690.31 Methods Permitted.
(A) 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.
Where photovoltaic source and output circuits operating at maximum system voltages greater than 30 volts are installed in readily accessible locations, circuit conductors shall be installed in a raceway.
FPN: Photovoltaic modules operate at elevated temperatures when exposed to high ambient temperatures and to bright sunlight. These temperatures may routinely exceed 70?C (158?F) in many locations. Module interconnection conductors are available with insulation rated for wet locations and a temperature rating of 90?C (194?F) or greater.
(B) Single-Conductor Cable. Single-conductor cable type USE-2, and single-conductor cable listed and labeled as photovoltaic (PV) wire shall be permitted in exposed outdoor locations in photovoltaic source circuits for photovoltaic module interconnections within the photovoltaic array.
Exception: Raceways shall be used when required by 690.31(A).
(C) 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).
Table 690.31(C) Correction Factors
Temperature Rating of Conductor
Ambient Temperature
(?C) 60?C (140?F) 75?C (167?F) 90?C (194?F) 105?C (221?F) Ambient Temperature
(?F)
30 1.00 1.00 1.00 1.00 86
31?35 0.91 0.94 0.96 0.97 87?95
36?40 0.82 0.88 0.91 0.93 96?104
41?45 0.71 0.82 0.87 0.89 105?113
46?50 0.58 0.75 0.82 0.86 114?122
51?55 0.41 0.67 0.76 0.82 123?131
56?60 ? 0.58 0.71 0.77 132?140
61?70 ? 0.33 0.58 0.68 141?158
71?80 ? ? 0.41 0.58 159?176
(D) 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 module 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.
(E) 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 metal raceways, or metal 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 comply with 690.14(A) through (D).
(F) Flexible, Fine-Stranded Cables. Flexible, fine-stranded cables shall be terminated only with terminals, lugs, devices, or connectors that are identified and listed for such use.
