NABCEP PV System Inspector Flashcards

What is the purpose of verifying the PV system's maximum system voltage during an inspection?

Answer: To confirm that all system components (wiring, inverters, disconnects, modules) are rated for the maximum DC voltage the system can produce

Maximum system voltage (calculated under lowest expected temperature conditions) must not exceed the voltage rating of any component; exceeding ratings risks insulation failure, fire, or equipment damage.

An inspector finds that MC4 connectors from two different manufacturers have been mismated (cross-mated) in a PV system. What is the concern?

Answer: Cross-mating connectors from different manufacturers can cause arc faults, increased resistance, and connector failure as they are not tested together

MC4-style connectors from different manufacturers may not mate reliably, creating hot spots, arc faults, and potential fire hazards; NEC 690.33(C) requires compatible connectors from the same manufacturer.

What is the inspector checking when verifying the 'AC disconnect within sight of the inverter' requirement?

Answer: That a listed disconnect means is installed within sight of (visible from and within 50 feet of) the inverter per NEC 690.15

NEC 690.15 requires a means to disconnect the inverter from all ungrounded conductors within sight of the inverter, defined as visible and within 50 feet, to allow safe servicing.

During inspection, a utility-interactive inverter is installed without anti-islanding protection certification. Why is this a code and safety concern?

Answer: An inverter without certified anti-islanding protection can continue energizing utility lines during an outage, endangering utility workers

Anti-islanding protection automatically disconnects the inverter from the grid during an outage, preventing it from back-feeding live voltage onto lines that utility workers assume are de-energized.

What must an inspector verify regarding the PV system's interconnection with the utility service panel to ensure NEC 705 compliance?

Answer: The sum of breaker ampere ratings on a busbar does not exceed 120% of the busbar's ampere rating (120% rule) when the solar breaker is at the opposite end from the main breaker

NEC 705.12(B) allows the supply-side connection via the 120% rule: the sum of the main breaker and solar breaker must not exceed 120% of the busbar rating, and the solar breaker must be at the opposite end.

An inspector finds the required PV system disconnecting means is not accessible without a ladder and is located 15 feet above finished grade on a commercial building wall. Is this compliant?

Answer: No, NEC 690.13 generally requires disconnects to be readily accessible and NEC 240.24 limits service disconnects to within 6.5 feet of finished grade unless exceptions apply

Disconnecting means must be readily accessible per NEC, and heights above 6.5 feet are generally not considered readily accessible unless specific exceptions for qualified-person-only areas apply.