Need Help

[Worlds Gr8est Electrician]

I need help. I have a circuit that has a square D Qo AFCI breaker on it. I wired this house. The circuit worked fine for 2 months. Now it trips anywhere from one day to three days. No one particular thing makes it trip. The circuit has these items on it.


USB outlet


less then 10 receptacles


foyer light


2 ceiling fans


switched GFCI


4 outdoor sconces


The circuit has no shared neutrals and I have pulled the entire circuit apart and checked everything. Nothing looks wrong at all. I even used the siemens arc fault testing tool and nothing showed any signs of arcing. Am I missing something?

 

[charlie b]

I would tend to question this statement:

No one particular thing makes it trip.

How would you know that there is not one single culprit? If one of the receptacles has a problem, either internal to the device or on the item plugged into that receptacle, and if that problem causes a high current to flow, but not high enough to trip the breaker by itself, then perhaps today the circuit trips when they turn on a light, and tomorrow it trips when they turn on the TV, and the day after it trips when they run the vacuum cleaner. Perhaps that is why they haven't been able to tell which thing causes the trip. But it is still the one receptacle that is the cause, it's just not enough of a cause to trip the breaker all by itself.

I would suggest giving the homeowners a homework assignment, something along the following lines:

• Step 1: For the first week, or until the breaker trips, leave the sconces turned off.
• Step 2: For the second week, or until the breaker trips, feel free to use the sconces, but leave the foyer light and the ceiling fan off.
• Step 3: For the third week, or until the breaker trips, feel free to use the sconces and the foyer light and the ceiling fan, but do not plug anything at all into 5 of the 10 receptacles. Use extension cords if necessary, but leave those 5 alone.
• Step 4: Same as step 3, but do not use the other 5 receptacles.

The idea is to isolate the problem, and they don't need to pay you (or have you work on your own time) to get through this isolation process.

 

[ceb58]

You could start by switching it with another one in the panel to see if that particular breaker keeps tripping. Or just replace it with a new one and see what happens. I chased one for 2 months until the HO's finally told me it would do it when the phone answering machine picked up. It was an old type that had the small cassette tape in it. When it started it would go forward, then backwards and then start recording. The back and forth was causing an arc in the machine.

 

[Worlds Gr8est Electrician]

I would tend to question this statement: How would you know that there is not one single culprit? If one of the receptacles has a problem, either internal to the device or on the item plugged into that receptacle, and if that problem causes a high current to flow, but not high enough to trip the breaker by itself, then perhaps today the circuit trips when they turn on a light, and tomorrow it trips when they turn on the TV, and the day after it trips when they run the vacuum cleaner. Perhaps that is why they haven't been able to tell which thing causes the trip. But it is still the one receptacle that is the cause, it's just not enough of a cause to trip the breaker all by itself.

I would suggest giving the homeowners a homework assignment, something along the following lines:

• Step 1: For the first week, or until the breaker trips, leave the sconces turned off.
• Step 2: For the second week, or until the breaker trips, feel free to use the sconces, but leave the foyer light and the ceiling fan off.
• Step 3: For the third week, or until the breaker trips, feel free to use the sconces and the foyer light and the ceiling fan, but do not plug anything at all into 5 of the 10 receptacles. Use extension cords if necessary, but leave those 5 alone.
• Step 4: Same as step 3, but do not use the other 5 receptacles.

The idea is to isolate the problem, and they don't need to pay you (or have you work on your own time) to get through this isolation process.

What I meant was it was not one thing like when you walk in the room and flip a light on it trips.


The circuit never trips when they are doing something. In fact it is usually when they are not even in the room.

 

[under8ed]

What I meant was it was not one thing like when you walk in the room and flip a light on it trips.
The circuit never trips when they are doing something. In fact it is usually when they are not even in the room.

They may just not realize it. If they walk into the room & switch a light on, how would it be known if that's what tripped it. They may assume it had already been tripped. If there was a small lamp on that circuit, always left on, placed in a prominent location with an extension cord, it may help them to pinpoint when it trips. I would also swap the breaker with another as suggested.

 

[cadpoint]

You need to go rent one of these


DCT419S1
Hand Held Wall Scanner

http://www.dewalt.com/tools/cordless-instruments-radar-scanning-dct419s1.aspx

 

[hbendillo]

Is there a particular time of day or night it trips? Seems like a lot of devices and equipment for one circuit. When you say less than 10 receptacles, how much less? 9? 8? I wouldn't connect that many receptacles to a circuit let alone other devices. Like Charlie b is saying, could be an intermittent overload.

 

[ActionDave]

I need help. I have a circuit that has a square D Qo AFCI breaker on it. I wired this house. The circuit worked fine for 2 months. Now it trips anywhere from one day to three days. No one particular thing makes it trip....

Am I missing something?

You may not be. I have seen AFCI's trip on circuits I know are clean and not overloaded. Two brands of breaker, SqD and GE. Both times it was electronic loads that caused the trip.

Swap breakers in the panel, try a new breaker, and call Sq D. One member here said he had luck exorcising the demons out of the breaker by adding about 20' of extra wire to the circuit inside the panel.