Tricks for finding wiring problems that tripped a breaker?

[Citation]

Yay old houses...

So this morning I heard a buzzing noise and the lights seemed to dim. I'm not sure what triggered this but I've verified that one of my old push button breakers (Pushmatic?) has tripped. Resetting it results in a buzz from the breaker itself. Note that I was on the second floor when this happened and the breakers are in the basement so I assume I heard buzzing in the wiring caused by... something?

I believe this breaker provides power to ceiling lights in a hall and two bedrooms as well as the outlets in those bedrooms. I know some of those lights use old metal clad cloth insulated wire. I also assume (without proof) that most of that stuff has never been moved since installed except where it goes into ceiling fixtures.

Any easy way/tricks to telling where the problem might be?

 

[kd3pc]

could be a bad breaker...replace or swap panel space with one that works - would be my first move....second would be to turn the breaker off, remove the feed wire from it and ohm out that homerun, end of wire to panel ground and neutral - BE careful in the panel and if you are not comfortable doing this, for sure hire an electrician. Then similarly ohm out the neutral (to wire end and panel ground).

 

[Terry D]

So when you say the lights dimmed and then said the breaker tripped, Im assuming after the trip that the lights were off completely. Try hooking it up to a different breaker in the panel. Probably not the problem but worth a try. A short can cause a buzzing noise until the breaker trips. There is no quick way to find the short. First determine what is on the faulty circuit. If there are receptacles, unplug everything from them. If this is a old house, you possibly don't have and grounds. Turn all light switches off. try to reset the breaker, if it starts humming, turn it back off. If it holds, its in one of the lights. If not, you have to start opening up switch boxes. receptacle boxes and ceiling boxes. Possibly J-boxes in the basement. If the wires are old and brittle, that makes trouble shooting it even worst. You can create more problems. Look at all the ends of the BX cable to make sure the anti short bushings are in there. If you open up the circuit half way from the beginning to the end. It could tell you what half it is in.

I should of mentioned this first, if you don't feel comfortable doing this, please hire a pro. I personally would not try to reset the breaker each time to see if the short is cleared. I would remove the wire from the breaker and use a meter. Read from a hot lug to the wire you removed from the breaker, you will read 120 volts if you have a short present. With all the light switches off and everything unplugged, you should read zero when the short is cleared. Unless of course you have a house that they ran the neutrals to the switches, then you will read voltage, but will be lower than 120 volts

If you have any Fluorescent lights in the circuit, it could be a bad ballast

 

[unslow1]

When I've had that happen it was the breaker that was bad.

 

[nadogail]

Without feedback from the OP; I see no point in further comment.

 

[cmandp]

Without feedback from the OP; I see no point in further comment.

I think it might be reasonable to assume that the op has figured out it was safe with the breaker off for now and has probably gone to work. That's what I'd do if I woke up to the same problem.

 

[Citation]

Thanks for the replies all. This happened this morning before I headed to work so I haven't had much time to look into things.

Yes, I'm comfortable working around home wiring.

Based on comments above I think my first plan will be to pull the breaker and use a meter to check for an obvious short and see if I can isolate it to a light circuit or wall outlet. Like many old houses with upgraded wiring this place has a mix of wiring types. If I don't find anything I'll put the suspect breaker into a known good circuit and try it.

I think several (all?) of the ceiling lights on this circuit still use original 1935 wiring. If the problem is inside a junction in the wall is there any trick way to isolate it? While I can get to fixtures and outlets I have no idea where/how things were done in the walls and I don't want to punch holes in plaster to guess and check.

 

[Citation]

I think it might be reasonable to assume that the op has figured out it was safe with the breaker off for now and has probably gone to work. That's what I'd do if I woke up to the same problem.

Yes, I left the breaker off and had to head to work.

 

[cmandp]

Thanks for the replies all. This happened this morning before I headed to work so I haven't had much time to look into things.

Yes, I'm comfortable working around home wiring.

Based on comments above I think my first plan will be to pull the breaker and use a meter to check for an obvious short and see if I can isolate it to a light circuit or wall outlet. Like many old houses with upgraded wiring this place has a mix of wiring types. If I don't find anything I'll put the suspect breaker into a known good circuit and try it.

I think several (all?) of the ceiling lights on this circuit still use original 1935 wiring. If the problem is inside a junction in the wall is there any trick way to isolate it? While I can get to fixtures and outlets I have no idea where/how things were done in the walls and I don't want to punch holes in plaster to guess and check.

Well if you find you have a junction hidden in the wall (box or not) I would abandon it at all costs. I'd be trying to fish a new wire to the fixture by all means possible. I say this from having finding many hidden junction boxes in walls in our house. We found it fairly easy to fish wires in our house (built 1871) as there were many spaces to run wire. But we had walls open walls and a ceiling that needed to be redone so we cut access in it.

I can't help you anymore than the others with trouble shooting, they have already given good advice above my level of experience.

 

[Terry D]

If

Thanks for the replies all. This happened this morning before I headed to work so I haven't had much time to look into things.

Yes, I'm comfortable working around home wiring.

Based on comments above I think my first plan will be to pull the breaker and use a meter to check for an obvious short and see if I can isolate it to a light circuit or wall outlet. Like many old houses with upgraded wiring this place has a mix of wiring types. If I don't find anything I'll put the suspect breaker into a known good circuit and try it.

I think several (all?) of the ceiling lights on this circuit still use original 1935 wiring. If the problem is inside a junction in the wall is there any trick way to isolate it? While I can get to fixtures and outlets I have no idea where/how things were done in the walls and I don't want to punch holein plaster to guess and check.

Thanks for the replies all. This happened this morning before I headed to work so I haven't had much time to look into things.

Yes, I'm comfortable working around home wiring.

Based on comments above I think my first plan will be to pull the breaker and use a meter to check for an obvious short and see if I can isolate it to a light circuit or wall outlet. Like many old houses with upgraded wiring this place has a mix of wiring types. If I don't find anything I'll put the suspect breaker into a known good circuit and try it.

I think several (all?) of the ceiling lights on this circuit still use original 1935 wiring. If the problem is inside a junction in the wall is there any trick way to isolate it? While I can get to fixtures and outlets I have no idea where/how things were done in the walls and I don't want to punch holes in plaster to guess and check.

The only reason that you would have any splices in the walls or ceilings is if you had any knob and tube wiring. Everything else should be in boxes, unless someone did a bad thing and buried a splice.

 

[FMB4]

Quote: "I know some of those lights use old metal clad cloth insulated wire". That's bad news.

Quote: "Like many old houses with upgraded wiring this place has a mix of wiring types." More bad news. Sounds like the 'upgrades' might not have been to code. I'd review the latest codes pertaining to rewiring/upgrading before you go beyond replacing the breaker (which is what I, and several others in here, recommend). Not sure if you can replace that breaker with a GFCI brkr, but you might give doing so some serious thought.

 

[Citation]

If



The only reason that you would have any splices in the walls or ceilings is if you had any knob and tube wiring. Everything else should be in boxes, unless someone did a bad thing and buried a splice.

I'm not thinking of naked splices but unseen juction boxes in the wall or in the attic under the attic floor. Happily I have seen only a few examples of Bubba doing wiring in this house.

 

[Citation]

OK, problem solved. It was the light fixture at the bottom of the stairs. I'm not sure who installed it but it was done with wire nuts that didn't have an internal spring, just plastic threading. When I pulled the fixture the nut from the hot leg was off. The underside of the light has a pad of fiberglass insulation with a foil backing. That foil appeared to be touching the exposed wire. Anyway, I inspected the cloth wire. Someone had wrapped them with electrical tape (good). I replaced the wire nuts with proper ones and all is well again. I still don't like dealing with old houses. At least the breaker did exactly what it was supposed to do.

 

[alfredeneuman]

I'm not sure who installed it but it was done with wire nuts that didn't have an internal spring, just plastic threading.

Many fixtures supplied with wire nuts for installation don't have internal springs. I throw them away.

 

[Bert_]

I'll take old wiring any day over something newer that's been butchered together. I think it actually fun working with old stuff. Interested how things were done years ago.

 

[cmandp]

Glad it was a relatively easy issue to fix. I will keep an eye for the little wire nuts that come with light fixtures.