Jim Lux wrote:
>> The power company also grounds the
>>neutral connection at the transformer to earth ground.
>Not necessarily.. for the same reason as you have a single interconnect
>between neutral and ground. You don't want neutral return currents
>flowing back to the transformer via the ground path.
>Also, if the neutral opens between your house and the transformer
>(which does happen, particularly on an overhead service), you don't
>want the entire neutral return current flowing through ground. You'd
>rather have the voltages on the two sides become unbalanced. Radical
>voltage fluctations may destroy equipment, but at least it doesn't
>create a shock safety hazard.
Interesting... the power companies in the UK take a different view. In
the event of a neutral break in their local distribution system (230V
single-phase, neutral close to earth potential) they'd rather have the
return current flowing back through earth than create a shock hazard due
to the neutral becoming hot.
Therefore they almost always earth the neutral at the transformer,
and/or anyplace else they conveniently can. Having made that policy
decision a long time back, they have created the expectation that
neutral will be safe to touch when doing household wiring work, so now
they're perpetually locked into that policy.
73 from Ian G/GM3SEK
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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