The code is simple. Neutral is tied to safety earth at only one location or
ground loops are formed and by convention this is at the source of power.
Another rule is that safety earth should never be switched. So, a source of
power is a distribution transformer or a generator (read inverter) All other
electrical connections are consumers. Consumers use distributer connections
for phase, neutral and safety earth. Consumers are not allowed to create
their own earth.

In the case of multiple sources and a common load, there can only be one
earth reference and neutral of each source is connected to that singular
earth reference at each energy source. Ideally, all sources should be as
close as possible to the earth reference.
Steve


"Spehro Pefhany" wrote in message
...
Hi, guys,

Question for those knowlegable about electrician and code type stuff..

I have a situation where there we are wiring what is, in effect, a
transfer switch which will connect external 120VAC/60Hz power to two
sets of loads (sort of like the 240VAC/center tapped situation in a
home) OR a pair of 2kW inverters.

When external power is supplied by a line cord, the neutral and ground
are effectively tied together, however once the line cord is
disconnected the ground (chassis etc.) and the inverter neutrals are
tied to each other, but floating with respect to the ground.

Are there safety or "code" (not sure any code really applies to this
situation when it's unplugged and far away from any power lines)
issues with letting neutral and ground float wrt each other in an
inverter power situation from an electrical wiring point of view?



Best regards,
Spehro Pefhany
--
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