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Figure 4-4 Grounding of the Inverter and Integrated AC/DC Disconnect
Ground Fault Interruption Circuit (GFI)
The purpose of the GFI circuit is to detect a ground fault current, interrupt
the flow of a fault current and provide an indication of the fault.
A ground fault is defined as “unintended current flow to ground” which
presents a hazardous condition.
• For the GFI circuit to function as designed, the GEC must be con-
nected only at the ground terminals detailed in Figure 4-6.
• Bonding the GEC to the grounded leg of the array anywhere but
through the inverter bypasses the GFI circuit.
• The GFI circuit operates by bonding the PV array negative or posi-
tive to earth ground through a 600 VDC 1-amp fuse. The GFI circuit
activates if any DC ground fault currents are greater than 1 amp. The
GFI circuit opens the 1-amp fuse, interrupting the fault’s current path,
disabling the inverter’s power production and displaying a unique error
• The GFI is a latching circuit which prevents the inverter from operat-
ing until the fault is repaired and the inverter is reset. The inverter
will not operate, even if the fault is repaired, unless manually reset by
turning the AC source circuit off and then on.
Inverter Cabinet
Disconnect
Cabinet
Disconnect
Grounding Lug
Inverter
Grounding Lug
PV GFI
GEC Conductor
EGC Conductor
AC Ground
Terminal
