CSLB C-46 Solar ContractorPlanning and EstimatingHard
When performing system design for a residential PV installation, the National Electrical Code (NEC) article 690.7 requires that maximum system voltage (Vmp) for a PV array does not exceed a certain limit for one- and two-family dwellings. What is this maximum DC voltage limit?
- A1500 V
- B300 V
- C1000 V
- D600 V
Show answer & explanationAnswer & explanation
Correct answer: D. 600 V
For one- and two-family dwellings, NEC 690.7(C) specifies that the maximum PV system voltage shall not exceed 600 V DC. This is a critical safety limit for residential applications.
Why the other options are wrong
- A. This voltage is generally reserved for very large utility-scale PV systems, exceeding common commercial or residential limits.
- B. This is a common voltage for small-scale battery systems, not typical for grid-tied residential PV array maximum voltage.
- C. This is the typical maximum system voltage for commercial and utility-scale PV systems (NEC 690.7(A)).
NEC Residential PV Voltage Limit
The maximum DC voltage permitted for PV systems installed on one- and two-family dwellings, as specified by the National Electrical Code.
- Ensures safety for residential occupants and first responders.
- Defined in NEC Article 690.7(C).
- Differentiates from commercial/utility limits.
Memory trick: Residential is 600, commercial to 1000, safety's the rule, no need to groove!