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A must read post !!

Posted By: HCE727

A must read post !! - 05/09/08 05:09 PM

A customer from a row home calls me and tells me that he received a good shock, while in the shower, as he was adjusting the shower head. He also tells me he smells something burning in the basement. I will just state the facts, to keep this as short as possible.
Facts: 1st day
60-volts from soil pipe to cold water pipe.
No-hub fittings on soil pipe are melting and stainless clamps are glowing.
Turn off all breakers, one at a time, still getting voltage.
Out back of property, test down spout, that is emptying into soil pipe, to cold water spigot get 120v with all breakers off.
Service is 100a cable, sleeved in non-grounded emt, 100-a cable is twisted and smashed, in a lb, going into the house.
Most house's on the block are brick, stucco, with a 2nd floor bay, that is AL siding, siding is in contact with the stucco wire and stucco, all windows and barge boards are capped in AL.
Conclusion: Service cable is in contact with stucco wire, traveling to siding? Going to replace service cable on 2nd day.
Facts: 2nd day
First thing,test down spout, no voltage.
Neighbor next door asks to check a breaker that has tripped, reset breaker.
Back to next door, disconnect one leg at taps,get 120v, disconnect other leg, still get 120v, disconnect neutral and no-hub fittings catch fire, re-connect neutral.
Fire dept. and PECO on there way!
Peco tests neutrals in both houses, everything is fine.
What could it be?






Posted By: gfretwell

Re: A must read post !! - 05/09/08 07:09 PM

Did the problem go away after the PoCo said there was no problem on their side? It sure sounds like a neutral open and the pipe system doing all the work
Posted By: EV607797

Re: A must read post !! - 05/09/08 08:07 PM

Henry, am I safe to assume that the services are overhead?

My next question is: Have any homes had new cable TV, satellite or Verizon FIOS service installed recently?

Posted By: HCE727

Re: A must read post !! - 05/10/08 01:23 AM

Peco said that the neutrals were ok on their side, still getting 120v on down spout. I do not know of any new cable tv installs on the street. All services are overhead, one feed along the back of the houses. I have the answer, I was trying to see if anyone could guess what it was.
Posted By: dura101

Re: A must read post !! - 05/10/08 01:57 AM

Well I guess it must have something to do with the tripped breaker at the neighbour's house. Easy fix, just tell the neighbour that they can never turn that breaker on ever again, lol. Just kidding.

You say that when their breaker was tripped you had no voltage. Then when you reset it you had voltage from the downspout to the cold water pipe.

Did the neighbour's hot from that circuit come into contact with the downspout or something else that is bonded to it? Nail or something?

Posted By: jdo1942

Re: A must read post !! - 05/10/08 10:27 AM

I think what you have is a source that has a bad neutral connection and is using any available ground to provide a neutral reference, hence a large amount of unbalanced current coming thru the grounds to get to a neutal. The cast iron sewer pipe can provide a ground.

Joe Ogle
Posted By: renosteinke

Re: A must read post !! - 05/10/08 02:56 PM

I think that the one breaker seems to control the problem is a major hint. The problem almost has to be on that circuit.

Enough current to melt the no-hub connectors? I'm impressed. I suspect that neighbor has a few problems. Here are some ideas:
First, I'd find out what's on the circuit. Then, I'd see if the problem persisted with every appliance unplugged. This removes the appliances as the source of the problem. (I don't think they are, but let's stop guessing, and be systematic).
The next step is finding the place in the circuit where the hot contacts a pipe, the conduit, or whatever. A cheap megger is a good tool to use to check the wires.

You notice I am not thinking "neutral." Not, at least, if the problem persists without any appliances plugged in. Since you claimed to measure 120v at one point, I don't think that current is flowing through any load.

Once you find the short to ground, you've found half the problem. The other half? Grounding.
I suspect that the neighbor has a good water bond ... it might even be to the sewer line. I also suspect that your customer has a poor one. I doubt either house has a ground rod.

Keep this in mind: The only way the piping can become energized is if there is no path for the electricity to get back to the PoCo transformer.
Posted By: walrus

Re: A must read post !! - 05/10/08 05:53 PM

I can't see how the SS clamps would glow?? Aren;t they insulated from the pipe by the rubber sleeve inside the no hub?? Maybe the rubber burned away?
Posted By: renosteinke

Re: A must read post !! - 05/10/08 09:22 PM

Walrus, from the OP's description, I was making the guess that there was arcing between the two pipes. Heck, since those connectors typically have a foil-like wrapper, the clamps and foil may be the primary current path.

Too bad most amp clamps aren't big enough to go around a sewer line!
Posted By: Trumpy

Re: A must read post !! - 05/10/08 10:14 PM

Just a little thought.
This sort of sounds a bit like the polarity of some wires somewhere in the service were back to front.
Posted By: HCE727

Re: A must read post !! - 05/11/08 12:48 AM

After all of the excitement died down, with the fire co., we were waiting for PECO to come out. It hit me, when we first arrived at the house, we were not getting voltage. After we turned on the breaker next door, we had 120v. I told my helper to go next door and turn off the circuit that he turned on earlier. That was it! That circuit was traveling from one house to the next, traveling through the siding and capping. When I went next door to check it out, the wiring in the basement was a mess! I removed the circuit from the breaker, and put the service, next door, back together. I told the home owner what we found. I also told him the neighbor needed to get an an electrician, to find out what was causing this. After seeing the wiring in that basement, I didn't want any parts of that!
Posted By: HCE727

Re: A must read post !! - 05/11/08 12:57 AM

The next day I received a call from the electrician who was working on the problem (poor guy, his wife works with the HO, a freebie). He was there all day, ripping out wiring and jb's and putting it all back and still couldn't find the problem. He was going back the next day to try and find it. I told him to call me and let me know what he finds. The next day he calls me and tells me that he found it! It was all caused by an old window shaker AC, that was put in a couple of days ago. He unplugged the AC and there was no more voltage.
Posted By: Sixer

Re: A must read post !! - 05/11/08 03:23 AM

I posted here a couple of years ago about finding refridgerators on ungrounded systems having anywhere from 60 to 120 volts on the casing of the fridge. Once a ground was established, it solved the problem. Would the A/C causing your problem problem be doing something similar?
Posted By: renosteinke

Re: A must read post !! - 05/11/08 03:35 AM

It very well might have ... and for the same reason: compressor shorting to the case through the refrigerant. I suspect the "leakage current detector interrupters" that A/C's now come with would have tripped in this situation.
Posted By: sparkyinak

Re: A must read post !! - 05/11/08 03:59 AM

I just read all the posts and it occured to me check the neighbor's circuit entire length that tripped fron the breaker and the load. Power is some how is getting to ground and since it can not get back to the neighbors panel, it found it's way to the next house.
Posted By: EV607797

Re: A must read post !! - 05/11/08 04:41 AM

Pretty amazing. I love mind benders like this one. Let's keep them going. It keeps us all up to speed on the wacky things that are going on out there. Thanks for sharing this one Henry.
Posted By: harold endean

Re: A must read post !! - 05/12/08 01:01 AM

Sounds like stray voltage in the ground, that is showing up on metal pipes. I have seen it where the stray voltage came from the next door house. I have also seen where there was a pinhole opening in an underground primary service wire. There was 20-45 volts on all of the outdoor water faucets. Maybe you can get neighbors to shut down their service to see if the problem voltage goes away.
Posted By: harold endean

Re: A must read post !! - 05/12/08 01:03 AM

Oops,
I didn't read the last post. Glad everything turned out OK.
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