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Section E3702 Branch Circuit Ratings
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The voltage
ratings of branch circuits that supply luminaires or receptacles
for cord-and-plug-connected loads of up to 1,400 voltamperes
or of less than 1/4 horsepower (0.186 kW) shall be
limited to a maximum rating of 120 volts, nominal, between
conductors.
Branch circuits that supply cord-and-plug-connected or permanently connected utilization equipment and appliances rated at over 1,440 volt-amperes or 1/4 horsepower (0.186 kW) and greater shall be rated at 120 volts or 240 volts, nominal. [210.6(A), (B), and (C)]
Branch circuits that supply cord-and-plug-connected or permanently connected utilization equipment and appliances rated at over 1,440 volt-amperes or 1/4 horsepower (0.186 kW) and greater shall be rated at 120 volts or 240 volts, nominal. [210.6(A), (B), and (C)]
Branch circuits shall
be rated in accordance with the maximum allowable ampere
rating or setting of the overcurrent protection device. The rating
for other than individual branch circuits shall be 15, 20, 30,
40 and 50 amperes. Where conductors of higher ampacity are
used, the ampere rating or setting of the specified over-current
device shall determine the circuit rating. (210.3)
A 15- or
20-ampere branch circuit shall be permitted to supply lighting
units, or other utilization equipment, or a combination of
both. The rating of any one cord-and-plug-connected utilization
equipment not fastened in place shall not exceed 80 percent
of the branch-circuit ampere rating. The total rating of
utilization equipment fastened in place, other than luminaires,
shall not exceed 50 percent of the branch-circuit ampere rating
where lighting units, cord-and-plug-connected utilization
equipment not fastened in place, or both, are also supplied.
[210.23(A)(1) and (2)]
General-purpose branch circuits shall supply lighting outlets,
appliances, equipment or receptacle outlets, and combinations
of such. Multioutlet branch circuits serving lighting or
receptacles shall be limited to a maximum branch-circuit rating
of 20 amperes. [210.23(A), (B), and (C)]
Branchcircuit
conductors supplying a single motor shall have an
ampacity not less than 125 percent of the motor full-load current
rating. [ 430.22(A)]
For circuits supplying loads consisting
of motor-operated utilization equipment that is fastened in
place and that has a motor larger than 1/8 horsepower (0.093
kW) in combination with other loads, the total calculated load
shall be based on 125 percent of the largest motor load plus
the sum of the other loads. [220.18(A)]
For circuits supplying luminaires having ballasts or LED drivers,
the calculated load shall be based on the total ampere ratings
of such units and not on the total watts of the lamps.
[220.18(B)]
It shall be permissible to calculate the branch-circuit
load for one range in accordance with Table E3704.2(2).
The branch-circuit load for one wall-mounted oven or one
counter-mounted cooking unit shall be the nameplate rating
of the appliance. The branch-circuit load for a countermounted
cooking unit and not more than two wall-mounted
ovens all supplied from a single branch circuit and located in
the same room shall be calculated by adding the nameplate
ratings of the individual appliances and treating the total as
equivalent to one range. (220.55 Note 4)
Ranges
with a rating of 8.75 kV A or more shall be supplied by a
branch circuit having a minimum rating of 40 amperes.
[210.19(A)(3)]
Electric
space-heating and water-heating appliances shall be considered
to be continuous loads. Branch circuits supplying two or
more outlets for fixed electric space-heating equipment shall
be rated 15, 20, 25 or 30 amperes. [424.3(A)]
A room air conditioner shall be considered as a single motor
unit in determining its branch-circuit requirements where all
the following conditions are met:
- It is cord- and attachment plug-connected.
- The rating is not more than 40 amperes and 250 volts; single phase.
- Total rated-load current is shown on the room air-conditioner nameplate rather than individual motor currents.
- The rating of the branch-circuit short-circuit and ground-fault protective device does not exceed the ampacity of the branch-circuit conductors, or the rating of the branch-circuit conductors, or the rating of the receptacle, whichever is less. [ 440.62(A)]
The
total marked rating of a cord- and attachment plug-connected
room air conditioner shall not exceed 80 percent of
the rating of a branch circuit where no other appliances are
also supplied. [440.62(B)]
The total marked rating of a cord- and
attachment plug-connected room air conditioner shall not
exceed 50 percent of the rating of a branch circuit where
lighting or other appliances are also supplied. Where the
circuitry is interlocked to prevent simultaneous operation
of the room air conditioner and energization of other outlets
on the same branch circuit, a cord- and attachment plug-connected room air conditioner shall not exceed 80
percent of the branch-circuit rating. [440.62(C)]
Outlets installed
for the purpose of charging electric vehicles shall be supplied
by a separate branch circuit. Such circuit shall not supply
other outlets. (210.17)
The
requirements for circuits having two or more outlets, or
receptacles, other than the receptacle circuits of Sections
E3703.2, E3703.3 and E3703.4, are summarized in Table
E3702.14. Branch circuits in dwelling units shall supply only
loads within that dwelling unit or loads associated only with
that dwelling unit. Branch circuits installed for the purpose of
lighting, central alarm, signal, communications or other purposes
for public or common areas of a two-family dwelling
shall not be supplied from equipment that supplies an individual
dwelling unit. (210.24 and 210.25)
| CIRCUIT RATING | |||
|---|---|---|---|
| 15 amp | 20 amp | 30 amp | |
Conductors: Minimum size (AWG) circuit conductors |
14 | 12 | 10 |
Maximum overcurrent- protection device rating Ampere rating |
15 | 20 | 30 |
Outlet devices: Lampholders permitted Receptacle rating (amperes) |
Any type 15 maximum | Any type 15 or 20 | N/A 30 |
| Maximum load (amperes) | 15 | 20 | 30 |
- These gages are for copper conductors.
- N/A means not allowed.
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