NABCEP Code Requirements 4 — Questions and Answers
Question 1: Per NEC 690.9, overcurrent protection is NOT required for a PV source circuit conductor when:
- The conductor is rated at least 125% of the module Isc
- The conductor ampacity is greater than the maximum available fault current from all parallel sources (Correct answer)
- The conductor is protected by a GFPD only
- The circuit is under 50V DC
Correct answer: The conductor ampacity is greater than the maximum available fault current from all parallel sources
NEC 690.9(A) exception permits omitting OCPD when the conductor ampacity exceeds the maximum fault current available from parallel-connected sources.
Question 2: According to NEC 690.31(C), single-conductor cables used as PV wire in exposed outdoor locations shall be:
- Listed for use in wet locations and sunlight resistant (Correct answer)
- Installed in conduit at all times
- Rated at minimum 600V regardless of actual system voltage
- Protected from UV with a paint coating
Correct answer: Listed for use in wet locations and sunlight resistant
NEC 690.31(C) requires single-conductor PV wire to be listed for wet locations and sunlight resistant when installed outdoors.
Question 3: What is the maximum DC voltage permitted for commercial and utility-scale PV systems under NEC Article 690?
- 600V
- 1000V
- 1500V (Correct answer)
- 2000V
Correct answer: 1500V
NEC 690.7(A) permits PV systems up to 1500V DC for commercial and utility-scale installations using listed 1500V equipment.
Question 4: When a rooftop PV array is installed on a building with a hip roof, which code document specifies the required setback from the ridge?
- NEC Article 690
- IFC Section 605 / local fire codes (Correct answer)
- UL 2703
- IEEE 1547
Correct answer: IFC Section 605 / local fire codes
IFC Section 605 and local fire codes require specific setbacks from ridges, hips, and eaves to allow firefighter access.
Question 5: Under NEC 690.4(B), how many PV systems are permitted to be installed on or in a single building or structure?
- Only one system is permitted
- Up to two systems, one per service
- Multiple systems are permitted (Correct answer)
- Only systems under 10kW may be multiple
Correct answer: Multiple systems are permitted
NEC 690.4(B) explicitly permits multiple PV systems to be installed on a single building.
Question 6: Per NEC 690.11, arc-fault circuit protection (AFCI) for PV systems is required on DC circuits of PV systems operating at what voltage or greater on dwellings?
- 48V
- 80V (Correct answer)
- 120V
- 240V
Correct answer: 80V
NEC 690.11 requires DC arc-fault circuit protection on PV systems with circuits operating at 80V or greater on dwellings.
Question 7: According to NEC 690.43, equipment grounding conductors for PV systems shall be sized in accordance with:
- Table 250.122 based on the OCPD rating (Correct answer)
- Table 310.16 based on the conductor ampacity
- Table 690.9 based on module Isc
- Table 250.66 based on service entrance size
Correct answer: Table 250.122 based on the OCPD rating
NEC 690.43 requires PV equipment grounding conductors to be sized per Table 250.122 based on the rating of the overcurrent protective device.
NABCEP Code Requirements 4
Per NEC 690.9, overcurrent protection is NOT required for a PV source circuit conductor when: