>On Sat, 16 Aug 2008 08:23:26 GMT, Richard Sherratt
>NOTHINGHEREbrunsley.com.au> wrote:
>

>>There's some complicated maths involved and it's nearly 40 years since
>>I studied it, so my head is dead. We're dealing with ac current, so
>>that means we need to understand sine waves. [1] That means that the
>>voltage is affected by the angle. Clear as mud, right :-)
>>
>>Three phase voltage in a 230-240 volt system is actually around 400
>>volts. One of the times we lived in Germany (Bielefed, I think), the
>>oven had a three-phase 400 volt supply. Thre square root of 3 is
>>involved.

>
>Yes. I remember, in Germany, that the water heater above the sink in
>my shower room had a three-phase conection. I asked an electrician if
>it was safe and he said yes of course but don't mess with it. It
>didn't look safe to me. I was under the impression that it was about
>450 volts rather than 400, but it was all a long time ago and my
>memory might be faulty. I also remember being told that if there is a
>short circuit between phases, the voltages involved can be huge and
>all sorts of weird things start to happen. You know, Bad Things, as in
>Ghostbusters when the lines cross.