On Tue, 8 Jan 2008 00:10:18 +0100, the renowned "Steve Lusardi"
wrote:

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

So, it would seem to follow inescapably that the neutrals must be
switched where there are two alternative sources of power, even if
they are isolated from each other, yes?