplied underground network system. A transfer switch shall not be required.

(E) Spot Network

AMENDMENT
This section has been amended at the state or city level.
The auxiliary source of current supply shall be permitted to be a separate service where the source of current supply is common to both light and power, and is what is known as a "spot network" having:
  1. Two separate primaries
  2. Two utility company transformers
  3. Utility switchgear necessary to accomplish fully automatic switching in both directions. A transfer switch shall not be required.

(F) Common Source

AMENDMENT
This section has been amended at the state or city level.
Where the source of current supply is common to both light and power and consists of a single utility company primary supplying one or more transformers located on a pole structure or on a pad outside of the building being served, the auxiliary source of current supply shall be taken from the secondary side of the transformer or transformers through a separate set of service entrance conductors, a separate service conduit, a service switch and a ground. A transfer switch shall be required.

(G) Building Vault

AMENDMENT
This section has been amended at the state or city level.
Where the source of current supply is in a vault located inside of the building being served and the secondary leads are as short as possible, the emergency auxiliary source of current supply shall be permitted to be a separate service from the vault. A transfer switch shall not be required.

(H) Approved Generator

AMENDMENT
This section has been amended at the state or city level.
Where the normal source of current supply is an approved utility company service, the auxiliary source of current supply shall be permitted to be an on-site generator installed in accordance with Article 701.

(I) Inverter System

AMENDMENT
This section has been amended at the state or city level.
Where the normal source of current supply is an approved utility company service, the auxiliary source of current supply shall be permitted to be an approved on-site inverter complying with the following:
  1. The inverter system shall be listed for emergency system use and have battery capacity to power the entire emergency lighting and exit sign system as follows:
    1. In high rise buildings as required by Section 700.30 for a period of four hours
    2. In places of assembly with an occupancy greater than 1,000 persons for a period of four hours
    3. In all other occupancies for a period of ninety minutes.
  2. The inverter system shall be tested at full load for the rated time at least once per year.
  3. This annual test shall be witnessed by the authority having jurisdiction, and the required inspection fee for this test shall be paid.
Informational Note: Note that utility supplied auxiliary sources as listed in 700.33(A) through (G) above shall not solely satisfy the emergency illumination requirements of this article. See 700.6(C).

700.43 Approved Unit Battery Equipment

AMENDMENT
This section has been amended at the state or city level.

(A) Approved Unit Battery Equipment

AMENDMENT
This section has been amended at the state or city level.
Approved unit battery equipment shall be permitted as the auxiliary source of current supply as follows:
  1. The required emergency lighting and exit lighting systems in any building or space where a System III is required
  2. The required emergency lighting and exit lighting systems in any building where a System II is required, other than a high rise building which shall comply with 700.30, provided that:
    1. There is sufficient general and, or emergency illumination that is on at all times the building is occupied
    2. The installation, control and maintenance of the emergency system complies with Part V of this article
  3. The required emergency lighting and exit lighting systems in existing high rise residential buildings not over 91 m (300 ft) in height, provided that:
    1. There is sufficient general and, or emergency illumination that is on at all times the building is occupied
    2. The installation, control and maintenance of the emergency system complies with Part V of this article
  4. The final reserve source for places of assembly in existing buildings where a System I is required.
Informational Note: In all new and existing high rise buildings containing residential type units 91 m (300 ft) in height and greater, a diesel generator is the only acceptable method of supply to the required emergency illumination and exit sign system unless allowed by 700.30(C)(Exception No. 2).

Unit battery equipment shall comply with 700.66(C).

Informational Note: Nothing in this Code prohibits battery backed up exit signs as long as they are installed in conformance with the above requirements and conform to relevant sections of the Building Code.

700.44 Battery Systems as Back-Up Source for Exit Signs

AMENDMENT
This section has been amended at the state or city level.
Where no generator or battery inverter system is used, the back-up source of current supply for exit signs shall be approved unit battery exit signs conforming to Section 700.66 and Sections 13-160 -740 through 13-160 -800 of the Chicago Building Code.

Part IV Final Reserve Source of Current Supply

AMENDMENT
This section has been amended at the state or city level.

700.50 Approved Final Reserve Source of Current Supply

AMENDMENT
This section has been amended at the state or city level.
In all cases the final reserve source of current supply shall be one of the following and shall be able to operate at full load for a minimum of 4 hours:
  1. An approved on-site generator in conformance with Article 701
  2. An approved battery system
  3. An approved inverter system

Part V Installation and Control of Systems

AMENDMENT
This section has been amended at the state or city level.

700.59 Installation and Control of Systems

AMENDMENT
This section has been amended at the state or city level.
The following shall be required for installation and control of systems:
  1. Buildings that are closed and not occupied for a portion of the day shall be permitted to have the emergency lighting and exit lighting systems controlled by a manually operable non-locking type switch(es) located only in the main lobby or lobbies, entrances, or entrance stairways.
  2. Where there is more than one main lobby, entrance or entrance stairway switches which turn all exit and emergency lights "ON" shall be permitted to be installed in each location. A switch to turn these lights "OFF" shall be permitted to be installed in only one of these locations.
  3. In high rise buildings with a fire command panel, the switch referred to in this section shall be located in or adjacent to the fire command panel.
  4. In buildings without a fire command panel, the switch(es) shall be identified and the "OFF" switch(es) shall be installed behind locked break glass covers.

700.60 Switches Allowed

AMENDMENT
This section has been amended at the state or city level.
Only the following switches shall be permitted in the emergency lighting and exit lighting systems:
  1. The service switch
  2. Feeder switch(es) (if required)
  3. The required transfer switch(es)
  4. The lobby control switch(es)

700.61 Dimmer and Relay Systems

AMENDMENT
This section has been amended at the state or city level.
A dimmer or relay system containing more than one dimmer or relay and listed for use in emergency systems shall be permitted to be used as a control device for energizing emergency lighting circuits. Upon failure of normal power, the dimmer or relay system shall be permitted to selectively energize only those branch circuits required to provide minimum emergency illumination. All branch circuits supplied by the dimmer or relay system cabinet shall comply with the wiring methods of Article 700.

700.62 Circuit Breakers and Fuses

AMENDMENT
This section has been amended at the state or city level.

(A) Circuit Breakers

AMENDMENT
This section has been amended at the state or city level.
Circuit breakers are switching devices and shall be permitted to be used for service, feeder, or branch circuit overcurrent protection only under the following conditions:
  1. Standard single pole circuit breakers, prominently identified as required by 700.63, used for branch circuit protection where a branch circuit panel is installed in an electrical closet or switchboard room accessible only to qualified persons
  2. Single pole, key-operated circuit breakers used for emergency branch circuit protection in any panel location
  3. Standard circuit breakers may be used where the emergency branch circuit distribution panel feeds only three-phase loads which are required to be on the emergency system
  4. Standard circuit breakers with approved lock-on devices shall be permitted for branch circuits where supplying emergency illumination and exit signs and unit battery equipment complying with 700.66

(B) Fuses

AMENDMENT
This section has been amended at the state or city level.
Standard fused switch equipment shall be permitted to be used for feeder overcurrent protection when installed in locked room accessible only to qualified persons and identified in accordance with 700.63.

700.63 Separate Wiring Systems

AMENDMENT
This section has been amended at the state or city level.

(A) Identification

AMENDMENT
This section has been amended at the state or city level.
All boxes and enclosures (including transfer switches, generators, transformers and power panels) for emergency circuits shall be permanently marked so they will be readily identified as a component of an emergency circuit or system. The legends for all branch circuit and feeder distribution panels shall be marked to identify the loads they serve.

(B) Wiring Separation

AMENDMENT
This section has been amended at the state or city level.
Emergency lighting and exit lighting system feeders and branch circuits, shall be completely separate and independent wiring systems from all other electrical systems starting from the source of current supply to the last lighting outlet on the systems.

Emergency illumination and exit sign equipment branch circuit conductors shall be permitted to occupy the same raceway and share the same branch circuit. These branch circuits shall not be part of multiwire branch circuits.

Emergency unit battery equipment as allowed in 700.43 shall be permitted to share general lighting branch circuits when in conformance with 700.66. Emergency battery unit wiring shall conform to Section 700.66(C).

(C) Wiring Design and Location

AMENDMENT
This section has been amended at the state or city level.
Emergency wiring circuits shall be designed and located to minimize the hazards that might cause failure due to flooding, fire, icing, vandalism, and other adverse conditions.

No apparatus or lighting outlets other than those specified shall be permitted to be connected to exit and emergency lighting systems. Branch circuits shall be allowed a maximum of 15 emergency lighting outlets per branch circuit.

(D) Fire Protection

AMENDMENT
This section has been amended at the state or city level.
In new buildings and buildings undergoing 60% or greater remodeling of interior spaces or the electrical system, the emergency lighting and exit lighting systems shall meet the following additional requirements in (D)(1) through (D)(3) in the following occupancies:
  1. Assembly occupancies for not less than 1,000 persons
  2. High rise buildings
  3. Health care occupancies where persons are not capable of self-preservation
  4. Educational occupancies with more than 300 occupants

(1) Feeder-Circuit Wiring

AMENDMENT
This section has been amended at the state or city level.
Feeder-circuit wiring shall meet one of the following conditions:
  1. Be installed in spaces or areas that are fully protected by an approved automatic fire suppression system
  2. Be a listed electrical circuit protective system with a minimum 2-hour fire rating

    Informational Note No. 1: Electrical circuit protective systems could include but not be limited to thermal barriers or a protective shaft and are tested to UL 1724 Fire Tests for Electrical Circuit Protection Systems.

    Informational Note No. 2: The listing organization provides information for electrical circuit protective systems on proper installation requirements to maintain the fire rating.
  3. Be a listed fire-resistive cable system installed in a metal raceway and supported according to listing requirements

    Informational Note No. 1: Fire-resistive cables are tested to ANSI/UL 2196, Tests for Fire-Resistive Cables.

    Informational Note No. 2: The listing organization provides information for electrical circuit protective systems on proper installation requirements to maintain the fire rating.
  4. Be protected by a listed fire-rated assembly that has a minimum fire rating of 2 hours and contains only emergency wiring circuits
  5. Be encased in a minimum of 50 mm (2 in.) of concrete
  6. Be a cable installed in a metallic raceway listed to maintain circuit integrity for a minimum of 2 hours when installed in accordance with the listing requirements.

(2) Feeder-Circuit Equipment

AMENDMENT
This section has been amended at the state or city level.
Equipment for feeder circuits (including transfer switches, transformers, and panel-boards) shall be located either in spaces fully protected by approved automatic fire suppression systems (including sprinklers, carbon dioxide systems) or in spaces with a 2-hour fire resistance rating.

(3) Generator Control Wiring

AMENDMENT
This section has been amended at the state or city level.
Control conductors installed between the transfer equipment and the emergency generator shall be kept entirely independent of all other wiring and shall meet the conditions of 700.63(D)(1).

700.64 Other Loads

AMENDMENT
This section has been amended at the state or city level.
The following loads shall be permitted to be connected to separate emergency branch circuits.
  1. The loads required to be connected to the high rise emergency system

    Informational Note: See relevant sections of the Chicago Building Code related to high rise emergency requirements.
  2. Emergency voice communication systems that are specifically designed to be used for issuing instructions during emergency conditions
  3. The loads required for hospital emergency systems.

    Informational Note: See Article 517.
  4. Required fire alarm systems.

    Informational Note: See Article 760.
  5. Loads required or allowed elsewhere in this Code to be on the emergency system.

700.65 Existing Multifamily Dwelling Unit Buildings

AMENDMENT
This section has been amended at the state or city level.
For existing multifamily dwelling unit buildings:
  1. Service conductors having an ampacity of 40 amperes shall be permitted for single-phase, three-wire services that serve no more than four 15-ampere branch circuits.
  2. Where the building is 4 stories or less in height and is served directly by vertical front and rear stairwells, all existing stairwell lighting outlets shall be permitted to be supplied from the emergency service. Corridor emergency lighting outlets shall be in addition to the general illumination.
  3. Other loads such as laundry outlets, heating plants, sump pumps, garage and basement lighting shall not be permitted to be supplied from the emergency service.
  4. Emergency lights shall be permitted to be controlled by photocell switches. Time clocks shall not be permitted.
  5. High rise multifamily dwelling unit buildings shall be in conformance with 700.30.

700.66 Approved Unit Battery Equipment and Battery Systems

AMENDMENT
This section has been amended at the state or city level.
The following shall apply to batteries and battery systems for emergency systems:

(A) Dry Cell Batteries

AMENDMENT
This section has been amended at the state or city level.
Dry cell batteries shall not be permitted on any emergency lighting system.

(B) Battery and Battery Inverter Systems

AMENDMENT
This section has been amended at the state or city level.
Battery and battery inverter systems, regardless of voltage, shall be listed for emergency lighting use.

(C) Unit Battery Equipment

AMENDMENT
This section has been amended at the state or city level.

(1) Listing and Labeled

AMENDMENT
This section has been amended at the state or city level.
All unit batteries shall be listed and labeled as emergency luminaire equipment. Individual unit equipment for required standby emergency illumination shall consist of the following:
  1. A rechargeable battery
  2. A battery charging means
  3. Provisions for one or more lamps
  4. A relaying device arranged to automatically energize the lamps upon failure of the supply to the unit equipment
  5. Batteries of suitable rating and capacity to supply and maintain not less than 87-1/2 percent of the nominal battery voltage for the total lamp load associated with the unit for a period of at least 90 minutes
  6. Acid or alkali storage batteries designed and constructed to meet the requirements of emergency service.

(2) Provisions

AMENDMENT
This section has been amended at the state or city level.
The unit equipment shall be provided with:
  1. A test switch for checking the operating conditions of the unit.
  2. A pilot light to indicate when the battery charger is functioning, when tied to the normal source. Functioning of the battery charger is intended to mean the presence of charging voltage.
  3. The pilot light shall not be marked "READY" to indicate power available.

(3) Enclosure

AMENDMENT
This section has been amended at the state or city level.
The unit battery and lamp housing shall be made of metal. In wet or corrosive locations housings that are listed for emergency use and suitable for the environment shall be permitted to be made of other materials.
Exception: Decorative plastic enclosures over metal housings shall be permitted.

(4) Wiring

AMENDMENT
This section has been amended at the state or city level.
The wiring shall comply with the following:
  1. Unit equipment shall be permanently fixed in place and supplied with an approved metallic raceway.
  2. Flexible cord and plug connections shall not be permitted.
  3. The branch circuit feeding the unit equipment shall be the same branch circuit as that serving the normal illumination, or (emergency illumination where present) in the area and connected ahead of any local switches.
  4. The branch-circuit device shall be a type S plug fuse, a circuit breaker of the key operated type, or shall be provided with a locking device to prevent inadvertent opening of the circuit and shall comply with 700.63.
  5. The panel directory shall be prominently marked to identify the circuits that supply the unit batteries.
  6. Where there is a separate and uninterrupted area supplied by a minimum of 3 normal lighting circuits, a separate branch circuit for unit batteries shall be permitted, provided the circuit originates from the same panelboard as that of the normal lighting circuits and is either a type S plug fuse, a circuit breaker of the key operated type, or a circuit breaker provided with a lock on feature.
  7. No more than three lamps shall be permitted to be supplied from one-unit battery.
  8. When a remote lamp is connected to a unit battery, the wiring shall be in an approved metallic raceway and shall be independent of all other wiring and equipment. The wiring shall be limited to 4.57 m (15 ft) and shall not enter the same raceway, box, or cabinet with other wiring.
    Exception: Wiring in a length greater than 4.57 m (15 ft) shall be permitted where it can be shown that by increased wire size, the voltage drop from the battery to the lamp will still allow the lamp to operate at normal brilliance.

(5) Location

AMENDMENT
This section has been amended at the state or city level.
Luminaires shall be so located as to provide the illumination required in 700.6 upon failure of the normal lighting service; these lights shall not be required to be "ON" until failure occurs. In general, one luminaire shall be provided for each 214 m2 (2,300 ft2) of open floor area. Where this number of luminaires does not provide illumination of all areas leading to points of egress, additional luminaires shall be installed.

(6) Lamp Output

AMENDMENT
This section has been amended at the state or city level.
Each lamp shall provide a minimum of 300 lumen output. Single lamps connected to unit batteries that provide the required illumination and are maintained in accordance with subsection (7) below shall be permitted in areas less than 214 m2 (2,300 ft2).

(7) Maintenance

AMENDMENT
This section has been amended at the state or city level.
Unit batteries shall be maintained by qualified maintenance personnel and the following records shall be maintained:
  1. The manufacturer shall supply with each unit battery a complete set of instructions for the operation and maintenance of the equipment.
  2. The date of original installation and of subsequent battery replacements shall be posted conspicuously on the battery container.
  3. Each unit shall be tested annually.
  4. There shall be a water level indicator where applicable and the water shall be checked monthly.
  5. A readily available log of these inspections shall be maintained on a card attached to the unit battery. The card shall contain the name and address of the responsible maintenance personnel that performed the testing required in (c) and (d) of this subsection.

700.67 Generators

AMENDMENT
This section has been amended at the state or city level.
On-site generators are recognized as an approved source of current supply for Emergency Systems I, II, and III. On-site generator(s) used as a current supply for emergency systems shall comply with the requirements of Article 701.

700.68 Tests and Maintenance

AMENDMENT
This section has been amended at the state or city level.

(A) Conduct or Witness Test

AMENDMENT
This section has been amended at the state or city level.
The authority having jurisdiction shall conduct or witness a test of the complete system upon installation and periodically afterward.

(B) Tested Periodically

AMENDMENT
This section has been amended at the state or city level.
Systems shall be tested annually or more frequently on a schedule acceptable to the authority having jurisdiction to ensure the systems are maintained in proper operating condition.

(C) Maintenance

AMENDMENT
This section has been amended at the state or city level.
Emergency system equipment shall be maintained in accordance with manufacturer instructions and industry standards. These instructions shall be kept on-site and made available to the authority having jurisdiction upon request.

(D) Written Record

AMENDMENT
This section has been amended at the state or city level.
A written record shall be kept on such tests and maintenance, maintained on the premises for not less than 10 years, and made available to the authority having jurisdiction upon request.

(E) Testing Under Load

AMENDMENT
This section has been amended at the state or city level.
Means for testing all emergency lighting and power systems during maximum anticipated load conditions shall be provided.

Informational Note 1: For information on testing and maintenance of emergency power supply systems (EPSSs), see NFPA 110-2013, Standard for Emergency and Standby Power Systems.

Informational Note 2: See 700.66(C)(7).

700.69 Special Provisions for Special Circumstances

AMENDMENT
This section has been amended at the state or city level.
The provision of 700.1 thru 700.67 are not intended to limit or inhibit the engineering ingenuity of engineers or contractors in laying out such installations.

Where it can be demonstrated that an alternate design of emergency systems will provide an equivalent or greater level of safety and reliability than that intended by Article 700, the authority having jurisdiction is empowered to grant special permission for alternate emergency systems in lieu of the specifically required systems. The final determination of equivalency, in all cases, shall be made by the authority having jurisdiction.

Part II Circuit Wiring

700.10 Wiring, Emergency System

AMENDMENT
This section has been amended at the state or city level.

(A) Identification

AMENDMENT
This section has been amended at the state or city level.

(B) Wiring

AMENDMENT
This section has been amended at the state or city level.

(C) Wiring Design and Location

AMENDMENT
This section has been amended at the state or city level.

(D) Fire Protection

AMENDMENT
This section has been amended at the state or city level.

(1) Feeder-Circuit Wiring

AMENDMENT
This section has been amended at the state or city level.

(2) Feeder-Circuit Equipment

AMENDMENT
This section has been amended at the state or city level.

(3) Generator Control Wiring

AMENDMENT
This section has been amended at the state or city level.

Part III Sources of Power

700.12 General Requirements

AMENDMENT
This section has been amended at the state or city level.

(A) Storage Battery

AMENDMENT
This section has been amended at the state or city level.

(B) Generator Set

AMENDMENT
This section has been amended at the state or city level.

(1) Prime Mover-Driven

AMENDMENT
This section has been amended at the state or city level.

(2) Internal Combustion Engines as Prime Movers

AMENDMENT
This section has been amended at the state or city level.

(3) Dual Supplies

AMENDMENT
This section has been amended at the state or city level.

(4) Battery Power and Dampers

AMENDMENT
This section has been amended at the state or city level.

(5) Auxiliary Power Supply

AMENDMENT
This section has been amended at the state or city level.

(6) Outdoor Generator Sets

AMENDMENT
This section has been amended at the state or city level.

(C) Uninterruptible Power Supplies

AMENDMENT
This section has been amended at the state or city level.

(D) Separate Service

AMENDMENT
This section has been amended at the state or city level.

(E) Fuel Cell System

AMENDMENT
This section has been amended at the state or city level.

(F) Unit Equipment

AMENDMENT
This section has been amended at the state or city level.

(1) Components of Unit Equipment

AMENDMENT
This section has been amended at the state or city level.

(2) Installation of Unit Equipment

AMENDMENT
This section has been amended at the state or city level.

Part IV Emergency System Circuits for Lighting and Power

700.15 Loads on Emergency Branch Circuits

AMENDMENT
This section has been amended at the state or city level.

700.16 Emergency Illumination

AMENDMENT
This section has been amended at the state or city level.

700.17 Branch Circuits for Emergency Lighting

AMENDMENT
This section has been amended at the state or city level.

700.18 Circuits for Emergency Power

AMENDMENT
This section has been amended at the state or city level.

700.19 Multiwire Branch Circuits

AMENDMENT
This section has been amended at the state or city level.

Part V Control — Emergency Lighting Circuits

700.20 Switch Requirements

AMENDMENT
This section has been amended at the state or city level.

700.21 Switch Location

AMENDMENT
This section has been amended at the state or city level.

700.22 Exterior Lights

AMENDMENT
This section has been amended at the state or city level.

700.23 Dimmer and Relay Systems

AMENDMENT
This section has been amended at the state or city level.

700.24 Directly Controlled Luminaires

AMENDMENT
This section has been amended at the state or city level.

700.25 Branch Circuit Emergency Lighting Transfer Switch

AMENDMENT
This section has been amended at the state or city level.

700.26 Automatic Load Control Relay

AMENDMENT
This section has been amended at the state or city level.

Part VI Overcurrent Protection

700.30 Accessibility

AMENDMENT
This section has been amended at the state or city level.

700.31 Ground-Fault Protection of Equipment

AMENDMENT
This section has been amended at the state or city level.

700.32 Selective Coordination

AMENDMENT
This section has been amended at the state or city level.

Part I General

The provisions of this article apply to the electrical safety of the installation, operation, and maintenance of legally required standby systems consisting of circuits and equipment intended to supply, distribute, and control electricity to required facilities for illumination or power, or both, when the normal electrical supply or system is interrupted.

The systems covered by this article consist only of those that are permanently installed in their entirety, including the power source.

Informational Note No. 1: For further information, see NFPA 99-2015, Health Care Facilities Code.

Informational Note No. 2: For further information regarding performance of emergency and standby power systems, see NFPA 110-2013, Standard for Emergency and Standby Power Systems.

Informational Note No. 3: For further information, see ANSI/IEEE 446-1995, Recommended Practice for Emergency and Standby Power Systems for Industrial and Commercial Applications.

Legally Required Standby Systems. Those systems required and so classed as legally required standby by municipal, state, federal, or other codes or by any governmental agency having jurisdiction. These systems are intended to automatically supply power to selected loads (other than those classed as emergency systems) in the event of failure of the normal source.

Informational Note: Legally required standby systems are typically installed to serve loads, such as heating and refrigeration systems, communications systems, ventilation and smoke removal systems, sewage disposal, lighting systems, and industrial processes, that, when stopped during any interruption of the normal electrical supply, could create hazards or hamper rescue or fire-fighting operations.

(A) Conduct or Witness Test

AMENDMENT
This section has been amended at the state or city level.

(A) Initial Test

AMENDMENT
This section has been amended at the state or city level.
A full load test based on the rating of the generator shall be performed when a generator(s) is first installed. This test shall be witnessed by the authority having jurisdiction, and the required inspection fee shall be paid prior to the test being performed.

(B) Tested Periodically

AMENDMENT
This section has been amended at the state or city level.

(B) Annual Test

AMENDMENT
This section has been amended at the state or city level.
The generator shall be tested annually for a period of at least one hour under heavy load. This test shall be witnessed by the authority having jurisdiction, and the required inspection fee shall be paid prior to the test being performed.

(C) Monthly Tests

AMENDMENT
This section has been amended at the state or city level.
Each generator installation shall be tested monthly under load conditions. A log shall be maintained of these tests. The log shall record the following:
  1. Date and time of day
  2. Voltage and ampere reading (load)
  3. Running time reading at the start of test
  4. Running time reading at the end of the test
  5. Any abnormalities discovered, and other significant data
For testing purposes, a transfer switch(es) shall be provided with a "time-delay on return to normal" which will keep the engine generator running for a minimum of 20 minutes under load once a transfer to the generator has occurred.

(C)(D) Maintenance

AMENDMENT
This section has been amended at the state or city level.
Legally required standby system equipment shall be maintained in accordance with manufacturer instructions and industry standards. These instructions shall be kept on-site and made available to the authority having jurisdiction upon request.

(D)(E) Written Record

AMENDMENT
This section has been amended at the state or city level.
A written record shall be kept on such tests and maintenance, maintained on the premises for not less than 10 years, and made available to the authority having jurisdiction upon request.

(E)(F) Testing Under Load

AMENDMENT
This section has been amended at the state or city level.
Means for testing legally required standby systems under load shall be provided.

Informational Note: For information on testing and maintenance of emergency power supply systems (EPSSs), see NFPA 110-2013, Standard for Emergency and Standby Power Systems.

A legally required standby system shall have adequate capacity and rating for the supply of all equipment intended to be operated at one time. Legally required standby system equipment shall be suitable for the maximum available fault current at its terminals.

The legally required standby alternate power source shall be permitted to supply both legally required standby and optional standby system loads under either of the following conditions:

  1. Where the alternate source has adequate capacity to handle all connected loads
  2. Where automatic selective load pickup and load shedding is provided that will ensure adequate power to the legally required standby circuits
Transfer equipment, including automatic transfer switches, shall be automatic and identified for standby use and approved by the authority having jurisdiction. Transfer equipment shall be designed and installed to prevent the inadvertent interconnection of normal and alternate sources of supply in any operation of the transfer equipment. Transfer equipment and electric power production systems installed to permit operation in parallel with the normal source shall meet the requirements of Article 705.
Means to bypass and isolate the transfer switch equipment shall be permitted. Where bypass isolation switches are used, inadvertent parallel operation shall be avoided.
Automatic transfer switches shall be electrically operated and mechanically held. Automatic transfer switches shall be listed for emergency use.
The short-circuit current rating of the transfer equipment, based on the specific overcurrent protective device type and settings protecting the transfer equipment, shall be field marked on the exterior of the transfer equipment.

(E) Location

AMENDMENT
This section has been amended at the state or city level.
Transfer equipment shall not be located in the same room as the generator or service entrance equipment.
Audible and visual signal devices shall be provided, where practicable, for the purposes described in 701.6(A), (B), (C), and (D).
To indicate malfunction of the standby source.
To indicate that the standby source is carrying load.
To indicate that the battery charger is not functioning.

Informational Note: For signals for generator sets, see NFPA 110-2013, Standard for Emergency and Standby Power Systems.

To indicate a ground fault in solidly grounded wye, legally required standby systems of more than 150 volts to ground and circuit-protective devices rated 1000 amperes or more. The sensor for the ground-fault signal devices shall be located at, or ahead of, the main system disconnecting means for the legally required standby source, and the maximum setting of the signal devices shall be for a ground-fault current of 1200 amperes. Instructions on the course of action to be taken in event of indicated ground fault shall be located at or near the sensor location.

For systems with multiple emergency sources connected to a paralleling bus, the ground fault sensor shall be permitted at an alternate location.

Informational Note: For signals for generator sets, see NFPA 110-2013, Standard for Emergency and Standby Power Systems.

A sign shall be placed at the service entrance indicating type and location of each on-site legally required standby power source.

Exception: A sign shall not be required for individual unit equipment as specified in 701.12(G).

Where removal of a grounding or bonding connection in normal power source equipment interrupts the grounding electrode conductor connection to the alternate power source(s) grounded conductor, a warning sign shall be installed at the normal power source equipment stating:

WARNING
SHOCK HAZARD EXISTS IF GROUNDING ELECTRODE CONDUCTOR OR BONDING JUMPER CONNECTION IN THIS EQUIPMENT IS REMOVED WHILE ALTERNATE SOURCE(S) IS ENERGIZED.

The warning sign(s) or label(s) shall comply with 110.21(B).

701.8 Signal Annunciator

AMENDMENT
This section has been amended at the state or city level.
A storage-battery powered remote annunciator shall be installed outside of the generator room in a location readily observed by operating personnel at a regular work station. In addition, unless a regular work station is continuously manned, an appropriately labeled audible and visual signal shall be installed at a manned location. The remote annunciator panel shall include a voltage meter and a lamp test function and shall be permitted to have an alarm silencing switch and pilot light to indicate alarm silenced. In addition to the signals described in 701.6 (A), (B), (C) and (D) there also shall be a signal to indicate when the generator is not in the automatic position.

701.9 Plans Required

AMENDMENT
This section has been amended at the state or city level.
Complete and detailed plans and specifications of all emergency generators shall be submitted to the authority having jurisdiction for review before any construction work is started. These documents shall include the following:
  1. A single line drawing of the complete emergency and/or essential electrical system. The drawing shall include all components of the system(s) including utility source(s), generator(s), transfer switch(es), feeder distribution panel(s), and branch circuit panelboard(s).
  2. A floor or site plan of the engine generator room or location which shows to scale the location of all equipment and the working space provided.
  3. Specifications for the method to refuel the generator motor.

Part II Circuit Wiring

701.10 Wiring Legally Required Standby Systems

AMENDMENT
This section has been amended at the state or city level.
The legally required standby system wiring shall comply with 700.63.

Part III Sources of Power

Current supply shall be such that, in the event of failure of the normal supply to, or within, the building or group of buildings concerned, legally required standby power will be available within the time required for the application but not to exceed 60 seconds. The supply system for legally required standby purposes, in addition to the normal services to the building, shall be permitted to comprise one or more of the types of systems described in 701.12(A) through (F). Unit equipment in accordance with 701.12(G) shall satisfy the applicable requirements of this article.

In selecting a legally required standby source of power, consideration shall be given to the type of service to be rendered, whether of short-time duration or long duration.

Consideration shall be given to the location or design, or both, of all equipment to minimize the hazards that might cause complete failure due to floods, fires, icing, and vandalism.

Informational Note: For further information, see ANSI/IEEE 493-2007, Recommended Practice for the Design of Reliable Industrial and Commercial Power Systems.

Storage batteries shall be of suitable rating and capacity to supply and maintain the total load for a minimum period of 11/2 hours without the voltage applied to the load falling below 871/2 percent of normal. Automotive-type batteries shall not be used.

An automatic battery charging means shall be provided.

For a generator set driven by a prime mover acceptable to the authority having jurisdiction and sized in accordance with 701.4, means shall be provided for automatically starting the prime mover upon failure of the normal service and for automatic transfer and operation of all required electrical circuits. A time-delay feature permitting a 15-minute setting shall be provided to avoid retransfer in case of short-time re-establishment of the normal source.

(2) Internal Combustion Engines as Prime Mover

AMENDMENT
This section has been amended at the state or city level.
Where internal combustion engines are used as the prime mover, an on-site fuel supply shall be provided with an on-premises fuel supply sufficient for not less than 4 hours of full-demand operation of the system. Where power is needed for the operation of the fuel transfer pumps to deliver fuel to a generator set day tank, the pumps shall be connected to the legally required standby power system.
Prime movers shall not be solely dependent on a public utility gas system for their fuel supply or on a municipal water supply for their cooling systems. Means shall be provided for automatically transferring one fuel supply to another where dual fuel supplies are used.

Exception: Where acceptable to the authority having jurisdiction, the use of other than on-site fuels shall be permitted where there is a low probability of a simultaneous failure of both the off-site fuel delivery system and power from the outside electrical utility company.

Where a storage battery is used for control or signal power or as the means of starting the prime mover, it shall be suitable for the purpose and shall be equipped with an automatic charging means independent of the generator set.
Where an outdoor housed generator set is equipped with a readily accessible disconnecting means in accordance with 445.18, and the disconnecting means is located within sight of the building or structure supplied, an additional disconnecting means shall not be required where ungrounded conductors serve or pass through the building or structure. Where the generator supply conductors terminate at a disconnecting means in or on a building or structure, the disconnecting means shall meet the requirements of 225.36.
Uninterruptible power supplies used to provide power for legally required standby systems shall comply with the applicable provisions of 701.12(A) and (B).
Where approved, a separate service shall be permitted as a legally required source of standby power. This service shall be in accordance with the applicable provisions of Article 230, with a separate service drop or lateral or a separate set of overhead or underground service conductors sufficiently remote electrically and physically from any other service to minimize the possibility of simultaneous interruption of supply from an occurrence in another service.
Where acceptable to the authority having jurisdiction, connections located ahead of and not within the same cabinet, enclosure, vertical switchgear section, or vertical switchboard section as the service disconnecting means shall be permitted. The legally required standby service shall be sufficiently separated from the normal main service disconnecting means to minimize simultaneous interruption of supply through an occurrence within the building or groups of buildings served.

Informational Note: See 230.82 for equipment permitted on the supply side of a service disconnecting means.

Fuel cell systems used as a source of power for legally required standby systems shall be of suitable rating and capacity to supply and maintain the total load for not less than 2 hours of full-demand operation.

Installation of a fuel cell system shall meet the requirements of Parts II through VIII of Article 692.

Where a single fuel cell system serves as the normal supply for the building or group of buildings concerned, it shall not serve as the sole source of power for the legally required standby system.

Individual unit equipment for legally required standby illumination shall consist of the following:
  1. A rechargeable battery
  2. A battery charging means
  3. Provisions for one or more lamps mounted on the equipment and shall be permitted to have terminals for remote lamps
  4. A relaying device arranged to energize the lamps automatically upon failure of the supply to the unit equipment

The batteries shall be of suitable rating and capacity to supply and maintain the total lamp load associated with the unit for not less than (a) or (b):

(a) For a period of 11/2 hours, without the voltage falling below 871/2 percent of normal voltage

(b) The unit equipment shall supply and maintain not less than 60 percent of the initial emergency illumination for a period of at least 11/2 hours.

Unit equipment shall be permanently fixed in place (i.e., not portable) and shall have all wiring to each unit installed in accordance with the requirements of any of the wiring methods in Chapter 3. Flexible cord-and-plug connection shall be permitted, provided that the cord does not exceed 900 mm (3 ft) in length. The branch circuit feeding the unit equipment shall be the same branch circuit as that serving the normal lighting in the area and connected ahead of any local switches. Legally required standby luminaires that obtain power from a unit equipment and are not part of the unit equipment shall be wired to the unit equipment by one of the wiring methods of Chapter 3.

Exception: In a separate and uninterrupted area supplied by a minimum of three normal lighting circuits, a separate branch circuit for unit equipment shall be permitted if it originates from the same panelboard as that of the normal lighting circuits and is provided with a lock-on feature.

Part IV Overcurrent Protection

The branch-circuit overcurrent devices in legally required standby circuits shall be accessible to authorized persons only.
The alternate source for legally required standby systems shall not be required to provide ground-fault protection of equipment with automatic disconnecting means. Ground-fault indication at the legally required standby source shall be provided in accordance with 701.6(D) if ground-fault protection of equipment with automatic disconnecting means is not provided.
Legally required standby system(s) overcurrent devices shall be selectively coordinated with all supply-side overcurrent protective devices.

Selective coordination shall be selected by a licensed professional engineer or other qualified persons engaged primarily in the design, installation, or maintenance of electrical systems. The selection shall be documented and made available to those authorized to design, install, inspect, maintain, and operate the system.

Exception: Selective coordination shall not be required between two overcurrent devices located in series if no loads are connected in parallel with the downstream device.

Part V Other Requirements

AMENDMENT
This section has been amended at the state or city level.

701.29 Generator Auxiliary Equipment

AMENDMENT
This section has been amended at the state or city level.
Auxiliary electrical equipment essential to the running of the generator shall be connected to one or more of the generator disconnect switches. This disconnect switch(es) shall feed no other loads. Essential generator auxiliary equipment includes, but is not limited to:
  1. Cooling fan motor for a remote radiator
  2. Auxiliary water pump
  3. Storage tank fuel pump
  4. Normally off, unswitched emergency lights at the generator, control panel, main distribution and service switchboard locations
  5. Cool-down timer

701.30 Cool-Down Timer(s)

AMENDMENT
This section has been amended at the state or city level.
A cool-down timer(s) shall be installed so that in every case when generator operation is initiated and after the normal source of current supply is restored, the generator shall run without load for time equal to, or greater than, the generator manufacturers recommendations.

701.31 Isolated Wiring

AMENDMENT
This section has been amended at the state or city level.
The conduit and wiring of emergency systems shall be completely separate from all other wiring from the source to the load in accordance with Article 700. The wiring of emergency systems shall not occupy common raceways, wireways, junction boxes, or header boxes with other conductors.

701.32 Identification

AMENDMENT
This section has been amended at the state or city level.
All elements of the emergency system such as, transfer switches, distribution centers, transformers and service switches shall be plainly and visibly identified by appropriate nameplates as being part of the emergency system. The legends for all branch circuit and feeder distribution panels shall be filled out identifying the circuits and the loads they serve.

A copy of the one-line wiring diagram of the entire emergency system describing its basic mode of operation as described in 700.3(c) shall be displayed at the service switch location, the generator location, and the transfer switch locations for the reference of operating and maintenance personnel.

Part I General

The provisions of this article apply to the installation and operation of optional standby systems.

The systems covered by this article consist of those that are permanently installed in their entirety, including prime movers, and those that are arranged for a connection to a premises wiring system from a portable alternate power supply.

Optional Standby Systems. Those systems intended to supply power to public or private facilities or property where life safety does not depend on the performance of the system. These systems are intended to supply on-site generated power to selected loads either automatically or manually.

Informational Note: Optional standby systems are typically installed to provide an alternate source of electric power for such facilities as industrial and commercial buildings, farms, and residences and to serve loads such as heating and refrigeration systems, data processing and communications systems, and industrial processes that, when stopped during any power outage, could cause discomfort, serious interruption of the process, damage to the product or process, or the like.

Optional standby system equipment shall be suitable for the maximum available short-circuit current at its terminals.
The calculations of load on the standby source shall be made in accordance with Article 220 or by another approved method.
Where manual transfer equipment is used, an optional standby system shall have adequate capacity and rating for the supply of all equipment intended to be operated at one time. The user of the optional standby system shall be permitted to select the load connected to the system.
Where automatic transfer equipment is used, an optional standby system shall comply with (2)(a) or (2)(b).

(a) Full Load. The standby source shall be capable of supplying the full load that is transferred by the automatic transfer equipment.

(b) Load Management. Where a system is employed that will automatically manage the connected load, the standby source shall have a capacity sufficient to supply the maximum load that will be connected by the load management system.

Transfer equipment shall be suitable for the intended use and designed and installed so as to prevent the inadvertent interconnection of normal and alternate sources of supply in any operation of the transfer equipment. Transfer equipment and electric power production systems installed to permit operation in parallel with the normal source shall meet the requirements of Article 705.

Transfer equipment, located on the load side of branch circuit protection, shall be permitted to contain supplemental overcurrent protection having an interrupting rating sufficient for the available fault current that the generator can deliver. The supplementary overcurrent protection devices shall be part of a listed transfer equipment.

Transfer equipment shall be required for all standby systems subject to the provisions of this article and for which an electric utility supply is either the normal or standby source.

Exception: Temporary connection of a portable generator without transfer equipment shall be permitted where conditions of maintenance and supervision ensure that only qualified persons service the installation and where the normal supply is physically isolated by a lockable disconnecting means or by disconnection of the normal supply conductors.

The short-circuit current rating of the transfer equipment, based on the specific overcurrent protective device type and settings protecting the transfer equipment, shall be field marked on the exterior of the transfer equipment.

Audible and visual signal devices shall be provided, where practicable, for the following purposes specified in 702.6(A) and (B).
To indicate malfunction of the optional standby source.
To indicate that the optional standby source is carrying load.

Exception: Signals shall not be required for portable standby power sources.

A sign shall be placed at the service-entrance equipment that indicates the type and location of each on-site optional standby power source. A sign shall not be required for individual unit equipment for standby illumination.
Where removal of a grounding or bonding connection in normal power source equipment interrupts the grounding electrode conductor connection to the alternate power source(s) grounded conductor, a warning sign shall be installed at the normal power source equipment stating:

WARNING
SHOCK HAZARD EXISTS IF GROUNDING ELECTRODE CONDUCTOR OR BONDING JUMPER CONNECTION IN THIS EQUIPMENT IS REMOVED WHILE ALTERNATE SOURCE(S) IS ENERGIZED.

The warning sign(s) or label(s) shall comply with 110.21(B).

Where a power inlet is used for a temporary connection to a portable generator, a warning sign shall be placed near the inlet to indicate the type of derived system that the system is capable of based on the wiring of the transfer equipment. The sign shall display one of the following warnings:

WARNING:
FOR CONNECTION OF A SEPARATELY DERIVED (BONDED NEUTRAL) SYSTEM ONLY
or
WARNING:
FOR CONNECTION OF A NONSEPARATELY DERIVED (FLOATING NEUTRAL) SYSTEM ONLY

Part II Wiring

The optional standby system wiring shall be permitted to occupy the same raceways, cables, boxes, and cabinets with other general wiring.
Where a portable optional standby source is used as a separately derived system, it shall be grounded to a grounding electrode in accordance with 250.30.
Where a portable optional standby source is used as a nonseparately derived system, the equipment grounding conductor shall be bonded to the system grounding electrode.
Where an outdoor housed generator set is equipped with a readily accessible disconnecting means in accordance with 445.18, and the disconnecting means is located within sight of the building or structure supplied, an additional disconnecting means shall not be required where ungrounded conductors serve or pass through the building or structure. Where the generator supply conductors terminate at a disconnecting means in or on a building or structure, the disconnecting means shall meet the requirements of 225.36.
Where a portable generator, rated 15 kW or less, is installed using a flanged inlet or other cord- and plug-type connection, a disconnecting means shall not be required where ungrounded conductors serve or pass through a building or structure.
Equipment containing power inlets for the connection of a generator source shall be listed for the intended use. Systems with power inlets shall be equipped with an interlocked disconnecting means.

Exception No. 1: If the inlet device is rated as a disconnecting means

Exception No. 2: Supervised industrial installations where permanent space is identified for the portable generator located within line of sight of the power inlets shall not be required to have interlocked disconnecting means nor inlets rated as disconnects.

Part I General

This article covers installation of one or more electric power production sources operating in parallel with a primary source(s) of electricity.

Informational Note: Examples of the types of primary sources include a utility supply or an on-site electric power source(s).

Interactive Inverter Output Circuit. The conductors between the interactive inverter and the service equipment or another electric power production source, such as a utility, for electrical production and distribution network.

Microgrid Interconnect Device (MID). A device that allows a microgrid system to separate from and reconnect to a primary power source.

Microgrid System. A premises wiring system that has generation, energy storage, and load(s), or any combination thereof, that includes the ability to disconnect from and parallel with the primary source.

Informational Note: The application of Article 705 to microgrid systems is limited by the exclusions in 90.2(B)(5) related to electric utilities.

Multimode Inverter. Equipment having the capabilities of both the interactive inverter and the stand-alone inverter.

Power Production Equipment. The generating source, and all distribution equipment associated with it, that generates electricity from a source other than a utility supplied service.

Informational Note: Examples of power production equipment include such items as generators, solar photovoltaic systems, and fuel cell systems.

Interconnected electric power production sources shall comply with this article and also with the applicable requirements of the articles in Table 705.3.

Table 705.3 Other Articles

Equipment/System Article
Generators 445
Solar photovoltaic systems 690
Fuel cell systems 692
Wind electric systems 694
Emergency systems 700
Legally required standby systems 701
Optional standby systems 702
Energy storage systems 706
Stand-alone systems 710
DC microgrids 712
All equipment shall be approved for the intended use. Interactive inverters for interconnection to systems interactive equipment intended to operate in parallel with the electric power system including, but not limited to, interactive inverters, engine generators, energy storage equipment, and wind turbines shall be listed and or field labeled for the intended use of interconnection service.
Installation of one or more electrical power production sources operating in parallel with a primary source(s) of electricity shall be performed only by qualified persons.

Informational Note: See Article 100 for the definition of Qualified Person.

A permanent plaque or directory denoting the location of all electric power source disconnecting means on or in the premises shall be installed at each service equipment location and at the location(s) of the system disconnect(s) for all electric power production sources capable of being interconnected. The marking shall comply with 110.21(B).

Exception: Installations with large numbers of power production sources shall be permitted to be designated by groups.

The output of an interconnected electric power source shall be connected as specified in 705.12(A) or (B).
An electric power production source shall be permitted to be connected to the supply side of the service disconnecting means as permitted in 230.82(6). The sum of the ratings of all overcurrent devices connected to power production sources shall not exceed the rating of the service.
The output of an interconnected electric power source shall be permitted to be connected to the load side of the service disconnecting means of the other source(s) at any distribution equipment on the premises. Where distribution equipment, including switchgear, switchboards, or panelboards, is fed simultaneously by a primary source(s) of electricity and one or more other power source(s), and where this distribution equipment is capable of supplying multiple branch circuits or feeders, or both, the interconnecting provisions for other power sources shall comply with 705.12(B)(1) through (B)(5).
Each source interconnection of one or more power sources installed in one system shall be made at a dedicated circuit breaker or fusible disconnecting means.
One hundred twenty-five percent of the power source output circuit current shall be used in ampacity calculations for the following:
  1. Feeders. Where the power source output connection is made to a feeder at a location other than the opposite end of the feeder from the primary source overcurrent device, that portion of the feeder on the load side of the power source output connection shall be protected by one of the following:
    1. The feeder ampacity shall be not less than the sum of the primary source overcurrent device and 125 percent of the power source output circuit current.
    2. An overcurrent device on the load side of the power source connection shall be rated not greater than the ampacity of the feeder.
  2. Taps. In systems where power source output connections are made at feeders, any taps shall be sized based on the sum of 125 percent of the power source(s) output circuit current and the rating of the overcurrent device protecting the feeder conductors as calculated in 240.21(B).
  3. Busbars. One of the methods that follows shall be used to determine the ratings of busbars in panelboards.

(a) The sum of 125 percent of the power source(s) output circuit current and the rating of the overcurrent device protecting the busbar shall not exceed the ampacity of the busbar.

Informational Note: This general rule assumes no limitation in the number of the loads or sources applied to busbars or their locations.

(b) Where two sources, one a primary power source and the other another power source, are located at opposite ends of a busbar that contains loads, the sum of 125 percent of the power source(s) output circuit current and the rating of the overcurrent device protecting the busbar shall not exceed 120 percent of the ampacity of the busbar. The busbar shall be sized for the loads connected in accordance with Article 220. A permanent warning label shall be applied to the distribution equipment adjacent to the back-fed breaker from the power source that displays the following or equivalent wording:

WARNING:
POWER SOURCE OUTPUT CONNECTION — DO NOT RELOCATE THIS OVERCURRENT DEVICE.

The warning sign(s) or label(s) shall comply with 110.21(B).

(c) The sum of the ampere ratings of all overcurrent devices on panelboards, both load and supply devices, excluding the rating of the overcurrent device protecting the busbar, shall not exceed the ampacity of the busbar. The rating of the overcurrent device protecting the busbar shall not exceed the rating of the busbar. Permanent warning labels shall be applied to distribution equipment displaying the following or equivalent wording:

WARNING:
THIS EQUIPMENT FED BY MULTIPLE SOURCES. TOTAL RATING OF ALL OVERCURRENT DEVICES EXCLUDING MAIN SUPPLY OVERCURRENT DEVICE SHALL NOT EXCEED AMPACITY OF BUSBAR.

The warning sign(s) or label(s) shall comply with 110.21(B).

(d) A connection at either end, but not both ends, of a center-fed panelboard in dwellings shall be permitted where the sum of 125 percent of the power source(s) output circuit current and the rating of the overcurrent device protecting the busbar does not exceed 120 percent of the current rating of the busbar.

(e) Connections shall be permitted on multiple-ampacity busbars where designed under engineering supervision that includes available fault current and busbar load calculations.

Equipment containing overcurrent devices in circuits supplying power to a busbar or conductor supplied from multiple sources shall be marked to indicate the presence of all sources.
Circuit breakers, if backfed, shall be suitable for such operation.

Informational Note: Fused disconnects, unless otherwise marked, are suitable for backfeeding.

Listed plug-in-type circuit breakers backfed from electric power sources that are listed and identified as interactive shall be permitted to omit the additional fastener normally required by 408.36(D) for such applications.
The output of a generator or other electric power production source operating in parallel with an electrical supply system shall be compatible with the voltage, wave shape, and frequency of the system to which it is connected.

Informational Note: The term compatible does not necessarily mean matching the primary source wave shape.

Consideration shall be given to the contribution of fault currents from all interconnected power sources for the interrupting and short-circuit current ratings of equipment on interactive systems.
Means shall be provided to disconnect all ungrounded conductors of an electric power production source(s) from all other conductors.
Means shall be provided to disconnect power production equipment, such as interactive inverters or transformers associated with a power production source, from all ungrounded conductors of all sources of supply. Equipment intended to be operated and maintained as an integral part of a power production source exceeding 1000 volts shall not be required to have a disconnecting means.
The disconnecting means for ungrounded conductors shall consist of a manual or power operated switch(es) or circuit breaker(s) that complies with the following:
  1. Located where readily accessible
  2. Externally operable without exposing the operator to contact with live parts and, if power operated, of a type that is opened by hand in the event of a power-supply failure
  3. Plainly indicate whether in the open (off) or closed (on) position
  4. Have ratings sufficient for the maximum circuit current, available short-circuit current, and voltage that is available at the terminals
  5. Where the line and load terminals are capable of being energized in the open position, marked in accordance with the warning in 690.13(B)

    Informational Note : In parallel generation systems, some equipment, including knife blade switches and fuses, is likely to be energized from both directions. See 240.40.

  6. Simultaneously disconnect all ungrounded conductors of the circuit
  7. Be lockable in the open (off) position in accordance with 110.25
A readily accessible means shall be provided to disconnect the interactive system from all wiring systems including power systems, energy storage systems, and utilization equipment and its associated premises wiring.
Conductors shall be protected in accordance with Article 240. Equipment and conductors connected to more than one electrical source shall have a sufficient number of overcurrent devices located so as to provide protection from all sources.
Solar photovoltaic systems shall be protected in accordance with Article 690.
Overcurrent protection for a transformer with a source(s) on each side shall be provided in accordance with 450.3 by considering first one side of the transformer, then the other side of the transformer, as the primary.
Fuel cell systems shall be protected in accordance with Article 692.
Interactive inverters shall be protected in accordance with 705.65.
Generators shall be protected in accordance with 705.130.
Overcurrent protection for electric power production source conductors, connected to the supply side of the service disconnecting means in accordance with 705.12(A), shall be located within 3 m (10 ft) of the point where the electric power production source conductors are connected to the service.

Informational Note: This overcurrent protection protects against short-circuit current supplied from the primary source(s) of electricity.

Exception: Where the overcurrent protection for the power production source is located more than 3 m (10 ft) from the point of connection for the electric power production source to the service, cable limiters or current-limited circuit breakers for each ungrounded conductor shall be installed at the point where the electric power production conductors are connected to the service.

Where ground-fault protection is used, the output of an interactive system shall be connected to the supply side of the ground-fault protection.

Exception: Connection shall be permitted to be made to the load side of ground-fault protection, if there is ground-fault protection for equipment from all ground-fault current sources.

Upon loss of primary source, an electric power production source shall be automatically disconnected from all ungrounded conductors of the primary source and shall not be reconnected until the primary source is restored.

Exception: A listed interactive inverter shall be permitted to automatically cease exporting power upon loss of primary source and shall not be required to automatically disconnect all ungrounded conductors from the primary source. A listed interactive inverter shall be permitted to automatically or manually resume exporting power to the utility once the primary source is restored.

Informational Note No. 1: Risks to personnel and equipment associated with the primary source could occur if an utility interactive electric power production source can operate as an intentional island. Special detection methods are required to determine that a primary source supply system outage has occurred and whether there should be automatic disconnection. When the primary source supply system is restored, special detection methods can be required to limit exposure of power production sources to out-of-phase reconnection.

Informational Note No. 2: Induction-generating equipment on systems with significant capacitance can become self-excited upon loss of the primary source and experience severe overvoltage as a result.

An interactive inverter shall be permitted to operate as a stand-alone system to supply loads that have been disconnected from electrical production and distribution network sources.

A 3-phase electric power production source shall be automatically disconnected from all ungrounded conductors of the interconnected systems when one of the phases of that source opens. This requirement shall not be applicable to an electric power production source providing power for an emergency or legally required standby system.

Exception: A listed interactive inverter shall be permitted to automatically cease exporting power when one of the phases of the source opens and shall not be required to automatically disconnect all ungrounded conductors from the primary source. A listed interactive inverter shall be permitted to automatically or manually resume exporting power to the utility once all phases of the source are restored.

Interconnected electric power production sources shall be grounded in accordance with Article 250.

Exception: For direct-current systems connected through an inverter directly to a grounded service, other methods that accomplish equivalent system protection and that utilize equipment listed and identified for the use shall be permitted.

Part II Interactive Inverters

The maximum current for the specific circuit shall be calculated in accordance with 705.60(A)(1) and (A)(2).
The maximum current shall be the maximum rated input current of the inverter.
The maximum current shall be the inverter continuous output current rating.
Inverter system currents shall be considered to be continuous. The circuit conductors and overcurrent devices shall be sized to carry not less than 125 percent of the maximum currents as calculated in 705.60(A). The rating or setting of overcurrent devices shall be permitted in accordance with 240.4(B) and (C).

Exception: Circuits containing an assembly together with its overcurrent device(s) that is listed for continuous operation at 100 percent of its rating shall be permitted to be utilized at 100 percent of its rating.

Inverter input circuits, inverter output circuits, and storage battery circuit conductors and equipment shall be protected in accordance with the requirements of Article 240. Circuits connected to more than one electrical source shall have overcurrent devices located so as to provide overcurrent protection from all sources.

Exception: An overcurrent device shall not be required for circuit conductors sized in accordance with 705.60(B) and located where one of the following applies:

  1. There are no external sources such as parallel-connected source circuits, batteries, or backfeed from inverters.
  2. The short-circuit currents from all sources do not exceed the ampacity of the conductors.

Informational Note: Possible backfeed of current from any source of supply, including a supply through an inverter into the inverter output circuit and inverter source circuits, is a consideration in determining whether adequate overcurrent protection from all sources is provided for conductors and modules.

Overcurrent protection for a transformer with a source(s) on each side shall be provided in accordance with 450.3 by considering first one side of the transformer, then the other side of the transformer, as the primary.

Exception: A power transformer with a current rating on the side connected toward the interactive inverter output that is not less than the rated continuous output current of the inverter shall be permitted without overcurrent protection from that source.

Power source output circuit conductors that are connected to a feeder, if smaller than the feeder conductors, shall be sized to carry not less than the larger of the current as calculated in 705.60(B) or as calculated in accordance with 240.21(B) based on the over-current device protecting the feeder.
Interactive inverters shall be permitted to be mounted on roofs or other exterior areas that are not readily accessible. These installations shall comply with (1) through (4):
  1. A dc disconnecting means shall be mounted within sight of or in the inverter.
  2. An ac disconnecting means shall be mounted within sight of or in the inverter.
  3. An additional ac disconnecting means for the inverter shall comply with 705.22.
  4. A plaque shall be installed in accordance with 705.10.
Utility-interactive power systems employing energy storage shall also be marked with the maximum operating voltage, including any equalization voltage, and the polarity of the grounded circuit conductor.
Hybrid systems shall be permitted to be interconnected with interactive inverters.
The ampacity of the neutral conductors shall comply with either (A) or (B).
If a single-phase, 2-wire inverter output is connected to the neutral and one ungrounded conductor (only) of a 3-wire system or of a 3-phase, 4-wire, wye-connected system, the maximum load connected between the neutral and any one ungrounded conductor plus the inverter output rating shall not exceed the ampacity of the neutral conductor.
A conductor used solely for instrumentation, voltage detection, or phase detection and connected to a single-phase or 3-phase interactive inverter, shall be permitted to be sized at less than the ampacity of the other current-carrying conductors and shall be sized equal to or larger than the equipment grounding conductor.
Single-phase inverters for hybrid systems and ac modules in interactive hybrid systems shall be connected to 3-phase power systems in order to limit unbalanced voltages to not more than 3 percent.

Informational Note: For interactive single-phase inverters, unbalanced voltages can be minimized by the same methods that are used for single-phase loads on a 3-phase power system. See ANSI/C84.1-2011, Electric Power Systems and EquipmentVoltage Ratings (60 Hertz).

Three-phase inverters and 3-phase ac modules in interactive systems shall have all phases automatically de-energized upon loss of, or unbalanced, voltage in one or more phases unless the interconnected system is designed so that significant unbalanced voltages will not result.

Part III Generators

Conductors shall be protected in accordance with Article 240. Equipment and conductors connected to more than one electrical source shall have overcurrent devices located so as to provide protection from all sources. Generators shall be protected in accordance with 445.12.
Synchronous generators in a parallel system shall be provided with the necessary equipment to establish and maintain a synchronous condition.

Part IV Microgrid Systems

Microgrid systems shall be permitted to disconnect from the primary source of power or other interconnected electric power production sources and operate as a separate microgrid system.
Connections to primary power sources that are external to the microgrid system shall comply with the requirements of 705.12.
Microgrid systems that reconnect to primary power sources shall be provided with the necessary equipment to establish a synchronous transition.
Microgrid interconnect devices shall comply with the following:
  1. Be required for any connection between a microgrid system and a primary power source
  2. Be listed or field labeled for the application
  3. Have sufficient number of overcurrent devices located to provide overcurrent protection from all sources

Informational Note: MID functionality is often incorporated in an interactive or multimode inverter, energy storage system, or similar device identified for interactive operation.

Part I General

This article applies to all permanently installed energy storage systems (ESS) operating at over 50 volts ac or 60 volts dc that may be stand-alone or interactive with other electric power production sources.

Informational Note: The following standards are frequently referenced for the installation of energy storage systems:

  1. NFPA 111-2013, Standard on Stored Electrical Energy Emergency and Standby Systems
  2. IEEE 484-2008, Recommended Practice for Installation Design and Installation of Vented Lead-Acid Batteries for Stationary Applications
  3. IEEE 485-1997, Recommended Practice for Sizing Vented Lead-Acid Storage Batteries for Stationary Applications
  4. IEEE 1145-2007, Recommended Practice for Installation and Maintenance of Nickel-Cadmium Batteries for Photovoltaic (PV) Systems
  5. IEEE 1187-2002, Recommended Practice for Installation Design, and Installation of Valve-Regulated Lead-Acid Batteries for Stationary Applications
  6. IEEE 1578-2007, Recommended Practice for Stationary Battery Electrolyte Spill Containment and Management
  7. IEEE 1635/ASHRAE 21-2012, Guide for the Ventilation and Thermal Management of Batteries for Stationary Applications
  8. UL 810A, Electrochemical Capacitors
  9. UL 1973, Batteries for Use in Light Electric Rail (LER) Applications and Stationary Applications
  10. UL 1989, Standard for Standby Batteries
  11. UL Subject 2436, Spill Containment For Stationary Lead Acid Battery Systems
  12. UL Subject 9540, Safety of Energy Storage Systems and Equipment

Battery. Two or more cells connected together electrically in series, in parallel, or a combination of both to provide the required operating voltage and current levels.

Cell. The basic electrochemical unit, characterized by an anode and a cathode, used to receive, store, and deliver electrical energy.

Container. A vessel that holds the plates, electrolyte, and other elements of a single unit, comprised of one or more cells, in a battery. It can be referred to as a jar or case.

Diversion Charge Controller. Equipment that regulates the charging process of an ESS by diverting power from energy storage to direct-current or alternating-current loads or to an interconnected utility service.

Electrolyte. The medium that provides the ion transport mechanism between the positive and negative electrodes of a cell.

Energy Storage System (ESS). One or more components assembled together capable of storing energy for use at a future time. ESS(s) can include but is not limited to batteries, capacitors, and kinetic energy devices (e.g., flywheels and compressed air). These systems can have ac or dc output for utilization and can include inverters and converters to change stored energy into electrical energy.

Energy Storage System, Self-Contained. Energy storage systems where the components such as cells, batteries, or modules and any necessary controls, ventilation, illumination, fire suppression, or alarm systems are assembled, installed, and packaged into a singular energy storage container or unit.

Informational Note: Self-contained systems will generally be manufactured by a single entity, tested and listed to safety standards relevant to the system, and readily connected on site to the electrical system and in the case of multiple systems to each other.

Energy Storage System, Pre-Engineered of Matched Components. Energy storage systems that are not self-contained systems but instead are pre-engineered and field-assembled using separate components supplied as a system by a singular entity that are matched and intended to be assembled as an energy storage system at the system installation site.

Informational Note: Pre-engineered systems of matched components for field assembly as a system will generally be designed by a single entity and comprised of components that are tested and listed separately or as an assembly.

Energy Storage System, Other. Energy storage systems that are not self-contained or pre-engineered systems of matched components but instead are composed of individual components assembled as a system.

Informational Note: Other systems will generally be comprised of different components combined on site to create an ESS. Those components would generally be tested and listed to safety standards relevant to the application.

Flow Battery. An energy storage component similar to a fuel cell that stores its active materials in the form of two electrolytes external to the reactor interface. When in use, the electrolytes are transferred between reactor and storage tanks.

Informational Note: Two commercially available flow battery technologies are zinc bromine and vanadium redox, sometimes referred to as pumped electrolyte ESS.

Intercell Connector. An electrically conductive bar or cable used to connect adjacent cells.

Intertier Connector. In a battery system, an electrical conductor used to connect two cells on different tiers of the same rack or different shelves of the same rack.

Inverter Input Circuit. Conductors between the inverter and the ESS in stand-alone and multimode inverter systems.

Inverter Output Circuit. Conductors between the inverter and another electric power production source, such as a utility for an electrical production and distribution network.

Inverter Utilization Output Circuit. Conductors between the multimode or standalone inverter and utilization equipment.

Nominal Voltage (Battery or Cell). The value assigned to a cell or battery of a given voltage class for the purpose of convenient designation. The operating voltage of the cell or battery may vary above or below this value.

Sealed Cell or Battery. A cell or battery that has no provision for the routine addition of water or electrolyte or for external measurement of electrolyte specific gravity.

Informational Note: Some cells that are considered to be sealed under conditions of normal use, such as valve-regulated lead-acid or some lithium cells, contain pressure relief valves.

Terminal. That part of a cell, container, or battery to which an external connection is made (commonly identified as a post, pillar, pole, or terminal post).

Wherever the requirements of other articles of this Code and Article 706 differ, the requirements of Article 706 shall apply. If the ESS is capable of being operated in parallel with a primary source(s) of electricity, the requirements in 705.6, 705.12, 705.14, 705.16, 705.32, 705.40, 705.100, 705.143, and Part IV of Article 705 shall apply.
ESS shall be classified as one of the types described as follows:
  1. ESS, self-contained

    Informational Note: Some self-contained systems may be listed.

  2. ESS, pre-engineered of matched components
  3. ESS, other
Monitors, controls, switches, fuses, circuit breakers, power conversion systems, inverters and transformers, energy storage components, and other components of the energy storage system other than lead-acid batteries, shall be listed. Alternatively, self-contained ESS shall be listed as a complete energy storage system.
Multiple ESSs shall be permitted to be installed in or on a single building or structure.
A disconnecting means shall be provided for all ungrounded conductors derived from an ESS. A disconnecting means shall be readily accessible and located within sight of the ESS.

Informational Note: See 240.21(H) for information on the location of the overcurrent device for conductors.

Where controls to activate the disconnecting means of an ESS are not located within sight of the system, the disconnecting means shall be capable of being locked in the open position, in accordance with 110.25, and the location of the controls shall be field marked on the disconnecting means.
Where a dc busway system is installed, the disconnecting means shall be permitted to be incorporated into the busway.
The disconnecting means shall be legibly marked in the field. The marking shall meet the requirements of 110.21(B) and shall include the following:
  1. Nominal ESS voltage
  2. Maximum available short-circuit current derived from the ESS
  3. The associated clearing time or arc duration based on the available short-circuit current from the ESS and associated overcurrent protective devices if applicable
  4. Date the calculation was performed

Exception: The labeling in 706.7(D)(1) through (D)(4) shall not be required if an arc flash label is applied in accordance with acceptable industry practice.

Informational Note No. 1: Industry practices for equipment labeling are described in NFPA 70E -2015, Standard for Electrical Safety in the Workplace. This standard provides specific criteria for developing arc-flash labels for equipment that provides nominal system voltage, incident energy levels, arc-flash boundaries, minimum required levels of personal protective equipment, and so forth.

Informational Note No. 2: Battery equipment suppliers can provide information about short-circuit current on any particular battery model.

Where energy storage system input and output terminals are more than 1.5 m (5 ft) from connected equipment, or where the circuits from these terminals pass through a wall or partition, the installation shall comply with the following:
  1. A disconnecting means shall be provided at the energy storage system end of the circuit. Fused disconnecting means or circuit breakers shall be permitted to be used.
  2. A second disconnecting means located at the connected equipment shall be installed where the disconnecting means required by 706.7(E)(1) is not within sight of the connected equipment.

    Informational Note No. 1: For remote disconnect controls in information technology equipment rooms, see 645.10.

    Informational Note No. 2: For overcurrent protection of batteries, see 240.21(H).

  3. Where fused disconnecting means are used, the line terminals of the disconnecting means shall be connected toward the energy storage system terminals.
  4. Disconnecting means shall be permitted to be installed in energy storage system enclosures where explosive atmospheres can exist if listed for hazardous locations.
  5. Where the disconnecting means in (1) is not within sight of the disconnecting means in (2), placards or directories shall be installed at the locations of all disconnecting means indicating the location of all other disconnecting means.
Connection to other energy sources shall comply with the requirements of 705.12.
A load disconnect that has multiple sources of power shall disconnect all energy sources when in the off position.
Only inverters and ac modules listed and identified as interactive shall be permitted on interactive systems.
Upon loss of primary source, an ESS with a utility interactive inverter shall comply with the requirements of 705.40.
Unbalanced connections between an energy storage system and electric power production sources shall be in accordance with 705.100.
The point of connection between an energy storage system and electric power production sources shall be in accordance with 705.12.
Provisions appropriate to the energy storage technology shall be made for sufficient diffusion and ventilation of any possible gases from the storage device, if present, to prevent the accumulation of an explosive mixture. A pre-engineered or self-contained ESS shall be permitted to provide ventilation in accordance with the manufacturer's recommendations and listing for the system.

Informational Note No. 1: See NFPA 1-2015, Fire Code, Chapter 52, for ventilation considerations for specific battery chemistries.

Informational Note No. 2: Some storage technologies do not require ventilation.

Informational Note No. 3: A source for design of ventilation of battery systems is IEEE 1635-2012/ASHRAE Guideline 21-2012 Guide for the Ventilation and Thermal Management of Batteries for Stationary Applications, and the UBC.

Informational Note No. 4: Fire protection considerations are addressed in NFPA 1-2015, Fire Code.

Guarding of live parts shall comply with 110.27.
Spaces about the ESS shall comply with 110.26. Working space shall be measured from the edge of the ESS modules, battery cabinets, racks, or trays. For battery racks, there shall be a minimum clearance of 25 mm (1 in.) between a cell container and any wall or structure on the side not requiring access for maintenance. ESS modules, battery cabinets, racks, or trays shall be permitted to contact adjacent walls or structures, provided that the battery shelf has a free air space for not less than 90 percent of its length. Pre-engineered and self-contained ESSs shall be permitted to have working space between components within the system in accordance with the manufacturer's recommendations and listing of the system.

Informational Note: Additional space is often needed to accommodate ESS equipment hoisting equipment, tray removal, or spill containment.

A personnel door(s) intended for entrance to and egress from rooms designated as ESS rooms shall open in the direction of egress and shall be equipped with listed panic hardware.
Illumination shall be provided for working spaces associated with ESS and their equipment and components. Luminaires shall not be controlled by automatic means only. Additional luminaires shall not be required where the work space is illuminated by an adjacent light source. The location of luminaires shall not do either of the following:
  1. Expose personnel to energized system components while performing maintenance on the luminaires in the system space
  2. Create a hazard to the system or system components upon failure of the luminaire
ESS shall be indicated by 706.11(A) and (B). The markings or labels shall be in accordance with 110.21(B).
A permanent plaque or directory denoting all electric power sources on or in the premises shall be installed at each service equipment location and at locations of all electric power production sources capable of being interconnected.

Exception: Installations with large numbers of power production sources shall be permitted to be designated by groups.

Any structure or building with an ESS that is not connected to a utility service source and is a stand-alone system shall have a permanent plaque or directory installed on the exterior of the building or structure at a readily visible location acceptable to the authority having jurisdiction. The plaque or directory shall indicate the location of system disconnecting means and that the structure contains a stand-alone electrical power system.

Part II Circuit Requirements

The maximum current for the specific circuit shall be calculated in accordance with 706.20(A)(1) through (A)(5).
The nameplate(s)-rated circuit current shall be the rated current indicated on the ESS nameplate(s) or system listing for pre-engineered or self-contained systems of matched components intended for field assembly as a system.
The maximum current shall be the inverter continuous output current rating.
The maximum current shall be the continuous inverter input current rating when the inverter is producing rated power at the lowest input voltage.
The maximum current shall be the continuous inverter output current rating when the inverter is producing rated power at the lowest input voltage.
The maximum current shall be the dc-to-dc converter continuous output current rating.
The ampacity of the feeder circuit conductors from the ESS(s) to the wiring system serving the loads to be serviced by the system shall not be less than the greater of the (1) nameplate(s) rated circuit current as determined in accordance with 706.20(A) or (2) the rating of the ESS(s) overcurrent protective device(s).
If the output of a single-phase, 2-wire ESS output(s) is connected to the grounded or neutral conductor and a single ungrounded conductor of a 3-wire system or of a 3-phase, 4-wire, wye-connected system, the maximum unbalanced neutral load current plus the ESS(s) output rating shall not exceed the ampacity of the grounded or neutral conductor.
ESS circuit conductors shall be protected in accordance with the requirements of Article 240. Protection devices for ESS circuits shall be in accordance with the requirements of 706.21(B) through (F). Circuits shall be protected at the source from overcurrent.
Overcurrent protective devices, where required, shall be rated in accordance with Article 240 and the rating provided on systems serving the ESS and shall be not less than 125 percent of the maximum currents calculated in 706.20(A).
Overcurrent protective devices, either fuses or circuit breakers, used in any dc portion of an ESS shall be listed and for dc and shall have the appropriate voltage, current, and interrupting ratings for the application.
A listed and labeled current-limiting overcurrent protective device shall be installed adjacent to the ESS for each dc output circuit.

Exception: Where current-limiting overcurrent protection is provided for the dc output circuits of a listed ESS, additional current-limiting overcurrent devices shall not be required.

Means shall be provided to disconnect any fuses associated with ESS equipment and components when the fuse is energized from both directions and is accessible to other than qualified persons. Switches, pullouts, or similar devices that are rated for the application shall be permitted to serve as a means to disconnect fuses from all sources of supply.
Where ESS input and output terminals are more than 1.5 m (5 ft) from connected equipment, or where the circuits from these terminals pass through a wall or partition, overcurrent protection shall be provided at the ESS.
Provisions shall be provided to control the charging process of the ESS. All adjustable means for control of the charging process shall be accessible only to qualified persons.

Informational Note: Certain types of energy storage equipment such as valve-regulated lead acid or nickel cadmium can experience thermal failure when overcharged.

An ESS employing a diversion charge controller as the sole means of regulating charging shall be equipped with a second independent means to prevent overcharging of the storage device.
Circuits containing a diversion charge controller and a diversion load shall comply with the following:
  1. The current rating of the diversion load shall be less than or equal to the current rating of the diversion load charge controller. The voltage rating of the diversion load shall be greater than the maximum ESS voltage. The power rating of the diversion load shall be at least 150 percent of the power rating of the charging source.
  2. The conductor ampacity and the rating of the overcurrent device for this circuit shall be at least 150 percent of the maximum current rating of the diversion charge controller.
Systems using utility-interactive inverters to control energy storage state-of-charge by diverting excess power into the utility system shall comply with 706.23(B)(3)(a) and (B)(3)(b).

(a) These systems shall not be required to comply with 706.23(B)(2).

(b) These systems shall have a second, independent means of controlling the ESS charging process for use when the utility is not present or when the primary charge controller fails or is disabled.

Where charge controllers and other DC-to-DC power converters that increase or decrease the output current or output voltage with respect to the input current or input voltage are installed, all of the following shall apply:
  1. The ampacity of the conductors in output circuits shall be based on the maximum rated continuous output current of the charge controller or converter for the selected output voltage range.
  2. The voltage rating of the output circuits shall be based on the maximum voltage output of the charge controller or converter for the selected output voltage range.

Part III Electrochemical Energy Storage Systems

Part III of this article applies to ESSs that are comprised of sealed and non-sealed cells or batteries or system modules that are comprised of multiple sealed cells or batteries that are not components within a listed product.

Informational Note: An energy storage component, such as batteries, that are integrated into a larger piece of listed equipment, such as an uninterruptible power supply (UPS), are examples of components within a listed product.

An ESS for dwelling units shall not exceed 100 volts between conductors or to ground.

Exception: Where live parts are not accessible during routine ESS maintenance, an ESS voltage exceeding 100 volts shall be permitted.

Battery circuits subject to field servicing, where exceeding 240 volts nominal between conductors or to ground, shall have provisions to disconnect the series-connected strings into segments not exceeding 240 volts nominal for maintenance by qualified persons. Non-load-break bolted or plug-in disconnects shall be permitted.
ESS exceeding 100 volts between conductors or to ground shall have a disconnecting means, accessible only to qualified persons, that disconnects ungrounded and grounded circuit conductor(s) in the electrical storage system for maintenance. This disconnecting means shall not disconnect the grounded circuit conductor(s) for the remainder of any other electrical system. A non-load-break-rated switch shall be permitted to be used as a disconnecting means.
On ESS exceeding 100 volts between the conductors or to ground, the battery circuits shall be permitted to operate with ungrounded conductors, provided a ground-fault detector and indicator is installed to monitor for ground faults within the storage system.
Antioxidant material suitable for the battery connection shall be used when recommended by the battery or cell manufacturer.

Informational Note: The battery manufacturer's installation and instruction manual can be used for guidance for acceptable materials.

The ampacity of field-assembled intercell and intertier connectors and conductors shall be of such cross-sectional area that the temperature rise under maximum load conditions and at maximum ambient temperature shall not exceed the safe operating temperature of the conductor insulation or of the material of the conductor supports.

Informational Note: Conductors sized to prevent a voltage drop exceeding 3 percent of maximum anticipated load, and where the maximum total voltage drop to the furthest point of connection does not exceed 5 percent, may not be appropriate for all battery applications. IEEE 1375-2003, Guide for the Protection of Stationary Battery Systems, provides guidance for overcurrent protection and associated cable sizing.