Lamp killing circuit breakers?

[Michael Burr]

Hi all, this situation is so wierd that I'd appreciate some help. I replaced the dimmer module in my torche halogen floor lamp, plugged it in to test, and nothing happened. I then discoverd that all the outlets in my shop area were dead. I went to the breaker box and the circuit breaker didn't look tripped, but I reset it anyway... still nothing on that branch despite multiple resets and unplugging everything.

Still wanting to test the lamp, I went into the garage and plugged the lamp into an outlet that I know was energized because I had just tested it when determining the extent of the shop outlets problem. This time, since I was close to the breaker box, I heard the "click" of a breaker being thrown and still no light from my lamp. Back to the breaker box, where the circuit breaker for the garage outlets looked fine, but once again I reset it anyway... still no power despite multiple resets and removing everything else from the circuit.

Both breakers now appear non-functional after simply plugging in this innoculous halogen lamp! Has anybody seen a case where a simple appliance has "killed" the circuit breakers? I'm really stumped by this...

Thanks,

Michael

[w_tom]

[Steve Smith]

Breakers have to be pushed all the way off and then on again, but it sounds like you've already tried this.

You almost certainly have a dead short in your lamp, in either the wiring or the new module. Is it possible you may have inadvertantly connected the wrong wires?

A short circuit will very often destroy a circuit breaker, especially if they're old. The excessive heat and arcing causes parts inside to burn out. Certain brands are more succeptible to this than others. Age is also a factor. I had a recepticle fall apart and short out at my old home, it ruined the ancient breaker that fed it. At my house now the refrigerator cable got sawed thru while doing some plumbing, the 3mo old SquareD breaker tripped but was not damaged.

New breakers are desgined to handle up to a 10,000A (IIRC) fault and still be usable afterwards, older breakers wern't or may have worn to a point where they can no longer do so. Even though your breaker is a "15amp breaker", in a short-circuit fault situation the actual current will exceed this, by a lot. Since the breaker still has to mechanically open the circuit the current will still flow for a very brief moment while the contacts get moving, all the while the bi-metal inside is still getting hotter. This all may happen in a mere 10th of a second. The net result however is that the conductive parts inside your breaker had enough current flowing through them for that 10th of a second to cause damage.

You should be thankfull the breakers failed safe (ie: won't re-close yet no longer offer protection).

-- Steve

[Patch]

The first thing I'd do is toss the lamp out. Then I'd start looking for a GFI that was tripped.

[PhotoMan]

Good reply Steve! I'll further add that some of the better-stocked hardware stores carry a line of lamp repair kits and parts, including adapters and so forth. It would be good if Michael made a complete job of it, including rewiring the old lamp from the plug to the socket. Joe Arnold

[Michael Burr]

Bingo! Duh... I'd completely spaced the fact that GFI protection on these branches was not with the breaker but by GFI outlets at the head of the branches. Resetting them got me back up... and I do apparently have a nasty short in the lamp to resolve.

Thanks for sanity checking me

Michael

[Michael Burr]

I took that evil lamp completly apart this morning and found a frayed spot on the neutral wire way up in the head part of the lamp. It wasn't all the way thru that I could tell, but it was pressed up against the metal frame of the lame and must have been leaking just enough return current to trip the GFIs.

It's all better now - thanks for the feedback everybody, I really spaced out the GFI outlets when originally considering the problem.

Michael