Breaker trips after 4 pm and during the summer time

[a.wayne3@verizon.net]

Here is a really good one !!!!! A home built 2 years ago sat as an inverntory home for almost a year.Then the problem started.1st service call was for tripped breaker in family room,this was recieved in late afternoon to answering service.So we sent service crew there in the am.
Breaker was holding fine.A couple of weeks passed
Another call same thing again we sent service .Same thing no defect found :roll:
A couple of weeks go by same thing.So I went there to take a look sure enough the breaker was tripped.Continuity check showed all conductors clear,this was around 1 pm.I changed the breaker figuring maybe it was just a weak breaker.That eve another call breaker tripped again.I had informed service that if another call was recieved I was to be called.I got there around 5 pm and breaker was tripped and when i reset it it tripped again i opened the circuit up and checked all conductors they now showed no hot to ground continuity btw this is nm 12/3 installation for switched receptacle.By this time now I am confused,I reset breaker and it holds.I use a toner alot so i left the power on all devices pulled out of boxes and started checking.Then I found it 1/2 way between 2 receptacles the toner started to buzz loudly when i passed over the baseboard at a seam.I informed homeowner that I had to cut the drywall there.By this time she didnt care if i ripped the wall down.Builders warranty still in effect.When i cut drywall just over the base there it was a finish nail had penetrated the 12/3,I cut the nail and a section of affected wire out.The nail had gone almost completely through the hot and had grazed the neutral.So why only in the afternoon does this happen ??????????The only thing I could figure was that during the day the heat built up in the block wall and expanded the metal from both the finish nail and the nm contact made and bam tripped breaker.Service crew was there with me I had them change the affected wire and no more problems ....... By the way this area here Hillsboro county allows nm to be staples to top of 1x4 or wider pt that is nailed to the block,with out stand offs or stackers as some call them......

 

[bennie]

Re: Breaker trips after 4 pm and during the summer time

Good job of troubleshooting. This issue may be caused by some kind of movement in the building or the cable. It could be the wake up time for the resident mouse also

 

[electricmanscott]

Re: Breaker trips after 4 pm and during the summer time

I would go with the building movement-expansion theory.

 

[charlie]

Re: Breaker trips after 4 pm and during the summer time

consider the same situation with stud construction and a little less contact. An AFCI would be tripping and saving the house from a fire. Some places are dropping the requirements for AFCIs and they are not required for all circuits . . . HMMM.

 

[daveselectric]

Re: Breaker trips after 4 pm and during the summer time

The breaker trips in the late afternoon after there is heat build up on the exterior wall. The A/C is running at full blast and while the walls are insulated, condensaton may build up and cause the circuit to fault.

 

[templdl]

Re: Breaker trips after 4 pm and during the summer time

It has to worth at least 5 credits in continuing education. Good job!!

 

[Guest]

Re: Breaker trips after 4 pm and during the summer time

Not getting the complete picture but my mental picture is wondering if "notch" plates or cable "protectors" (those flat metal) plates would have stopped the baseboard from being nailed through the wire. I am a notch plating fool! If it looks suspicicous, I plate it. Better safe, than sorry.

 

[Guest]

Re: Breaker trips after 4 pm and during the summer time

Oh, and I saw a similar situation behind a toilet where a baseboard finish nail punctured the copper toilet supply and made it leak a bit everyday when the afternoon sun hit that wall. Talk about Poltergeist!

[ This cybercom was Spell Check with ieSpell before submission: http://www.iespell.com ]

 

[big john]

Re: Breaker trips after 4 pm and during the summer time

I dealt with a similar case where a family had just finished renovating a bathroom and was complaining that every time they'd just gotten out of the shower and went to touch the sink or the toilet, they'd get a light shock.

At first, I assumed it was a bonding problem, but couldn't find any voltage gradiants across anything. Everything in the bathroom was fed on the same circuit, GFI protected at the panel, so after testing the GFI, I'm starting to rule that out, thinking that anything strong enough to shock these folks would cause a trip.

Not sure what to do next, I just fired up the shower to see what in the world they were talking about. Put it on hot, let it run for a while, and went in and just started taping things here and there to see if I could pick anything up. I'll be damned if I didn't start getting little bites. I go over and touch the metal flush-knob on the toilet and it hits me pretty hard, so I go and shut off the breaker come back up and the problem still exists. I'm looking all around this toilet for the problem. Supply line is copper all the way back to where the cold water line is bonded to the panel, I don't see why in the world this thing has a potential on it. I'm down on the floor looking at it, and my hand touches the wall and I get lit up! :roll:

-John

[ October 02, 2003, 08:11 AM: Message edited by: big john ]

 

[a.wayne3@verizon.net]

Re: Breaker trips after 4 pm and during the summer time

AWWT I agree nail plates are invaluable,but this jurisdiction allows the nm to be stapled directly to the top of the 1x4 or wider base wood that is nailed to the block.We work in several different jurisdictions here and all but hillsboro county do not allow this installation,all others require
that nm be in accordance with 300.4 d. Hence standoffs or staple to the furring bottoms and nail plates are required.If you have never used one of these type toners with a signal generator and reciever stick get one !!!! aside from tracing wires with the signal generator attached
they can detect live wires that are open (ie) burried by drywall or cut or as in this case penetrated.They buzz loudly when they pass over an open live wire.I also agree that if this was an afci circuit this would have never gotten this far.The nm that was removed looked as if it was used for target practice.There were arching marks all around it.Almost 30 years in the trade and i see new things all the time ,so this continued my education.....So it is possible to teach old dogs new tricks