How to find which nail shorted wires?

[bd8134]

My friend is having stucco installed on his house.
He found one room has no power and the circuit breaker trips straight away.
The contractors had removed the clapboard and banged the old nails back through, most likely hitting a cable.
How do we find "we" find which nail / nails are the culprit.
An electrican will be doing all the work, I am wondering if there is an efficient way to find the problem than just rip off all the siding like the builder wants to do.
I was wondering if there was some kind of pulse or tone generator that would work.

 

[zuk123]

There are testers that will give you the distance to the end or a break. They are called Time Domain Reflectometers and are common with network installers. If you know someone in the low voltage install industry they might be able to help you. You still need to figure out where exactly the wire is though.

A stud finder with wire detection might work for you. Make some assumptions on where the wire starts and map it thru the wall...

Or possibly something like a Fox and Hound

http://www.amazon.com/dp/B001ULPREW/?tag=atomicindus08-20

would let you find the wire, but it won't tell you where the break is.

I think you might be stuck removing the siding.

zuk

 

[pattenp]

I think you are SOL.

Edit: If the wall hasn't been recovered and the nail heads are visible you could get a very long piece of wire and check for continuity from each nail head to the circuit that's dead.

 

[bd8134]

The Fox and Hound is interesting.
I like the idea of the continuity to the nail head.
He has the electrician coming tomorrow, just see what he wants to do for now.

 

[JimVonBaden]

Tongue test!

Jim

 

[bd8134]

I thought about a nail for a fuse and check for smoke..

 

[mrb]

i would make them go back and pull out every single nail. You dont know if there are other nails that go through just the hot, could be fine now and could be a problem later. I would also be worried about a nicked wire burning through later.

 

[marty_p]

Make them re-wire that entire circuit... YESTERDAY!

 

[nehog]

Make them re-wire that entire circuit... YESTERDAY!

This is the right answer. The wiring is damaged, the insulation is damaged, and it now presents a safety hazard. You need to rewire the whole circuit (or at least the section(s) that are damaged, and not just pull the nail and pray for the best.

 

[eljefino]

If you can pull both ends of the wire at the breaker box and hook to an AC wall wart through a series resistor (light bulb) a sniffer might be able to detect the AC up to the nail but no further.

But I agree, make them rewire. Then the boss will make sure his guys don't pull this stunt again-- who knows how many other nails they've almost driven into wires? Will being a hardass avert future catastrophes like burning down a daycare? Quite possibly!

 

[Aceman]

I'd most likely use my Amprobe circuit tracer to find the short. I'd then replace that section of cable, either by adding a splice box or repulling it between the two devices. Then I'd meg the circuit when I was finished.

 

[Terry454]

At the risk of being Mr. Obvious:
This is a good argument for wire in conduit. In my area we are often criticized for our insistence on this method, but now you know ...

 

[deter]

find all devices on the circuit, start disconnecting one at a time starting from the end of the chain. Try breaker after each one. might get lucky

 

[Norcal]

At the risk of being Mr. Obvious:
This is a good argument for wire in conduit. In my area we are often criticized for our insistence on this method, but now you know ...

The conduit rule is due to organized labor/crime.

NM cable does have a good record for residential wiring....

 

[rlitman]

find all devices on the circuit, start disconnecting one at a time starting from the end of the chain. Try breaker after each one. might get lucky

That's how I would start. Identify everything that doesn't have power, open up every box, and pull out every wire. Then make a guess as to where the middle is, split the wires up, and check for resistance between hot and neutral/ground, to see which direction the short is in.

Maybe once you've got the short narrowed down to a small area, I might try to trace it with a toner and probe, but it is probably not worthwhile finding the exact location of the damage. You just need to run a new wire between the two points that the damaged wire connects. Even if you could open up the walls, and put the damaged wire in a new box, you wouldn't have enough slack to repair it.

 

[ishiboo]

The conduit rule is due to organized labor/crime.

NM cable does have a good record for residential wiring....

Amen!

 

[Terry454]

The conduit rule is due to organized labor/crime.

NM cable does have a good record for residential wiring....

Sure, until you drive a nail into it.

 

[ddawg16]

A nail will go through the armored cable with no problem....

There is a reason nail block is supposed to be used.

Another reason most of my exterior walls are 6".....

Sounds like things were done out of sequence.....the house should have been wrapped...and chicken wire installed 'before' drywall installed.

As noted....there is no real short cut to this....that section of wire has to be replaced.

 

[jbberns]

The conduit rule is due to organized labor/crime.

NM cable does have a good record for residential wiring....

organized labor/crime?
That is a stupid comment.
I think there was a big fire in Chicago years ago, that ended up putting that rule in place.

 

[Gooch]

organized labor/crime?
That is a stupid comment.
I think there was a big fire in Chicago years ago, that ended up putting that rule in place.

pretty sure conduit wasn't around in 1871, or for atleast another 50 years.


I'm an Union Electrician and I've seen drywaller's run screws through conduit plenty of times. all current wiring methods have their place, NM is GREAT for residential.

 

[ddawg16]

Here is an interesting thread on the same subject on a different forum...

http://www.electriciantalk.com/f2/conduit-vs-romex-28390/

It's pretty much common knowledge that unions were responsible for the rule....just like unions were responsible for the rule that you have to use a licensed electrician to do the work...oh yea, all the licensed electricians in Chicago are in the union.....

 

[KnurledNut]

have you tried replacing the circuit breaker itself? it doesnt happen often, but sometimes they can fail too.

 

[Norcal]

organized labor/crime?
That is a stupid comment.
I think there was a big fire in Chicago years ago, that ended up putting that rule in place.

Who do you think ran the unions??? The bosses still behave as they are part of organized crime....


The Chicago fire is used for a lot of excuses, but the EMT being used, the requirements of other areas to not use plastics for DWV & water are all union featherbedding, because they want more labor intensive methods used.

EMT is a good wiring method, NM is also has a good history for wiring homes, if some Bozo goes wild with a nail gun, EMT will not hold up, might as well require rigid conduit & cast iron boxes....

 

[jbberns]

Who do you think ran the unions??? The bosses still behave as they are part of organized crime....


The Chicago fire is used for a lot of excuses, but the EMT being used, the requirements of other areas to not use plastics for DWV & water are all union featherbedding, because they want more labor intensive methods used.

EMT is a good wiring method, NM is also has a good history for wiring homes, if some Bozo goes wild with a nail gun, EMT will not hold up, might as well require rigid conduit & cast iron boxes....

Thanks for the info. I am an officer in my local and didn't realize I was also a crime boss. That dang wool that's pulled over my eyes!

 

[bd8134]

Turned out my friend was real lucky.
He had already put in a new breaker and that also tripped straight away. I had to tell him how to remove the old breaker from the panel over the phone..
The electrican came, checked the first electrical box with a meter and said the short was going away from the panel. Opened the second box and a nail had pierced the plastic box and shorted 2 tightly packed wires inside. He repaired the wires and tested it, everything ok. He removed the nail from the outside. Luckily he did not have to get the sheeting removed to trace the problem.
I think he had AFCI breakers in his panel and in his case, the ground and white wire was shorted by the nail. If he had a regular breaker it most likely would have not have even tripped.

 

[rlitman]

Turned out my friend was real lucky.

Wow, just wow! You sure could say so.

 

[bassman]

very lucky. But to find wich nail if you were'nt so lucky, I use one of those beeping testers where it dosen';teven have to make contact on the wire and it beeps and light blinks when it senses voltage. You could haave just run it by all the nails on the outside, and you'd have found it. Glad you got it fixed without much work needed

 

[rlitman]

very lucky. But to find wich nail if you were'nt so lucky, I use one of those beeping testers where it dosen';teven have to make contact on the wire and it beeps and light blinks when it senses voltage. You could haave just run it by all the nails on the outside, and you'd have found it. Glad you got it fixed without much work needed

That would work if the nail was hot, but it wouldn't work, since the breaker was tripping.

 

[bassman]

Awe! Forgot about that. Than i guess I'd take the hot off the breaker and ground it and hit the nails with a Ohmeter to the nail and the other lead to ground. If there were a million nails to deal with, I'd start by removing devices from the affected circuit at different intervals till the br stayed on, then reconnect know where my starting point would be.

 

[JakeKohl]

Turned out my friend was real lucky.
He had already put in a new breaker and that also tripped straight away. I had to tell him how to remove the old breaker from the panel over the phone..
The electrican came, checked the first electrical box with a meter and said the short was going away from the panel. Opened the second box and a nail had pierced the plastic box and shorted 2 tightly packed wires inside. He repaired the wires and tested it, everything ok. He removed the nail from the outside. Luckily he did not have to get the sheeting removed to trace the problem.
I think he had AFCI breakers in his panel and in his case, the ground and white wire was shorted by the nail. If he had a regular breaker it most likely would have not have even tripped.

you should, errr...rush out and buy a lottery ticket...now.

 

[streetisneat]

Sorry guys but a tone will not "run" on a line with a solid short on it!