Voltage on the Roof???

[domnic]

hot roof

hot roof

A grounded conductor that is open.

 

[ceb58]

Only load or breaker on was the pool pump motor. I didn't turn it off but did have someone turn the feeder breaker off, which stopped the voltage.

Just to be clear, I wasn't called there to check why there was voltage on the roof. I was there doing other work and the painters came to me asking why the roof was shocking them. So I only got to check enough to do/find what I described here.

[/QUOTE]

I understand that that is not why you were there but............ Any way. You may need to check to see if the feeder breaker is not double tapped. It could feed the pool panel and something else under or connected to the roof.

 

[Little Bill]

UPDATE

UPDATE

Ok, I went back to the "problem" house today. Didn't have to but it was bugging me.
What I am about to say doesn't really convince me that I fixed anything but here goes.

I first took the jumper loose from the EGC bar in the subpanel but left it clipped to the metal roof
Still had voltage but only about 85V. I figure between a loose connection on the alligator clip and the length of the jumper is why it was lower than 120V

This time instead of turning the feeder breaker off I just turned off the pool pump motor.
The voltage remained

I noticed that the breaker directly under the pump motor breaker didn't look all the way off so I checked and it had voltage. When I (quickly) looked yesterday it appeared off. But since I had time today I checked it more closely. The breaker is a GFCI so I hit the test button and no trip. So I turned it off, which was hard to do as I think it had corrosion inside. Anyway, when I turned it off the voltage went away. I turned it back on to verify and the voltage returned. I again tried to use the test button but it didn't work. But I did notice it had a "buzzing" sound when I pushed the test button.

This breaker is for a pump that cleans the pool, like a vacuum. I disconnected the conductors and removed the breaker. I'm trying to figure out what or how this circuit could energize the roof. Only thing I see is the plumbing from the pump goes underground but it is PVC. But there is a gas line that is about 5' from it that goes underground. There is a gas stove on the top floor and the vent shown in the pictures is where that stove is. Thinking maybe the voltage got on the gas line and traveled up to the stove & up the vent.

Other thing I saw was the (normal silly) grounding done by phone/cable where they just drove a ground rod and tied their grounds to that. There is some phone/cable lines that run upstairs. But there is no service at the house as the HO doesn't need it because it's just a weekend/vacation home.

So, let's hear your thought on whether I found the fault or just a fluke that the voltage went away. Oh, and I did check line to ground & line to neutral on the feeder and it checked good. I may have left something out so ask if you have a question.

Side note... There were (3) GFCI breakers in the panel, one for pool pump, one for cleaner pump, and one for a receptacle. NONE of the GFCI breakers would work using the test button.

 

[Stebs]

Just thinking out loud... All pool equipment should be bonded together and bonded to the pool shell as well. Is it possible that you have a fault in the cleaner pump that is passing voltage to the bonding wire, which is possibly getting passed to the gas line via the heater. I would think the grounding of heater and gas appliances and gas pipe would have taken care of the issue though.

 

[dmxtothemax]

Ok, I went back to the "problem" house today. Didn't have to but it was bugging me.
What I am about to say doesn't really convince me that I fixed anything but here goes.


NONE of the GFCI breakers would work using the test button.

The first statement troubles me greatly

The second one even more so !

The home owner might think you have corrected the problem

when you haven't

I would advise the home owner to get a Master electrician to check it ?

 

[rippledipple]

hot roof

hot roof

The first statement troubles me greatly

The second one even more so !

The home owner might think you have corrected the problem

when you haven't

I would advise the home owner to get a Master electrician to check it ?

by any chance does his house have alum. siding??

 

[Saturn_Europa]

I always start with what I know is bad. In your case I would replace the gfci breakers and go from there.

 

[Little Bill]

The first statement troubles me greatly

The second one even more so !

The home owner might think you have corrected the problem

when you haven't

I would advise the home owner to get a Master electrician to check it ?

I'm sorry you're troubled so but perhaps I didn't convey info enough in previous post.

First , I am working on another project at this house and was ask to look into this by the HO after telling them about the painters. I didn't have anything to do at the house yesterday but knew the painters would be there. So I went back to check it better since I only spent a little time on it the first time. It was "bugging me" to the point that I wanted to check it closer and make sure the painters were safe.

The voltage went away after I disconnected/turned off the cleaner pump but since all three GFCIs were bad I'm not sure if that was the only problem. I am going to replace the GFCIs but didn't have any with me and the house is an hour away.

I'm not sure what path there is to the roof so that's another "unknown" to me.

No one lives at the house and no one will be for a while. I told no one that the problem was fixed. When I go back and install the new GFCIs maybe that will reveal something.

I am an electrician, thank you! I am working for a GC on the house but when this problem arose the owners asked me to check it out and repair anything I find.

 

[mgookin]

It sounds like you're narrowing it down.
Like you said, replace what you know is bad (breakers) then continue on until the culprit is found.
I like your theory about the gas line. If you check continuity from that to ground I'd bet it's open.
That leaves the question of how is the voltage getting on it from that branch circuit, which is of particular concern with a pool involved.

 

[Little Bill]

It sounds like you're narrowing it down.
Like you said, replace what you know is bad (breakers) then continue on until the culprit is found.
I like your theory about the gas line. If you check continuity from that to ground I'd bet it's open.
That leaves the question of how is the voltage getting on it from that branch circuit, which is of particular concern with a pool involved.

I didn't want to bring the pool into this discussion so as to not cloud the issue. Especially since I have a pool bonding thread about a different house.

But I was concerned with this house since a pool was involved so I checked the bonding around and to the pool. I have continuity between the ladder and handrails so I know there is some bonding around the pool.
However I can't find the wire back to the pool equipment nor is there a bond to the pool pump motor. There is a short piece of bare #8 attached to the cleaner pump but it isn't connected to anything.

I am going to address the bonding after I replace the GFCIs.

 

[rippledipple]

hot roof

hot roof

I was working at a house and one of the painters said he was getting shocked off the roof. It was a metal roof and hot outside. So I thought he must have just thought he got shocked. Then another one came to me and said he also got shocked. So I went to check it out.

The part of the house where they reported the shock is an addition that was added some time ago and has a separate service. There is a single meter but dual feeds to the house & addition. The meter is on the pole about 20'-30' from the addition.

So I put a lead on the GEC or the conductor that grounds the service at the transformer. I then went up the ladder and checked the edge of the roof. Sure enough there was 120V on the roof.
Now the only thing on in the addition was a feeder breaker to a subpanel for the pool equipment. I had someone turn the feeder breaker off and checked the voltage again and it was gone. Now the only load on the subpanel was the pool pump motor.

Since I was there to do other work I didn't spend a lot of time searching for the problem. But what I did do was run a bare #8 from the EGC bar in the subpanel to the metal roof. I put an alligator clip on the end up on the roof. I had the painter clip it on the metal for me. When he touched the metal it sparked a good bit but I told him to go ahead and clip it on.
I checked the voltage again after connecting the jumper and the voltage went away. Painter was brave enough to touch the roof with his bare hand and said he didn't feel anything.

Now I know I didn't fix anything, just made it so they didn't get shocked. The HO wants me to check this out in full when I can so I thought I would share it here to get some ideas.

What I don't understand is why the subpanel or pool pump would cause voltage up on the roof. I didn't find any of the equipment with voltage, just the roof. Since nothing in the subpanel has anything to do with inside the building I'm not seeing how the roof got energized. Especially since no loads in the house were on.
Any ideas what would cause this and how to track it down?

Little Bill,I'm curious to find out what happen to the hot roof problem???