|> | Oh just a gloat for you Amaricans! 3phase 230/400 is available most
|> | anywhere except some distant rural properties supplied only with
|> | (Single wire earth return) at some high voltage and a local
|> | to 240 v
|> Yeah, we have wimpy 120/208 for three phase, and even that's not
|> available everywhere. Some places have 277/480. The higher voltage
|> more efficient. That's one of the reasons I try to promote it where I
|> can, for the places and uses where it is safe to do. And our 240 volt
|> circuits are 120 volts relative to ground, so there isn't as much
|> to be concerned over safety as there would be if we adopted 230 volts
|> used in Aus/EU/UK/etc.
|> I'm looking at connecting computers to 240 volts. The power supplies
|> have 2 pole AC switching, so that end is OK (we need that because both
|> wires are "hot" on 240 volts and users of Schuko need it because
|> wire can be "hot"). The catch I've run into is finding a suitable
|> Those wired to handle the "two hots" are generally 5 kVA and up.
| I guess any 240 volt UPS made for Australia should be able to handle
| either wire hot because there is no ABSOLUTE guarantee that the wall
| socket will be wired correctly.
What I have found is that at least many, if not most, UPS systems will
simply gracefully shut down, or at least not accept the input source,
when the voltage configuration is incorrect. I downloaded several of
the online manuals for various European models and found that most had
a means to detect "plug reversal" and indicate the "error" either by
a light or sound. The instructions said to reverse the plug. Some also
said the possibility of the output the UPS is plugged into might be
wired wrong (presumably in the case of places with polarized outlets).
| And I don't imagine there would then be any problem on the US
| (Edison )system where both wires are 120 volts off ground.
It probably would be a significant problem. To begin with, they probably
pass the neutral connection straight through (with the output disconnected
entirely if the plug is reversed).
| I don't want to start the "Mines Safer than yours" argument but there do
| not seem to be many electrocutions here.
I've examined some of the rules in Europe and found that restrictions are
much tighter there. I'd bet they have a lot more experience with higher
voltages than their counterparts in the USA. In the end I bet the final
safety comes out about the same, all things considered. But do consider
the "work site" voltage for outdoor construction work in the UK has been
chosen as 55 volts. Clearly some circumstances have an increased risk of
line to ground electrocution than others.
| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
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