Yeah, I was thinking about that too.. If you're
drawing enough current to
blow a 100A breaker through a system power cord (18 - 14AWG here in the
states), you'd end up with a very melty power cable.
In the UK, the standard mains plug contains a cartridge fuse in series
with the live wire (it's a 3 pin plug, polarised, so live and neutral
can't be swapped by plugginhg it in upside-down or anything). The
standard ratings for these fuses are 3A, 5A and 12A (others do exist). I
would expect most micros would be happy with a 3A plug fuse (that's over
700VA , after all).
Now, if you have several protective devices (fuses, circuit breakers) in
series, it's not always the case that the lowest-rated one blows in the
event of a fault, but in general the characteristics of the MCBs used in
house wiring are such that the plug fuse _will_ blow first in the event
of a fault in the device. The MCB is there to protect against faults in
the fixed wiring.
In this case, I would be suprised if that '100A breaker' was not a
100A-rated RCD, and that it doesn't trip on overcurrent anyway. I've
never seen a domestic wiring installation where the main switch was
anything other than either a plain on/off switch or an RCd.
I think it's gotta be a ground-fault that's causing Witchy's problems.
I am almost sure it is.
-tony