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Wiring Methods
Methods Permitted.
Wiring Systems. All raceway and cable wiring methods included in this Code and other wiring systems and fittings specifically intended and identified for use on photovoltaic arrays shall be permitted. where wiring devices with integral enclosures are used, sufficient length of cable shall be provided to facilitate replacement.
Single-Conductor Cable. Types SE, UF, USE, and USE-2 single-conductor cable shall be permitted in photovoltaic source circuits where installed in the same manner as a Type UF multiconductor cable in accordance with Part II of Article 340. Where exposed to sunlight, Type UF cable identified as sunlight-resistant shall be used.
Flexible Cords and Cables. Flexible cords and cables, where used to connect the moving parts of tracking PV modules, shall comply with Article 400 and shall be of a type identified as a hard-service cord or portable power cable; they shall be suitable for extra-hard usage, listed for outdoor use, water resistant, and sunlight resistant. Allowable ampacities shall be in accordance with 400.5. For ambient temperatures exceeding 30°C (86°F), the ampacities shall be derated by the appropriate factors given in Table 690.31(C).
Small-Conductor Cables. Single-conductor cables listed for outdoor use that are sunlight resistant and moisture resistant in sizes 16 AWG and 18 AWG shall be permitted for modules interconnections where such cables meet the ampacity requirements of 690.8. Section 310.15 shall be used to determine the cable ampacity and temperature derating factors.
Direct-Current Photovoltaic Source and Output Circuits Inside a Building. Where direct current photovoltaic source or output circuits of a utility-interactive inverter from a building-integrated or other photovoltaic system are run inside a building or structure, they shall be contained in metallic raceways or enclosures from the point of penetration of the surface of the building or structure to the first readily accessible disconnecting means. The disconnecting means shall co9mply with 690.14(A) through 690.14(D).
Component Interconnections. Fittings and connectors that are intended to be concealed at the time of on-site assembly, where listed for such use, shall be permitted for on-site interconnection of modules or other array components. Such fittings and connectors shall be equal to the wiring method employed in insulation, temperature rise, and fault-current withstand, and shall be capable of resisting the effects of the environment in which they are used.
Connectors. The connectors permitted by Article 690 shall comply with 690.33(A) through 690.33(E).
Configuration. The connectors shall be polarized and shall have a configuration that is non-interchangeable with receptacles in other electrical systems on the premises.
Guarding. The connectors shall be constructed and installed so as to guard against inadvertent contact with live parts by persons.
Type. The connectors shall be of the latching or locking type.
Grounding Member. The grounding member shall be the first to make and the last to break contact with the mating connector.
Interruption of Circuit. The connectors shall be capable of interrupting the circuit current without hazard to the operator.
Access to Boxes. Junction, pull, and outlet boxes located behind modules or panels shall be so installed that the wiring contained in them can be rendered accessible directly or by displacement of a module(s) or panel(s) secured by removable fasteners and connected by a flexible wiring system.
Ungrounded Photovoltaic Power Systems. Photovoltaic power systems shall be permitted to operate with ungrounded photovoltaic source and output circuits where the system complies with the following.
Disconnects. All photovoltaic source and output circuits conductors shall have disconnects complying with 690 part III.
Overcurrent Protection. All photovoltaic source and output circuits conductors shall have overcurrent protection complying with 690.9.
Ground-Fault Protection
All photovoltaic source and output circuits shall be provided with a ground-fault protection device or system that complies with:
- Detects a ground fault.
- Indicates that a ground fault has occurred
- Automatically disconnects the conductors and/or shuts off the utility-interactive inverter or charge controller for that portion of the faulted array.
The photovoltaic source and output conducts shall consist of sheathed (jacketed) multi-conductor cables or shall be installed in a raceway.
The photovoltaic power system direct-current circuits shall ber permitted to be used with ungrounded battery systems complying with 690.71(G).
The photovoltaic power source shall be labeled with the following warning at each junction box, combiner box, disconnect, and device where the ungrounded circuits may be exposed during service:
WARNING
ELECTRIC SHOCK HAZARD. THE DIRECT
CURRENT CIRCUIT CONDUCTORS OF THIS
PHOTOVOLTAIC POWER SYSTEM ARE
UNGROUNDED BUT MAY BE ENERGIZED
WITH RESPECT TO GROUND DUE TO
LEAKAGE PATHS AND OR GROUND FAULTS.
The inverters or charge controllers used in systems with ungrounded photovoltaic source and output circuits shall be listed for the purpose.
Table 690.31(C) Correction Factors
| Ambient Temperature(°C) | Temperature Rating of Conductor | Ambient Temperature (°F) |
| 60°C (140°F) | 75°C (167°F) | 90°C (194°F) | 105°C (221°F) |
| 30 | 1.00 | 1.00 | 1.00 | 1.00 | 86 |
| 31-35 | .91 | .94 | .96 | .97 | 87-95 |
| 36-40 | .82 | .88 | .91 | .93 | 96-104 |
| 41-45 | .71 | .82 | .87 | .89 | 105-113 |
| 46-50 | .58 | .75 | .82 | .86 | 114-122 |
| 51-55 | .41 | .67 | .76 | .82 | 123-131 |
| 56-60 | -- | .58 | .71 | .77 | 132-140 |
| 61-70 | -- | .33 | .58 | .68 | 141-158 |
| 71-80 | -- | -- | .41 | .58 | 159-176 |
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