Paul has raised a pertinent issue. I find it hard to believe that the power
distribution in Thailand or any other country is completely floating with
respect to ground. Were that the case, then the entire concept of a
"neutral" would have no meaning. In HV power supplies which have a B+ and a
neutral current return, one always anchors the neutral line with a resistor
(100 ohms typical) to chassis ground. This is done to keep the B+ from
soaring uncontrollably. The same reasoning applies to an AC power
distribution system.
73,
Jim W8ZR
> -----Excerpt from Original Message-----
> > > about 80% of Thailand buildings have TWO holes in the 220VAC wall
sockets
> > and ONLY TWO HOLES. One side is definitely hot and the other side is
> > definitely neutral. The pin sockets, the holes, are not marked and not
> > keyed in any way. There is NO GROUND present by any means...no wire
> > ground, no BX cable nor conduit.
>
> 1) Is the receptacle keyed in any way to ensure proper hot and neutral
with
> mating plug connections?;
> 2) Is the neutral absolutely floating above all grounded and grounding
> conductors (e.g, a water pipe or water-fed room radiator)? That of course
> assumes piping is even grounded in Thailand. Or, is neutral simply a
> floating return for the hot (which in reality would make it another hot
> conductor). Even though the receptacle has no ground reference, is
neutral
> grounded/earthed at the service entrance or at some point upstream from
the
> utility provider?
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