When a ground fault occurs, the inverter will shut down
within seconds. Most inverters contain a GFDI fuse that trips
when any ground-fault current exceeds the ampere rating of
the fuse. For residential grid-direct string inverters, this is
a 1 A midget style fuse, typically a type KLKD or equivalent.
However, due to the higher levels of leakage currents found
in large arrays, central inverters usually have GFDI fuses
with higher trip ratings: 2 A, 3 A, 4 A, 5 A and even higher
values are typical. In some cases, for ground-fault protection
central inverters utilize a resettable circuit breaker or a current
transformer inside the inverter with an adjustable trip
value. Several central inverters also have early warning circuitry.
This circuitry monitors any current on the ground bus
or grounding jumper and may shut down the inverter before
the actual GFDI fuse has blown