Got a call to a house that recently had foam insulation installed in the exterior walls via drilled holes from the outside. Product was shot into the stud cavities, it expands somewhat, then dries. Before the work was even completed a circuit breaker tripped and power was lost to 2 rooms.The installer removes a recep from a box in one of the walls in question and finds that the foam has penetrated into the box(all boxes metal and grounded) he removes it and puts the recep back in. Breaker is reset and stays on for several hours then trips. I arrive 3 days later and the homeowner and I go to the panel , he attempts to reset it twice and it fails, I reset it and it holds. As I'm looking around one of the rooms in question it trips, reset's instantly and stays on for about 30 seconds and trips again. Again I reset it and put a meter on it and it's drawing about 1 amp(ceiling fixture in 1 room is on)we B/S for about 5 minutes and it trips again. Any clues at all, I can come up with several reasons if it would act consistently, but the randomness has got me scratching my head. Thanks.
Head scratcher
- Thread starter nizak
- Start date
- Status
VoltzElectric
Member
- Location
- Hudsonville Michigan
Have you tried replacing the breaker?
You could try removing devices off circut, and ring out from box to box, and check to see if they are grounded
Could have a bad device hooked up?
You could try removing devices off circut, and ring out from box to box, and check to see if they are grounded
Could have a bad device hooked up?
TwinCitySparky
Senior Member
- Location
- Minnesota
ptonsparky
Tom
- Occupation
- EC - retired
Have the customer keep resetting the breaker. The fire investigator will find the fault for them.
ceb58
Senior Member
- Location
- Raeford, NC
This could be a clue.
Were you expecting the results to be different each time. You have reset this breaker 5 times and it did not hold. Its time to get the megger out and find where the problem is.
ptonsparky
Tom
- Occupation
- EC - retired
No. The amount of carbon and conductive material or path has changed after each fault. At the very least the wire moves a grunion each fault.
ceb58
Senior Member
- Location
- Raeford, NC
There is a pattern. It keeps triping.:grin: There could be a nick in the wire and the moisture in the insulation is acting as a conductor to ground. Or the same with another box filled with insulation.
This would also be an area of concern. Why did the HO allow a insulation installer to start removing electrical devices.
One thing you have not stated is it a standard breaker or a AFCI
Every time the cb is reset and trips it will weaken and act different the next time, every
time the 'short' trips the cb the wires get damaged more and will act different, the
inconsistent aspect of the problem is consistent with the pattern of action.
electricmanscott
Senior Member
- Location
- Boston, MA
I'd also bet damaged wire.
A damaged cable drenched in foam could be trouble. That paper inside the sheath will never dry out.
As mentioned that moisture can be just enough to create a path to ground. I have seen it happen with my own two semi good eyes.
A damaged cable drenched in foam could be trouble. That paper inside the sheath will never dry out.
As mentioned that moisture can be just enough to create a path to ground. I have seen it happen with my own two semi good eyes.
We have had problems with the foam installers scraping the excess off the front face of the studs and they let their wide scraper get into the romex.Appearantly when the inslation expands it has a tendency to harden up and push some of the wires toward the front due to the expansion of the foam.We use cable stackers and staples and wire ties.We always pull our wires tight and they are flat against the framing members.The contractor was informed by the insulator that they had gotten into a couple wires,luckily we were able to repair this before the wall board was installed.Megger--and a process of elimination is the only way to pin point your problem.
Cow
Senior Member
- Location
- Eastern Oregon
- Occupation
- Electrician
Megger it, unless the gameplan is to try and blow the fault clear by resetting the breaker multiple times...
macmikeman
Senior Member
- Location
- Planet macmikeman
Odds of a failed QO115 breaker- .000000001%. Odds of a drilled wire 90%. Better not report back on your findings, or the CMP's get wind of this and we will be casing in the structure exteriors with #12 guage sheet metal by 2014......
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