Calculate ground fault detection thresholds and fuse sizing for grounded and ungrounded PV systems.
Input Parameters
Results
--
GFP Device Rating
A
--
Max Fault Current
A
--
Detection Threshold
mA or A
--
Potential Arc Energy
J/s
Note: NEC 2020+ allows ungrounded systems with listed equipment. Isolation monitors detect both line-to-ground faults. GFDI fuses replaced by GFPD in current code.
Reference
Grounded: GFP Fuse = max(1A, Isc x 5%)
Ungrounded: Isolation monitor threshold ~30 mA
Max Fault Current = Array Isc
Arc Energy = Fault Current x Voltage x 0.5
Per NEC 690.41 and 690.5