I need help with knowing how to diagnose an arc fault issue. In particular, are there resistance measurements I can be marking to isolate the problem?
I’ve finished the rough in on a residential remodel job. It was such an extensive remodel with a lot of customization that it required about 85% total rewire. A new sub panel was installed (Leviton LP310-MB).
I energized two 20 amp circuits (AFCI+GFCI breakers) to give the other trades some power for tools and battery chargers. And I energized two 15 amp circuits (AFCI breakers) for temporary work lights. The fixtures I’m using are the temporary, hard wired sockets with an LED lamp screwed in.
Everything has worked flawlessly for a several weeks. The GC called me and said that one of the lighting circuits had an arc fault trip. I went out to the job site, reset the breaker and couldn’t get it to trip. On this circuit there is only one temporary light fixture. I left it on and headed out to another job. I swung back to that job site and the breaker had tripped again. I reset it, wiggled the wires in the switch box, went into the attic and wiggled several (but not all) nm cables that are on that circuit. I could not get it to trip. My assumption is that it’s not a screw in a wire from the drywall crew because it’s not tripping instantaneously. With only one LED lamp it certainly can’t be an overload.
The circuit feeds from the panel to a j-box in the attic. I disconnected all other branches that feed out of this j-box except for the the one that feeds into the box with the light switch. I’ll be heading back there to see how it’s faired overnight.
I’ve not yet replaced the breaker. I’ve heard about replacing the AFCI breaker with a GFCI breaker incase there is a low level leak to ground because a GFCI breaker will trip faster than the AFCI breaker. Since I finished the rough in there have been other changes to the scope that involved opening a portion of the roof and they had a rapid storm form and which dumped good amount of rain water in one section of the house. Could it be that a J-box has some moisture in it that is causing a low level fault to ground?
Are there measurements I can be making with my multimeter to help isolate where the issue may be? Any other tips?
Thanks for your help.
Sent from my iPhone using Tapatalk
I’ve finished the rough in on a residential remodel job. It was such an extensive remodel with a lot of customization that it required about 85% total rewire. A new sub panel was installed (Leviton LP310-MB).
I energized two 20 amp circuits (AFCI+GFCI breakers) to give the other trades some power for tools and battery chargers. And I energized two 15 amp circuits (AFCI breakers) for temporary work lights. The fixtures I’m using are the temporary, hard wired sockets with an LED lamp screwed in.
Everything has worked flawlessly for a several weeks. The GC called me and said that one of the lighting circuits had an arc fault trip. I went out to the job site, reset the breaker and couldn’t get it to trip. On this circuit there is only one temporary light fixture. I left it on and headed out to another job. I swung back to that job site and the breaker had tripped again. I reset it, wiggled the wires in the switch box, went into the attic and wiggled several (but not all) nm cables that are on that circuit. I could not get it to trip. My assumption is that it’s not a screw in a wire from the drywall crew because it’s not tripping instantaneously. With only one LED lamp it certainly can’t be an overload.
The circuit feeds from the panel to a j-box in the attic. I disconnected all other branches that feed out of this j-box except for the the one that feeds into the box with the light switch. I’ll be heading back there to see how it’s faired overnight.
I’ve not yet replaced the breaker. I’ve heard about replacing the AFCI breaker with a GFCI breaker incase there is a low level leak to ground because a GFCI breaker will trip faster than the AFCI breaker. Since I finished the rough in there have been other changes to the scope that involved opening a portion of the roof and they had a rapid storm form and which dumped good amount of rain water in one section of the house. Could it be that a J-box has some moisture in it that is causing a low level fault to ground?
Are there measurements I can be making with my multimeter to help isolate where the issue may be? Any other tips?
Thanks for your help.
Sent from my iPhone using Tapatalk