Electrical Engineering - Re: Yet Another 120 vs 240 (was: Why has Romex wire gotten so expensive?)

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Re: Yet Another 120 vs 240 (was: Why has Romex wire gotten so expensive?)

Michael Moroney

2006-06-25, 1:25 pm

What I would do:

Everything would be made to operate from 240V.

The 240V would be supplied from center tapped transformers, with the
center tap grounded. In other words, the current American system.
The center tap would be used for nothing but grounding. No 120V devices.

3 phase would be 240Y/139, with the Y center point grounded. Again,
everything uses 240V either single phase or 3 phase, nothing gets
connected to the center point except the ground.

This gives the best of both worlds. Devices draw less current thus more
safety there. Touching any hot by a grounded person will only give you
a 120V shock, unless touching 3 phase where you would get zapped with 139V.
You'd need to manage to touch 2 hots at once to get zapped with 240V.
GFCIs could be used everywhere. No 4 wire 240V circuits, 2 hots+ground
everywhere. 3 phase has 3 hots+ground.

The big drawback is all light switches need to be double pole, and 3 way
switch circuits get "interesting".

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