CSLB C-46 Solar ContractorElectrical and Plumbing CodesMedium
A solar contractor is calculating the maximum current for PV source circuits within a PV array. The PV modules have a short-circuit current (Isc) of 9.2 A. The array will be installed in an area with an ambient temperature that can reach 40°C. According to NEC Article 690.8(A)(1), what is the maximum circuit current (Imc) for these PV source circuits, before applying any continuous load multipliers?
- A11.5 A
- B12.0 A
- C9.2 A
- D10.12 A
Show answer & explanationAnswer & explanation
Correct answer: A. 11.5 A
NEC Article 690.8(A)(1) requires that the maximum circuit current for PV source circuits be calculated by multiplying the short-circuit current (Isc) by 125%. Therefore, 9.2 A * 1.25 = 11.5 A. This factor accounts for potential increases in current under certain operating conditions.
Why the other options are wrong
- B. This value does not result from the correct NEC calculation for Imc.
- C. This is the Isc, not the maximum circuit current (Imc) as required by NEC 690.8(A)(1).
- D. This would be an 110% multiplier, which is incorrect for PV source circuits.
PV Source Circuit Max Current (Imc)
The maximum circuit current for PV source circuits is calculated by multiplying the module's short-circuit current (Isc) by 125%, as per NEC 690.8(A)(1).
- Accounts for potential overcurrent conditions.
- Used before applying continuous load factors for OCPD sizing.
- Ensures conductors and components are adequately rated.
Memory trick: PV Max Current: Isc Plus a Quarter More.