I dug up a copy of
UL458 and spent too long looking at it. I didn't find much at all about GN bonding.
I did find this part:
30.1.3.1 The grounding connection and the output neutral of an inverter that is intended to be connected
to the cigarette lighter outlet of a vehicle shall be bonded to the inverter frame or enclosure.
Which seems to require GN bonding, but only for inverters intended to be attached via cigarette lighter (there are a bunch of relaxations earlier in the document for inverters of this type, so this is probably added to claw back some of the safety given up earlier).
Perhaps this document is old, or perhaps I should be looking at the "marine supplement" or maybe I just missed it.
When I power up the inverter I'll check the voltages.
