MDShunk

Did a service call last week where the homeowner reported that the lighting circuit for the second floor was off and the breaker wouldn't reset. Home was wired in conduit, and she reported that they just had a new flat rubber roof installed. I pretty much already knew what I was going to find.

I took all the switchboxes apart in the affected circuit, and took all the fixtures down. I wanted to get an idea of how all the pipe was run to limit damage from any future "exploration". By ringing things out, I determined that the shorted section of pipe was over the second floor bathroom, and I also was pretty sure that there was at least one buried junction box.

I found the elusive junction box above a recessed 1' x 4' fluorescent fixture in the bathroom. As luck would have it, I found one screw into a conduit right there. I drilled a hole in the rafters through that fixture opening in the ceiling and used the snake camera to fine one more screw through a pipe.

With both screws through pipe located, I made repairs, megged the circuit to be sure everything was found, and put the place all back together. Her 10K rubber roof cost the roofer pretty dear. In his defense, there's not a thing they can do about it other than hope they don't hit a pipe.

First picture is of the junction box I found above the recessed fluorescent vanity light fixture. Second pic is a roofer's screw partially in a pipe that was in that opening. Third pic is a cell phone picture of the image on the camera screen (upside down) of a roofer's screw completely through a pipe.

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B4T

Nice troubleshooting how did you make repairs with screws you can't take out? I would guess you ran NM between junction boxes.

MDShunk

I had three rafters to get through, on 16" centers, to get from that junction box that you see in the picture to another junction box I was able to access through the opening gained by removing a bath fan. The conduit had 5 conductors in it (hot, neutral, two travelers, and a switched hot). I just drilled from the recessed light opening with a nail eater bit and kept adding extensions until I got to where I needed to be. Pulled a piece of 1/2" Greenfield as a replacement for the EMT, and abandoned the EMT in place.

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One reason not to give DIY advice:
Catch a man a fish and you can sell it to him.
Teach a man to fish and you’ve ruined a good business opportunity.

Rockyd

Wait till I tell Peterd that you're his latest student !

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william1978

Screws run into conduits like that is why we have 300.4 (E) now in the 2008.

spark teacher

I have never registered on this site, but I read things a lot here. I had to register today to say that's an amazing piece of work. Class is on summer break now but I am going to print this one out for later use.

william1978

Welcome to the forum spark teacher.

aksparky

I can see where that snake camera you have is a pretty darn useful tool, not only in finding the problems but also in presenting the evidence to the home owners when they complain about a service call that in their opinion takes too long.
Nice post.

wirenut1110

Ah ha, now I know why this post was on CT.

http://www.contractortalk.com/f5/con...of-deck-59767/

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Jim

Frasbee

I've never really seen EMT inside a house.

MDShunk

There was one particular builder in my area who built homes from the mid 50's to the early 80's. Most of them were wired in pipe. It was a selling point, I believe. They're mostly higher end homes.

__________________
One reason not to give DIY advice:
Catch a man a fish and you can sell it to him.
Teach a man to fish and you’ve ruined a good business opportunity.

MDShunk

Yeah, I think there was something like 9 or 10 electrician hours and 3 or 4 helper hours involved in this. I forget exactly. I vaguely remember from making up the bill the other day. Not much material. As with so many service calls, the labor generally exceeds the materials by a substantial margin.

__________________
One reason not to give DIY advice:
Catch a man a fish and you can sell it to him.
Teach a man to fish and you’ve ruined a good business opportunity.

Magnettica

Damn roofers!

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MDShunk

That would be sorta funny if it was the same guy, but I doubt it. This happens with certain regularity.

__________________
One reason not to give DIY advice:
Catch a man a fish and you can sell it to him.
Teach a man to fish and you’ve ruined a good business opportunity.

Peter D

So you're not a superhuman after all. It actually took you quite a bit of time to find this problem.

MDShunk

Correct. Most of that time was due to not wanting to destroy the place. That would have resulted in an even bigger net bill for the customer after she hired a carpenter, plasterer, painter, etc.

__________________
One reason not to give DIY advice:
Catch a man a fish and you can sell it to him.
Teach a man to fish and you’ve ruined a good business opportunity.

Peter D

But that takes all the fun out of it.

Where they aware they would be in for such a whopping bill?

MDShunk

They already had arranged with the roofer to have an electrician look at it on his dime. I also gave them the head's up that I fully expected to find at least one screw through the wiring. I honestly don't know if they expected this much or not, but their lights work now. I kept them in the loop throughout the troubleshooting process, which I believe is vital during any extensive trouble call in someone's home. Always, always keep them up to date on what you've checked so far, what you've found so far, what you have left to check, and what else you expect to find. That's so critical.

__________________
One reason not to give DIY advice:
Catch a man a fish and you can sell it to him.
Teach a man to fish and you’ve ruined a good business opportunity.

waco

This is becoming a real problem and I'm a little bit confused as to why it is happening. I have had some extra deep plastic boxes hit from the backside. Heck, they force the wires to be closer than an inch and a quarter to the face of the framing member, but they are legal.

It is my understanding that even conduit is supposed to be at least an inch and a quarter in from any surfaces, yet I see jobs like that you pictured, conduit mounted right on plywood or OSB with fasteners coming in from the other side, nailing the conduit.

Good job of troubleshooting.

MDShunk

That wasn't the case until the 2008 NEC. The installation I have pictured is from 1956.

__________________
One reason not to give DIY advice:
Catch a man a fish and you can sell it to him.
Teach a man to fish and you’ve ruined a good business opportunity.