690.31(C) Cables.

This UL Listed PV wire complies with the change in 690.31(C)(1). Be sure to use it within the array or plan on putting it in a raceway where it leaves the array.
Click to Enlarge
This UL Listed PV wire complies with the change in 690.31(C)(1). Be sure to use it within the array or plan on putting it in a raceway where it leaves the array.

Code Change Summary: Revised code language on the conductor and cable types permitted for PV systems.

In the 2020 NEC®, the language pertaining to single and multiconductor cables used in PV systems was cleaned up and expanded for usability. One main principle still remains for single-conductor cables: If a single-conductor DC PV cable is installed in exposed outdoor locations, it must be “within the PV array”.

A common code violation occurs when single-conductor PV cables extend without a raceway beyond the envelope of the PV array (see image).

The rules on multiconductor jacketed cables have been expanded and include several options for those cables that have a stand-alone listing but are not listed as an overall PV assembly.

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 2020 NEC® edition of NFPA 70.

2017 Code Language:

690.31(C) Single-Conductor Cable.

(1) General. Single-conductor cable Type USE-2 and single conductor cable listed and identified as photovoltaic (PV) wire shall be permitted in exposed outdoor locations in PV source circuits within the PV array. PV wire shall be installed in accordance with 338.10(B)(4)(b) and 334.30.

690.31(D) Multiconductor Cable. Jacketed multiconductor cable assemblies listed and identified for the application shall be permitted in outdoor locations. The cable shall be secured at intervals not exceeding 1.8 m (6 ft).

2020 Code Language:

690.31(C) Cables. Type PV wire or cable and Type distributed generation (DG) cable shall be listed.

N (1) Single-Conductor Cable. Single-conductor cable in exposed outdoor locations in PV system dc circuits within the PV array shall be permitted to be one of the following:

(1) PV wire or cable

(2) Single-conductor cable marked sunlight resistant and Type USE-2 and Type RHW-2

Exposed cables shall be supported and secured at intervals not to exceed 600 mm (24 in.) by cable ties, straps, hangers, or similar fittings listed and identified for securement and support in outdoor locations. PV wire or cable shall be permitted in all locations where RHW-2 is permitted

Exception: PV systems meeting the requirements of 691.4 shall be permitted to have support and securement intervals as defined in the engineered design.

(3) Multiconductor Jacketed Cables. Where part of a listed PV assembly, multiconductor jacketed cables shall be installed in accordance with the included instructions. Where not part of a listed assembly, or where not otherwise covered in this Code, multiconductor jacketed cables, including DG cable, shall be installed in accordance with the product listing and shall be permitted in PV systems. These cables shall be installed in accordance with the following:

(1) In raceways, where on or in buildings other than rooftops

(2) Where not in raceways, in accordance with the following:

  1. Marked sunlight resistant in exposed outdoor locations
  2. Protected or guarded, where subject to physical damage
  3. Closely follow the surface of support structures
  4. Secured at intervals not exceeding 1.8 m (6 ft)
  5. Secured within 600 mm (24 in.) of mating connectors or entering enclosures
  6. f. Marked direct burial, where buried in the earth

Did You Like This? Let Us Know With A Like! Thanks!

690.31(C) Cables.

Below is a Real Question from our Electrical Continuing Education Courses for Electrical License Renewal:

Which of the following is true of cables used in a PV system?

A: Type USE-2 wire can be used as single-conductor cable in exposed outdoor locations in PV system dc circuits where venturing outside of the array with no additional protection.
B: Type PV wire can be used as single-conductor cable in exposed outdoor locations in PV system dc circuits where venturing outside of the array with no additional protection.
C: Type PV wire can be used as single-conductor cable in exposed outdoor locations in PV system dc circuits within the PV array.
D: Type RHW-2 wire can be used as single-conductor cable in exposed outdoor locations in PV system dc circuits where venturing outside of the array with no additional protection.
Please register or sign in for electrical continuing education courses.

If you were already signed in, your session probably expired, please sign back in.