Electrical circuit hazard?

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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.
The switches no longer turn on the light fixtures even though power is still being delivered to the switches. 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?
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.
Thanks in advance for your replies, Darro
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Why were you doing this on a live circuit?

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

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

Probably because you tripped the breaker.
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On Sun, 20 Sep 2009 00:37:22 GMT, snipped-for-privacy@milmac.com (Doug Miller) wrote:

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!!!!!
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Darro wrote:

It's because they are broken. Buy new ones, and they should work.
Jon
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wrote:

Manually throw the breaker to the off position, then on, then off, then on again and see what happens. If no light, you may have fried the dimmer switch.
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hr(bob) snipped-for-privacy@att.net wrote:

This would be my answer too.
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wrote:

Regarding this thread am sure the advice is good and well intentioned. But IMO don't think the OP is sufficiently knowledgeable to absorb it and/or act upon it; safely. Starting with moving one of the switches on a live circuit, without first checking and shutting off at least the circuit breaker for 'that' circuit. When it comes to shutting off 'all' power in, say, a house. Not necessarily essential but may be appropriate if there is a lot of doubt or confusion and/or if the original wiring/ circuitry has been messed about with, modified and/or obviuosly non standard circuits have been added.
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On Mon, 21 Sep 2009 08:31:48 -0700 (PDT), stan

I've been changing switches on live circuits for something better than 40 years - not a shock yet, and only burned off one screw driver, about 40 years back.
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Most new dimmers are electronic (using a triac). Not very forgiving to shorts...or as Jon said in a nutshell, iz broke.
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donmorgan had written this in response to http://www.thestuccocompany.com/maintenance/Electrical-circuit-hazard-395627-.htm : Working on a live circuit can be dangerous. If you do indeed have power to the switches and can confirm this the problem could be that the switches are electronic and not mechanical. They probably are electronic if they are dimmers. Meaning that they use transistors or integrated circuits to function. If you caused a surge by shorting them out you could have damaged the circuitry. The only one affected should be the one that was surged. In a three way configuration the switches work together to pass the power between each other and on to the light. If one goes bad this can stop the flow back and forth between the switches and the light fixture.
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more info at: http://www.faqs.org/faqs/electrical-wiring/part1 /
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ALWAYS turn off the main power to the house before doing electrical work!
I suggest you call an electrician.
"Darro" wrote in message

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Complete and utter nonsense.
Turning off the branch circuit you're working on is quite sufficient to ensure safety.
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On Sun, 20 Sep 2009 05:31:53 -0700, "Bill"

Tuyrn off the MAIN power????? NO way. Just throw the breaker on the circuit you are working on - or keep one hand in your pocket if you have an idea what you are doing.
If you don't have a good idea what you are doing, call in a "sparky"

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Bill wrote:

If you know how current flows you can avoid it flowing through you. If you are a complete idiot, shut off the breaker.
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wrote:

And if you have a sudden need for the bathroom halfway through, and wife/child/pet comes in to see the pretty wires while you're gone???
There are times when you have no choice but to work live. When you have a choice, usually better to be 100% safe than 95%.
That's at home. At work it's a different story. OSHA applies, and most of the time you are forbidden to work live. Zero Energy State, Lockout Tagout, etc.
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wrote:

You put a wire nut on the end if you need to leave a wire live.
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On Sep 21, 1:28pm, snipped-for-privacy@snyder.on.ca wrote:

I don't mean to offend you personally, but I'll point out something.
I've seen a lot of maintenance workers and mechanics over the years in industrial settings.
Without exception - without exception! the ones who were sloppy about killing the circuit power or other safety habits were also sloppy about doing a good job. It was like carrying a sign - "check my work, twice, 'cause it's not gonna be right the first time."
I know that's kind of biased. And you may do perfectly competent craftsmanlike work yourself. But just as a warning, if I know you work live when the circuit breaker is a few feet away, I and most of my peers have concluded you're going to do a half-arsed job, and we're not going to hire you.
It's not easy to figure out who WILL do good work. But there are some clues as to who will NOT, and this is one of them. Sorry if it targets you unfairly.
Of course in your own home, how you do your DIY is up to you.
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wrote:

When the breaker is 3 floors down at the other end of the building and the only light to work by is on the same circuit, it is safer to keep that light on and work live than to shut the power off and try to work holding a flashlight. Generally on 220 volt and dedicated power circuits I DO shut off the power.
However, when the main breaker on the cottage panel blew, friday of a wintery long weekend, we just grabbed a new panel and breakers before the stores closed, and changed the panel without pulling the meter.Wives holding the flashlights, tape up the ends of the wires pulled from the main breaker, strip out all the branch circuit wires, yank the panel, feed the taped wires onto the top of the new panel, connect to the main breaker, connect the circuit that lights the basement, and shut off the flashlights. Then finish the wiring (get the heat on PRONTO!!!,) then the rest of the cottage.
Generally with light switches I'm troubleshooting live (really no other way to do it, particularly with 3 ways)) and when I find a bad switch I just pull it and replace it.
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snipped-for-privacy@snyder.on.ca wrote:

I'd have called the power company and told them I was cutting the seal due to an emergency. If they want to send a representative out to check, we'll be in the back yard laboring in the cold and the dark and the wet.
What you did is not all that unusual. After all, what do contractors do when they install a new meter box and have to work with the drops?
They use caution, that's what they do.
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