On 06/06/2019 22:42, Dave Liquorice wrote:
On Thu, 6 Jun 2019 19:51:22 +0100, Nightjar wrote:

The USA has a +55v 0v -55v system.

You sure about that? I thought US domestic supplies where 110 V
biphase. ie 110 - 0 - 110. Normal appliances where connected between
0 and one of the phases. Big loads like washers connected between the
phases and ran off 220 V and thus half the current for the same power
@ 110 V.

Old age catching up with me. I realised I had got that wrong shortly
after I pressed the send button. Those are the voltages for inherently
safe systems. However, the principle remains the same that black and red
are both colours for live wires, with white for neutral.

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Colin Bignell