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-   -   Circuit out but circuit breaker didn't trip (http://www.diychatroom.com/f18/circuit-out-but-circuit-breaker-didnt-trip-24841/)

PaulenAndrew 08-06-2008 09:46 PM

Circuit out but circuit breaker didn't trip
 
I replaced a light fixture in the basement (just a stuck pull cord) by turning off the main switch in the circuit breaker box, replacing the fixture and turning on the main switch.

Most of the electricity came back on as expected but, ever since, I have a lights circuit that is out. It can't be bulbs because there is also a nearby fan that is suddenly off. It can't be that the circuit breaker broke it because it was never tripped and it was on a different circuit than I was messing with and had no issue with anyway. I read that if a circuit breaker was defective it would be tripped all the time. It never tripped! And why would it break now!

So I just tried flipping everything on and off (not even sure which it is because the labelling is terrible) and it's not making any difference. Nothing *looks* loose.

Is there something obvious I should be checking before I call an electrician? I have a feeling he or she is going to come in here, flip a switch and laugh at me.

Thanks,

Paul

TazinCR 08-06-2008 10:27 PM

Buy a cheap voltage tester. One with a light is fine. Check the lug on the CB and see if it has power. This is where you start.

fw2007 08-06-2008 11:37 PM

Sure sounds like something loose in the panel. Maybe when you tripped the main, then turned it back on, that was enough of a vibration to open the bad connection.
The breaker itself may not be defective, or even loose on the bus, but the wire connecting to the load side of the breaker may be loose. I would check all of the breakers that way.
Definitely a good idea to shut off the main while doing this, just in case your screwdrive slips. And of course never touch the terminals of the feed side of the main unless you are using an insulated / non-conductive screwdriver!!

FW

petey_c 08-07-2008 01:39 AM

PaulenAndrew, It was good that you reset all the CBs. Often times, people will rely on the breaker "looking" tripped, ie. the handle in the tripped (halfway) position or even with breakers that have indicators (Pushmatic or Square D) and assume that the breaker is working fine. An inexpensive tester is always good to have. Make sure that the tester leads are long enough to comfortably reach from the breaker you're testing to the neutral bar(s) with out stretching too much.
Sometimes the neutral or hot can slowly work loose over time, if it wasn't torqued enough to start with. fw2007 has a good idea - tighten all the neutral/hot screws after making sure the main is off. Having 2 people to do this is also a good idea, so you don't wind up with a stiff neck from holding the flashlight with your shoulder. (Many stores (Wal-M, K-M, Home De, etc) sell LED flashlights that you can wear on your head which gives you more mobility.) Stay away from where the mains connect to the breaker, even with the main breaker off, these wires are still hot.
How many wires were in the box where you replaced the pull chain? If there were only 2 (black and white) no problem. If there were other splices going on, you might have accidentally knocked something loose (wires not twisted together under a wire nut, or a broken wire caused by someone getting a little too enthusiastic with wire strippers. The wire breaks just where the insulation ends, but looks like it's still good). Hope this helps, pete

fw2007 08-07-2008 10:08 AM

Petey_c; Good point on the number of wires in the box.I have seen wiring where two separate circuits use the same box. Not code of course, and very dangerous to anyone who is working on the box!

For light, I use a Petzl climber's headlamp. It's not LED but crypton. A real nice light, which I bought for hiking, but comes in handy for lots of other stuff.
The headlamp is a must when working alone.

FW

Stubbie 08-07-2008 11:01 AM

Unfinished basements receptacles must be gfci protected. If that lighting and fan circuit is getting its power from a connection to a gfci receptacle the gfci may be tripped out. Look for a gfci and see if it has tripped, simply reset it and your lights will magically return. In almost all cases when you lose a circuit after recent work is completed it is related to something that occurred during that work....:thumbsup: The common point since the lights are not on the circuit you worked on was the main breaker you turned off. When you turned this main back on you very likely had a gfci trip out in the basement... and the fact that a fan may be involved brings me to believe it is the cause for the gfci tripping.

I hope you have not chased a problem in the inside of the panel until you look for a gfci first. Checking the breakers was good...

they look like this

http://tbn0.google.com/images?q=tbn:...2494619303.jpghttp://tbn0.google.com/images?q=tbn:...ages/4540w.jpg

Stubbie 08-07-2008 11:22 AM

Quote:

Good point on the number of wires in the box.I have seen wiring where two separate circuits use the same box. Not code of course, and very dangerous to anyone who is working on the box!
It is not a code violation to have different circuits in the same electrical box. Is there a place where you are seeing this written in the code book??

J. V. 08-07-2008 11:37 AM

I'm with Stubbie. If it's not a GFCI receptacle, open the box where you changed the light. Best bet is there is a loose wire or incorrectly connected wires that feed the other circuit. This is very common.

Yoyizit 08-07-2008 12:43 PM

I diagnosed a bad breaker.
The counterguy confirmed it.
The customer had her checkbook out and was writing a check for $38.

Then the counterguy said, "Watch this."

He whacked the breaker handle back and forth as hard as he could a few times.
Lo and Behold, continuity, and it still works (this was years ago).

If you try this, first turn off everything downstream of the breaker.

Stubbie 08-07-2008 12:57 PM

Quote:

I diagnosed a bad breaker.
The counterguy confirmed it.
The customer had her checkbook out and was writing a check for $38.

Then the counterguy said, "Watch this."

He whacked the breaker handle back and forth as hard as he could a few times.
Lo and Behold, continuity, and it still works (this was years ago).

If you try this, first turn off everything downstream of the breaker.

This is a joke..... right?.....:yes:

http://www.diychatroom.com/images/st...ser_online.gif http://www.diychatroom.com/images/buttons/report.gif http://www.diychatroom.com/images/buttons/quote.gif

fw2007 08-07-2008 01:10 PM

Quote:

Originally Posted by Stubbie (Post 146698)
It is not a code violation to have different circuits in the same electrical box. Is there a place where you are seeing this written in the code book??

No, but my better judgment says don't do it. I would only assume that code would prohibit it. Don't you think it's dangerous to someone working on the box?
The only way to be completely safe in such a situation would be to shut off the main.
Should this be necessary for working on branch circuits?

If the person who installs such a configuration were to label the box with the breaker numbers that feed it, all would be resolved, but I rarely find this to be the case.

FW

Stubbie 08-07-2008 01:42 PM

There certainly is nothing wrong with thinking that way. It would be safer in the sense that if an unknowledgeable person accessed the electrical box he may overlook the fact that power is still on a circuit other than the one he is going to work on.
However we wire according to the equipment, devices, appliances that will be supplied or controlled from that box . This commonly requires multiple circuits in one electrical box. Multiwires are just as likely to fool an unknowledgeable person as individual serparate circuits in the same box.. In recognition of that fact code has been changed to require double pole common trip breakers for multiwires. It is not practical to wire a home or business to be idiot proof if I can use the term without insulting anyone. Electrical systems are inherently dangerous thats why we keep them inside walls and boxes and not easily touched by the unexperienced. Anyone getting into a electrical box needs to have enough common sense to check for voltage whether an electrician or not.

Which is why we have DIY forums so we can make sure these people who come here are safe as possible cause they are going to get in that box with or without our help.

As a side note when I see how many electricians or handymen have mishaps inside panelboards/ loadcenters in residences I sometimes think we should never advise inexperienced homeowners to venture there....:)

Yoyizit 08-07-2008 01:52 PM

Don't know how to work the embedded quote thing.

No joke.
Possibly there was grime on the contacts which were wiped clean by the repeated closings?
I never checked the millivolt drop across the closed contacts of this breaker before or after, but it has worked now, for years.

Dunno'.

fw2007 08-07-2008 04:16 PM

Stubbie;
When I talked about multiple circuits in one box, I was thinking of junction boxes, not outlet boxes, just to clear up my point a bit.
I recently wired two duplexes in a double-gang box, each duplex is on it's own 20A dedicated line.
When you talk about multiwire, I hope this doesn't refer to two completely separate cables coming into the outlet box. If it does, then I have to replace the two 20A breakers with a double pole breaker. I would rather not have to, and didn't think I needed to because i used separate cables instead of a 3-wire cable.
Either way, I won't worry about it until I have an inspector come and tell me I have to change it<g>.

FW

Stubbie 08-08-2008 01:06 AM

Your fine with what you have. A box is a box in my book whether JB or otherwise. I do understand what your saying, it just isn't always
possible to keep circuits separate...anyway this was good discussion and I hope you weren't offended by anything I said in regards to your comment earlier. I'm simply saying the NEC does allow different circuits in electrical boxes of all types.


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