On Tue, 08 Jan 2008 17:04:05 -0500, Spehro Pefhany
wrote:

On Tue, 08 Jan 2008 16:08:56 -0500, Ned Simmons
wrote:


I don't have a clear enough picture of your equipment in all its
possible configurations to tell whether the NEC would consider it a
separately derived system. Is it portable? Is there an earth ground
other than thru the line cord?

Not really. It's in a moving vehicle.

The NEC does have a section on RVs, which even if not directly
applicable, may give some guidance.

Based on my understanding of the situation, I'd create a neutral by
bonding the common connection between the inverters to the vehicle's
chassis, and switch the neutral along with the hots when selecting
inverter or utility power.

I might reconsider if the inverter batteries can be charged by utility
power, and there isn't isolation somewhere between the utility input
to the charger and the inverters' outputs.

--
Ned Simmons