I have rigged a 1000watt/120vac inverter to my EV, to use for backup electrical power during short grid outages (the main "traction" battery has 40kwh and the DC-to-DC converter is known to be able to supply 135 amps to the 12v system). The inverter has duplex GFCI outlets.
I could just run extension cords to the few loads I'd like to support (fridge, modem, a few lights), but I'd prefer to feed the main panel (using an interlock, of course). I'll probably just feed one phase of the panel, and shuffle a couple of breakers if necessary to get the loads I want (though feeding both phases from the 120vac may be possible, see: feeding both sides of load center from 120vac backup source).
The problem is, ground and neutral are (of course) bonded in the main panel. This will cause the inverter's GFCI outlet to trip - GFCI's typically test for a ground-neutral short (as well as, of course, an imbalance in the hot and neutral currents).
Question: would it be inadvisable to simply connect the GFCI's hot and neutral to the main panel (via an interlocked breaker) and leave the ground disconnected ? Seems the house would still have a working ground network, and hazards from the inverter are protected by GFCI; the only real hazard would be if the inverter's case became energized.
P.S. Yes, I realize there are other, more complicated, approaches. A critical-loads sub-panel, which would have to be connected to the main via a breaker that also disconnects neutral. Or separating the ground and neutral connections onto separate busbars in the main panel, with a ready means of temporarily de-bonding them.