AFCI trips

[MannyBurgos]

Installed GFCI breaker--no tripping.
Re-installed the AFCI breaker.
Took apart every connection on the circuit.
Reconnected everything one wire at a time, had my helper turn the breaker on after each re-connection was made. Everything held no problem.
Installed the light fixture (on a 3-way switch) turned breaker on and POP! It tripped.
Removed fixture, installed a pigtail and incandescent light bulb. POP!
Removed the pigtail and light bulb, reset the breaker turned it on and POP!

Installed a regular CH115 breaker, closed the panel, said I would return next week to the customer, got in my truck, and :rant:

I'm at a loss!

You have it tracked down and are very close. Seems to me the problem is associated with the switches. I would disconnect all wires from 3 way devices and start connecting one by one while verifying if afci trips. You had the problem right there in your hands but sometimes it is better to leave then to start ripping stuff apart. Smart man. Also make sure that the light fixture neutral is not spliced in with olanother circuit at the box. Ive seen jobs where neutrals are all spliced together with other circuits. But first, start with device troubleshooting.

 

[ELA]

Installed GFCI breaker--no tripping.
Re-installed the AFCI breaker.
Took apart every connection on the circuit.
Reconnected everything one wire at a time, had my helper turn the breaker on after each re-connection was made. Everything held no problem.
Installed the light fixture (on a 3-way switch) turned breaker on and POP! It tripped.
Removed fixture, installed a pigtail and incandescent light bulb. POP!
Removed the pigtail and light bulb, reset the breaker turned it on and POP!

Installed a regular CH115 breaker, closed the panel, said I would return next week to the customer, got in my truck, and :rant:

I'm at a loss!

Hello Tshea,
Can you clarify your next to last last line test description it sounds like the breaker trips with no load ( was the 3-way activated or not?)

What occurs to me is; how long are you testing for, after making a change to the test conditions ( duration of each test when the breaker is appearing to hold)?
Sometimes when troubleshooting, transient conditions are not always present, and one can make an incorrect assumption about a test result by not allowing enough test time after each change made. I know I have been guilty of this especially when I was in a hurry.
Also be sure that you are only changing one variable in the test at a time. A test condition matrix can be helpful for that.
When test results do not make sense it may pay to allow more time before making a conclusion about a test condition change. This can be especially true when having AFCI nuisance trips.

 

[tshea]

Solved!

Solved!

Neutral from another circuit was tied in with the AFCI circuit. It was a long roundabout way of being connected. Suffice it to say, a new circuit was pulled in for the second neutral wire. It did not have a home.

Thanks for all the help. I suppose AFCI's will help save somebody some day.

 

[Ponchik]

If you have multy-gang switch boxes, with more than one circuit in them, I have found that some are still splicing all of the neutrals together, you must keep the neutrals from separate circuits separate. Mix them in any way and the AFCI will tripp.

Leo wins the prize. :thumbsup::thumbsup:


OP good job on the troubleshooting and finding the problem. I am sure you had a big smile on your face.

 

[Little Bill]

Neutral from another circuit was tied in with the AFCI circuit. It was a long roundabout way of being connected. Suffice it to say, a new circuit was pulled in for the second neutral wire. It did not have a home.

Thanks for all the help. I suppose AFCI's will help save somebody some day.

Great that you found the problem!

But you do know that the AFCI function alone wasn't what detected the two neutrals. Also the fact that two neutrals were shared wasn't a safety concern. It was the GF portion of the AFCI that detected it. A GFCI would have detected that.
So the jury is still out on whether an AFCI, independent of the GF portion, will do what they claim/expect them to do!