23 Mar
2004
23 Mar
'04
10:02 a.m.
If you break both, the device could float. Floating
parts
are generally not good in the electrical world, as their behavior is
Exactly why not?
Are you saying that the main switch in your fuse box / consumer unit /
breaker box / whatever you call the thing after the electricity meter in
your house is a single pole device ? In the UK it is _required_ to be a
double pole one, breaking live and neutral (and for 3 phase star
installations it's required to break all 3 phases and neutral).
uncertain. It is always better to have a circuit whose
behavior is known -
even if the behavior involves fuses blowing for even silly little faults -
The behaviour of a circuit with a double pole mains switch is known. And
I have _never_ come across a problem that could only be explained by the
fact that both mains wires were disconnected.
than to have one that could go anywhere.
Floating circuits are also no fun for electricians. Many have been fooled
(and zapped) when their wiggie lit (or did not light) because one end was
connected to a flaoting wire.
The most common problem is that your neon tester will light on a
disconnected wire due to capacitive coupling to a still live wire. This
is a safe error, in that it says a wire is live when it's not. For the
life of me I don't see how a totally isolated circuit can test dead on a
neon tester but actually be live (in fact I don't see how it can be live
at all if it's isolated on both live and neutral wires).
Wiggie: A small neon bulb tester, used by electricians to do quick and
dirty checks for voltage.
Horrible things!.
-tony