690.31(A) Wiring Systems.
Code Change Summary: A new wiring method and a new table was added to section 690.31.
In the 2014 NEC®, PV source and output circuits installed in readily accessible locations and operating at maximum system voltages greater than 30 volts were required to be guarded or installed in a raceway. To understand and apply the requirement, the following two circumstances must be present:
- The PV source and output circuits are installed where readily accessible which means capable of being reached quickly for operation, renewal, or inspections without requiring those to whom ready access is requisite to take actions such as to use tools (other than keys), to climb over or under, to remove obstacles, or to resort to portable ladders, and so forth.
- The PV source and output circuits operate at maximum system voltages greater than 30 volts which is almost always the case for typical PV systems.
The same rules still apply but another option was added in the 2017 NEC®. Type MC cable is now permitted to be used as a method to enclose the above PV system conductors. This new code language was added to align with similar requirements in 690.31(G) pertaining to PV System DC circuits on or in a building.
As well, new Table 690.31(A) is now required to be used for conductor ambient temperature correction where conductors are installed in areas where the temperature exceeds 30°C (86°F).
Below is a preview of the NEC®. See the actual NEC® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2017 NEC® edition of NFPA 70.
2014 Code Language:
690.31 Methods Permitted.
(A) Wiring Systems. All raceway and cable wiring methods included in this Code, other wiring systems and fittings specifically listed for use on PV arrays, and wiring as part of a listed system shall be permitted. Where wiring devices with integral enclosures are used, sufficient length of cable shall be provided to facilitate replacement.
Where PV source and output circuits operating at maximum system voltages greater than 30 volts are installed in readily accessible locations, circuit conductors shall be guarded or installed in a raceway.
2017 Code Language:
690.31 Methods Permitted.
(A) Wiring Systems. All raceway and cable wiring methods included in this Code, other wiring systems and fittings specifically listed for use on PV arrays, and wiring as part of a listed system shall be permitted. Where wiring devices with integral enclosures are used, sufficient length of cable shall be provided to facilitate replacement.
Where PV source and output circuits operating at voltages greater than 30 volts are installed in readily accessible locations, circuit conductors shall be guarded or installed in Type MC cable or in raceway. For ambient temperatures exceeding 30°C (86°F), conductor ampacities shall be corrected in accordance with Table 690.31(A).