30 Jan
2011
30 Jan
'11
7:52 p.m.
On Sunday, January 30, 2011, Brian Lanning wrote:
In the US, two separate 110 legs are delivered to the
house. When we
need 220, the magic of constructive interference is applied, and we
get 220. The 220 is delivered to the appliance as two separate 110
wires, a neutral wire, and sometimes a separate ground wire for
safety.
Some things don't have a separate neutral line, in which case they don't
require 120V power.
Because of this arrangement, sometimes appliances (I
believe, maybe
I'm wrong) will pull 110 from one of the legs to power electronics in
the appliance.
Yes, some do that. You can always wire in a 240V to 120V step-down
transformer to run the extra bits. It's rarely much power (timers,
clocks, etc), so you probably could get away with a 100W or so step-down
transformer, which should be pretty cheap.
But I think european 220 doesn't work this way.
Is one 220 leg
delivered to the house? And the electronics work off that 220 leg?
Or are two 110 lines delivered and every outlet gets the sum of those
two 110 lines?
Right, it's ~240V to ground instead of ~120V to ground. As I understand
it, you're a lot more likely to run into 3 phase power (415/240V) than
split-phase single phase power (480/240V), because of how power is
usually distributed.
If it's not two separate legs, I'm thinking
that it will be
impossible to wire an american 220 appliance to work with european
220. Is this right?
No, usually at most you need a small step-down transformer. OTOH, it
may not be legal to connect such an appliance to european power, for
safety reasons, so check your local codes. :)
Pat
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