CSLB C-46 Solar ContractorElectrical and Plumbing CodesMedium
A solar contractor is troubleshooting a ground-fault within a PV array's DC wiring. According to NEC Article 690.5, what is the primary function of a ground-fault detection and interruption (GFDI) device in a PV system?
- ATo optimize the power output of the PV array.
- BTo prevent overcurrents from damaging PV modules.
- CTo monitor the voltage and current levels of individual PV strings.
- DTo detect and interrupt ground-fault currents to reduce fire and shock hazards.
Show answer & explanationAnswer & explanation
Correct answer: D. To detect and interrupt ground-fault currents to reduce fire and shock hazards.
NEC Article 690.5 explicitly states that PV systems shall be provided with a ground-fault detection and interruption (GFDI) device. The primary function of this device is to detect ground-fault currents and quickly interrupt the circuit, thereby reducing the risk of fire and electric shock hazards associated with such faults.
Why the other options are wrong
- A. Power optimization is typically handled by Maximum Power Point Tracking (MPPT) inverters, not GFDI devices.
- B. Overcurrent protection is handled by fuses or circuit breakers, not primarily by a GFDI device.
- C. Monitoring is done by system controllers or inverters, not the GFDI device, which is a safety interruption device.
GFDI Device Function (PV)
A safety device required by NEC 690.5 in PV systems to detect ground-fault currents and rapidly de-energize the affected circuit, mitigating fire and shock hazards.
- Required in PV systems by NEC 690.5.
- Detects ground-fault currents.
- Interrupts the circuit to prevent fire and shock.
Memory trick: GFDI: ground faults it will find, and dangers it will bind!