NABCEP NABCEP PV System Inspector 2 — Questions and Answers
Question 1: What wire gauge and color coding issue is a common code violation found during PV system inspections?
- Using copper conductors for DC circuits
- Using white or gray conductors for ungrounded DC positive conductors without marking them with the correct polarity color (Correct answer)
- Using conduit instead of raceways
- Using aluminum conductors for branch circuits
Correct answer: Using white or gray conductors for ungrounded DC positive conductors without marking them with the correct polarity color
NEC 690.31(B) requires that conductors not of the required color be permanently re-identified with colored tape, paint, or marking at each end; white conductors used as positive DC conductors must be re-marked.
Question 2: During an inspection, a roof-mounted PV system has modules installed with less than the required setback from the roof edge. What code is most likely violated?
- NEC 690.12 rapid shutdown
- IFC 605.11 or equivalent local fire code requiring access pathways and setbacks for firefighter access (Correct answer)
- NEC 690.4 general installation
- NFPA 70E arc flash standard
Correct answer: IFC 605.11 or equivalent local fire code requiring access pathways and setbacks for firefighter access
International Fire Code and local fire codes specify minimum setbacks from roof edges, ridges, and hips to ensure firefighter access and ventilation paths on residential roofs.
Question 3: An inspector notes that the PV inverter is installed in a location where ambient temperature regularly exceeds the inverter's rated operating temperature range. What is the concern?
- The inverter will charge the battery too fast
- The inverter will derate output or fail prematurely due to thermal stress, and is not installed per manufacturer specifications (Correct answer)
- The inverter will overproduce energy
- Higher temperatures improve inverter efficiency
Correct answer: The inverter will derate output or fail prematurely due to thermal stress, and is not installed per manufacturer specifications
Inverters installed outside their rated ambient temperature range will derate power output or experience premature failure; installations must comply with manufacturer temperature specifications.
Question 4: What does the inspector verify when checking the PV system's grounding and bonding?
- That all modules are grounded to the roof structure only
- That all equipment is bonded to a common grounding electrode system per NEC Article 250 and 690 (Correct answer)
- That only the inverter is grounded
- That the DC negative conductor serves as the grounding conductor
Correct answer: That all equipment is bonded to a common grounding electrode system per NEC Article 250 and 690
NEC requires all metallic equipment, racking, and enclosures to be bonded together and connected to a grounding electrode system that meets both Article 250 and Article 690 requirements.
Question 5: When inspecting a battery energy storage system added to an existing PV system, which code document governs the installation requirements?
- NEC 690 only
- Both NEC 706 (energy storage) and NFPA 855, in addition to NEC 690 for the PV portions (Correct answer)
- Only the battery manufacturer's manual
- Only local building code, not NEC
Correct answer: Both NEC 706 (energy storage) and NFPA 855, in addition to NEC 690 for the PV portions
ESS installations must comply with NEC 706 for electrical requirements, NFPA 855 for fire and life safety, and NEC 690 for PV interconnection portions.
Question 6: An inspector observes that a rooftop PV system's equipment grounding conductors (EGCs) are connected using standard steel sheet metal screws into racking. Is this acceptable?
- Yes, any steel fastener is acceptable for bonding
- No, EGC bonding connections must use listed bonding hardware designed to penetrate anodized or painted surfaces and maintain a reliable connection (Correct answer)
- Yes, as long as the screws are coated
- Yes, for residential systems under 10 kW
Correct answer: No, EGC bonding connections must use listed bonding hardware designed to penetrate anodized or painted surfaces and maintain a reliable connection
Standard sheet metal screws do not reliably penetrate anodized aluminum or painted surfaces to make a code-compliant bond; listed bonding hardware (e.g., Weeb clips, bonding washers) must be used.
NABCEP NABCEP PV System Inspector 2
What wire gauge and color coding issue is a common code violation found during PV system inspections?