CSLB C-46 Solar ContractorElectrical and Plumbing CodesEasy
A solar contractor is installing a new PV system on a residential property. The inverter has an AC output current of 30 A. According to NEC 690.8(A)(1), what is the minimum required continuous current rating for the PV inverter AC output circuit conductors, assuming no temperature correction or adjustment factors are needed?
- A50 A
- B30 A
- C37.5 A
- D45 A
Show answer & explanationAnswer & explanation
Correct answer: C. 37.5 A
NEC 690.8(A)(1) requires that the conductors for a PV inverter AC output circuit be sized for a continuous current of not less than 125% of the maximum inverter output current. Therefore, 30 A * 1.25 = 37.5 A.
Why the other options are wrong
- A. This value is significantly higher than the minimum required rating.
- B. This is the actual output current, not the minimum required continuous current rating after applying the 125% factor.
- D. This value is higher than the minimum required rating.
NEC PV AC Output Circuit Continuous Current
The National Electrical Code (NEC) specifies that conductors carrying the AC output from a PV inverter must be rated for a continuous current that is at least 125% of the inverter's maximum output current, ensuring adequate capacity for sustained operation.
- Applies to AC output circuits from inverters.
- Uses a 125% multiplier for continuous loads.
- Ensures conductor can handle prolonged full output without overheating.
Memory trick: Always size the AC wire for PV power, plus a little extra for sure.