On Sun, 20 Sep 2009 00:37:22 GMT, (Doug Miller)
wrote:

In article , Darro wrote:
Hi,

I caused a problem with an electrical circuit and would like to know
whether it's a hazard until my electrician has a chance to check
things out.

Scenario:
Two switches (a dimmer switch and a standard toggle switch
--three-way, I think) in two locations control the same two hallway
light fixtures.

As I was pulling the toggle switch out of its metal box, one of its
terminals touched the side of the box and sparked once for a fraction
of a second until contact between the terminal and box was broken.

Why were you doing this on a live circuit?

The switches no longer turn on the light fixtures even though power is
still being delivered to the switches.

How do you know the switches still have power? Did you verify that with a
meter or test lamp?

If I leave the circuit breaker
on (my preference for reasons I won't go into here), would that be a
hazardous thing to do, and if so, why?

I see no evidence that the breaker is on; in fact, you've provided some
persuasive evidence that it's not.

And if anyone has an idea of why the switches no longer turn on the
lights, I'd be very interested in knowing that too.

Probably because you tripped the breaker.

If he got a spark it's pretty obvious he was working on a live
circuit. I do it all the time - carefully of course.
If indeed the breaker is on, and power at the switches, he likely blew
the dimmer switch. They are not particularly robust.

If you want fun, try replacing a main service panel with the system
live!!!!!