Vexing Electrical Problem

[Dennis McDonaugh]

I didn't get to work on it yesterday, but with both light and fan switches disconnected in the bedroom the circuit doesn't immediately trip, but will after a period of time whether you use any other device or light in the house. Sometime it trips fairly quickly and other times not for hours. Nothing is plugged into any of the outlets on the circuit.

Today I am replacing both switches in the bedroom and rewiring all the outlets and light fixtures. After that I'm at a loss.

[Dennis McDonaugh]

I disconnected the antique light fixture in the kitchen and the light in the hall. The hall light is on a 3-way switch if that makes a difference. The breaker hasn't tripped so far.

None of the outlets have anything plugged into them much less anything powered
The bedroom fan and light switches are disconnected
The hall and kitchen light fixtures are removed

These items are powered
outlets
two hall light switches
foyer light and switch
kitchen light switch

I figure process of elimination is my best bet now.

[Pat Barry]

I figure process of elimination is my best bet now.

Yes - I agree - good luck

[Mike Lassiter]

I have a different perspective than some of the other posters. If an AFCI breaker is tripping, and you've replaced the breaker and the new one still trips, you have a problem in the circuit that needs to be addressed.

Replacing the AFCI with a standard breaker will not solve the root cause of the problem, but it could allow an electrical fire to occur that would be prevented by the AFCI.

Six years ago I lost my woodshop due to fire - most likely caused by an electrical short. Standard breakers do not trip due to arc faults, and both the Fire Inspector and myself believe that an arc fault was the root cause of the fire.

I would strongly discourage you from replacing the AFCI with a regular breaker. Instead, trace down the cause of the tripping and address it.

Some time back our refrigerator started acting up. Open the door and the inside light sometimes would be very dim, other times it was bright but would be erratic in light output. I thought the bulb was "going bad", but didn't really think too much about it. The refrigerator is the last receptacle on the counter receptacles in the circuit. I cannot exactly recall now why I did this or what caused me to; but beside the refrigerator sits a Kitchen Aid mixer that basically stays plugged in all the time. I removed the power plug from the receptacle to find the molded plug was discolored from white to a brownish color. But the real shocker was the receptacle itself was black and melted. The plug on the mixer had prevented this from being seem.

When I removed the face plate and the receptacle I found wires had become loose at the screws holding them ( lived here about 14 years at the time ) and with the current draw from the refrigerator being supplied by the wires on this receptacle it was causing heat to build up. It had already got the wire hot enough that the insulation had melted about an inch or so from the naked wire. This was just before burning our house down. With the mixer plugged into the wall receptacle you couldn't see the heat caused damage. I think I noticed the mixer plug being discolored was the reason for investigating further and finding this.

With that said I have to agree with Scott! DONOT take this lightly. Something is not right, and while changing the breaker out for a non Arc Fault style may stop the breaker from tripping it may also cause your house to burn up. I don't want to hear about that happening! I think you are on the right track investigating this to the best of your ability and if you come up empty handed I suggest you call in someone.

Good luck.

Wall recptacle.jpgRecpt out.jpgrecpt back.jpgMixer plug 1.jpg

[Dennis McDonaugh]

I agree with you Mike. Right now I'm just trying to disconnect something that will make it stop blowing the breaker! So far so good today.

[Dennis McDonaugh]

I picked up a couple 20 amp switches--overkill I know, but right now I'm more interested in stopping the issue than saving money. I'll replace them tomorrow, hopefully after the breaker doesn't trip today.

[ray hampton]

Ray, they are regular light fixtures and all but one has a CGL light bulb, the other has a incandescent. The one with an incandescent light is an antique and has a two wire light fixture retrofitted, I added a ground to the metal fixture years ago. It has been operating with no issues for almost a year, but its the first light fixture I would suspect of causing the problem if the light switch in the bedroom didn't immediately trip the breaker.

I doubt that the switch are bad more likely a wire going to /from the switch are going to ground, the wire could be at a light or other device

[Dennis McDonaugh]

[/COLOR]
I doubt that the switch are bad more likely a wire going to /from the switch are going to ground, the wire could be at a light or other device

By disconnecting the light at the switch I can eliminate the wire from the switch to the light. I can't do much about the wire from the breaker to the first switch or outlet.

[Dennis McDonaugh]

tripped again dang it

[Dennis McDonaugh]

Looking at the link Pat provided, I see my symptom is listed in category C, AFCI trips between 1 minute and 1 month. There are 3 causes given, overload, bad breaker and arc fault. Obviously the circuit is not overloaded, it trips with nothing connected to it. I don't think the breaker is bad since I replaced it and got the same symptom with the second one. That leaves an arc fault which is hard to find. I can make sure all the outlets, lights and switches have good connections, but can't access anything in the walls.

[Chris Padilla]

Interesting albeit frustrating problem. I would think a bit and search a bit on what exactly is entailed and involved with an "arc fault" on the breaker. It might help you track down the culprit if you understand the common causes of an arc fault. Loose connections are an obvious one but assuming you've taken care of that, what else causes them?

[ray hampton]

Dennis , this will sound crazy BUT do you have bugs or animals in the wall that may be in contact with the wires

[Mike Lassiter]

Looking at the link Pat provided, I see my symptom is listed in category C, AFCI trips between 1 minute and 1 month. There are 3 causes given, overload, bad breaker and arc fault. Obviously the circuit is not overloaded, it trips with nothing connected to it. I don't think the breaker is bad since I replaced it and got the same symptom with the second one. That leaves an arc fault which is hard to find. I can make sure all the outlets, lights and switches have good connections, but can't access anything in the walls.

I maybe wrong BUT (that never stopped me) I am thinking arc fault too. I don't see how you could have a arc within a circuit if nothing is drawing current of some degree. Just having a loose connection in the circuit shouldn't arc with no load as there isn't a complete circuit to anything. I suggest you have something else in this circuit still that you haven't identified yet being apart of it. The only other thing comes to mind would be perhaps water has gotten into something, but not sure how or if that could do it.

You mentioned about disconnecting a light switch to kill power to a light. This brings a question to mind. Is the power for the light from the box the light switch is located in, and the wire from the switch is sending power to the light, or is it a "switch leg" that is getting power in the box the light itself is in, and being feed power from the light to the switch and back to the light to complete the circuit? Assuming you are turning off breaker to disconnect wires on the switch, then turning breaker back on - if power is coming from the light to the switch you have one of the two wires between the light and switch hot regardless of the switch being on or off that could be the problem area.

[Mike Lassiter]

I disconnected the antique light fixture in the kitchen and the light in the hall. The hall light is on a 3-way switch if that makes a difference. The breaker hasn't tripped so far.

None of the outlets have anything plugged into them much less anything powered
The bedroom fan and light switches are disconnected
The hall and kitchen light fixtures are removed

These items are powered
outlets
two hall light switches
foyer light and switch
kitchen light switch

I figure process of elimination is my best bet now.

It could depending on which way it is flipped. You have to have 3 wires for 3 way switches to work. As I was taught one is a "traveler" that connects the two switches together so regardless of which switch is used power will still get to the load. So if you regularly use the same switch one wire is sort of out of the loop until the other switch is flipped and them it would come into play. Don't know if my remarks are explaining what I am trying to say exactly, but with a single switch that switch will always be the point the power is switched on or off. If you have 3 way switches you have to replace a simple on/off with another 3 way and have two of them for the circuit to work. Power will go from one switch to the other thru the extra wire which could be a problem if something is loose. Not sure it would/could if you had the light removed as again no load, nothing to arc with a open circuit unless a short type connection.

[Dennis McDonaugh]

disconnected the foyer light at the ceiling, no trips for 3 hours