Article 830 Network-Powered Broadband Communications Systems
Informational Note: A typical basic system configuration includes a cable supplying power and broadband signal to a network interface unit that converts the broadband signal to the component signals. Typical cables are coaxial cable with both broadband signal and power on the center conductor, composite metallic cable with a coaxial member(s) or twisted pair members for the broadband signal and twisted pair members for power, and composite optical fiber cable with a pair of conductors for power. Larger systems may also include network components such as amplifiers that require network power.
Informational Note: A typical single-family network-powered communications circuit consists of a communications drop or communications service cable and an NIU and includes the communications utility's serving terminal or tap where it is not under the exclusive control of the communications utility.
Fault Protection Device. An electronic device that is intended for the protection of personnel and functions under fault conditions, such as network-powered broadband communications cable short or open circuit, to limit the current or voltage, or both, for a low-power network-powered broadband communications circuit and provide acceptable protection from electric shock.
Network Interface Unit (NIU). A device that converts a broadband signal into component voice, audio, video, data, and interactive services signals and provides isolation between the network power and the premises signal circuits. These devices often contain primary and secondary protectors.
Informational Note: A typical one-family dwelling networkpowered communications circuit consists of a communications drop or communications service cable and an NIU and includes the communications utility's serving terminal or tap where it is not under the exclusive control of the communications utility.
- Installations of communications circuits — Part IV of Article 805
- Installations of community antenna television and radio distribution circuits — Part V of Article 820
- Installations of optical fiber cables — Part V of Article 770
- Installations of Class 2 and Class 3 circuits — Part III of Article 725
- Installations of power-limited fire alarm circuits — Part III of Article 760
- Sources shall be classified as defined in Table 830.15.
- Direct-current power sources exceeding 150 volts to ground, but no more than 200 volts to ground, with the current to ground limited to 10 mA dc, that meet the current and power limitation for medium-power sources in Table 830.15 shall be classified as medium-power sources.
Informational Note: One way to determine compliance with 830.15(2) is listed information technology equipment intended to supply power via a communications network that complies with the requirements for RFT-V circuits as defined in UL 60950-21-2007, Standard for Safety for Information Technology Equipment — Safety — Part 21: Remote Power Feeding.
|Network Power Source||Low||Medium|
|Circuit voltage, Vmax (volts) 1||0—100||0—150|
|Power limitation, VAmax (volt-amperes)1||250||250|
|Current limitation, Imax (amperes)1||1000/Vmax||1000/Vmax|
|Maximum power rating (volt-amperes)||100||100|
|Maximum voltage rating (volts)||100||150|
|Maximum overcurrent 100 protection (amperes) 2||100/Vmax||NA|
|1 Vmax, Imax, and VAmax are determined with the current-limiting impedance in the circuit (not bypassed) as follows:|
|Vmax — Maximum system voltage regardless of load with rated input applied.|
|Imax — Maximum system current under any noncapacitive load, including short circuit, and with overcurrent protection bypassed if used. Imax limits apply after 1 minute of operation.|
|VAmax — Maximum volt-ampere output after 1 minute of operation regardless of load and overcurrent protection bypassed if used.|
|2 Overcurrent protection is not required where the current-limiting device provides equivalent current limitation and the current-limiting device does not reset until power or the load is removed.|
Exception: Outdoor community antenna television and radio distribution system coaxial cables installed prior to January 1, 2000, and installed in accordance with Article 820, shall be permitted for lowpower-type, network-powered broadband communications circuits.
- 2.9 m (91/2 ft) — above finished grade, sidewalks, or from any platform or projection from which they might be reached and accessible to pedestrians only
- 3.5 m (111/2 ft) — over residential property and driveways, and those commercial areas not subject to truck traffic
- 4.7 m (151/2 ft) — over public streets, alleys, roads, parking areas subject to truck traffic, driveways on other than residential property, and other land traversed by vehicles such as cultivated, grazing, forest, and orchard
Informational Note: These clearances have been specifically chosen to correlate with ANSI/IEEE C2-2012, National Electrical Safety Code, Table 232-1, which provides for clearances of wires, conductors, and cables above ground and roadways, rather than using the clearances referenced in 225.18. Because Article 805 and Article 820 have had no required clearances, the communications industry has used the clearances from the NESC for their installed cable plant.
Exception: Conductors run above the top level of a window shall be permitted to be less than the 900-mm (3-ft) requirement above.
Overhead (aerial) network-powered broadband communications cables shall not be installed beneath openings through which materials might be moved, such as openings in farm and commercial buildings, and shall not be installed where they obstruct entrance to these building openings.
Exception: Where a network-powered broadband communications cable does not have sufficient strength to be self-supporting, it shall be attached to a supporting messenger cable that, together with the attachment fixtures or supports, shall be acceptable for the purpose and shall have sufficient strength to withstand the loads to which they may be subjected.
Exception: A low-power network-powered broadband communications circuit that is equipped with a listed fault protection device, appropriate to the network-powered broadband communications cable used, and located on the network side of the network-powered broadband communications cable shall not be required to be additionally protected by enclosures, raceways, or other approved means.
(A) Underground Systems With Electric Light and Power, Class 1, or Non—Power-Limited Fire Alarm Circuit Conductors
Exception No. 2: Separation shall not be required where electric light or power branch-circuit or feeder conductors, non—power-limited fire alarm circuit conductors, or Class 1 circuit conductors are installed in a raceway or in metal-sheathed, metal-clad, or Type UF or Type USE cables; or the network-powered broadband communications cables have metal cable armor or are installed in a raceway.