Xantrex Inverter Grounding

[TheAussies]

It seems there is some confusion regarding the correct way to ground the chassis of an inverter. Our previous inverter chassis was grounded with a bare copper wire, about 8 AWG, only. The Xantrex grounding instructions for our newly installed 3kw inverter are confusing regarding AC grounding/bonding grounding/DC grounding. Those instructions appear to suggest a very heavy chassis grounding wire going back to the battery negative buss (perhaps 3/0 or 4/0). In our case the inverter is fed with 4/0 positive and negative wires, with a 350 amp fuse in the positive wire. How are others handling this problem please ?

[elnav]

The instructions by Xantrex is to conform to ABYC standards. RV spec does allow a #8 ga wire but not ABYC.
Their rationale is to give a large ampacity path in the event a wire inside the metal chassis got loose and grounded.
They want to be able to blow the large fuse in the supply line if a fault exist. Refer to ABYC section 31 Para 6.3
We lost the argument concerning very large cables being sized to prevent voltage drop and allowing the chassis cable to be based on the actual fuse size. I worked for Xantrex at the time and attended the ABYC meetings.

So the specifications require a fuse at the supply end and a chassis ground of equal size as the supply cable. But wait! The inverter also serves as a charger. Guess what? ABYC standards even provides a diagram showing a fuse at the charger end as well as the batery end. refer to ABYC section 31 Figures 3 and 4 and described in paragraph 5.2.6
This is to conform to the 72" rule. ABYC requires over current protection be placed within 72" of the power supply end or 7" if fed directly from a battery terminal.
Ignore this at your peril because insurance surveyors are getting increasingly tough on electrical systems meeting spec.