Good one from yesterday

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ceb58

Senior Member
Location
Raeford, NC
This will be a little long but bear with me:grin: Service change on church upping from 100amp to 200amp. Poco supposed to arrive at 8:00am to cut overhead loose they show up at 10:00:mad:. Get every thing tore off and new meter combo with overhead installed, new panel inside. There were two A/C units feed from old panel on out side, I was able to reuse the 2'' cond. and LB. While my son was mounting the indoor panel I was going to hook the A/C units back into new combo. While twisting the grounded conductor on the se cable I touched the can, felt a tingle ??? I did it again and got a nice bite from it. Break out meter 28v from grounding conductor to GEC ??????? Power is off the service conductors and the service drop are cut. Start looking. At some point in time they joined the fellowship hall to the church building which had its own service. So now we really have one structure with two services. OH crap some one is back feeding something. Turn main off in fellowship hall still have voltage. Every thing feeding this building is overhead ??????? Its now 1:00pm and the inspector shows up, OH crap no where close to being through. I tell him look I have ran into something and cannot find the problem. He is a former EC and a nice fellow, " no problem you my last inspection for the day lets find the stray voltage" Tell him what I have done so far. Try unhooking the neutral in fellowship hall. Did that, still voltage. We tried several thing he came up with, still voltage. Inspector is setting in a chair under a tree while sweat is dripping off my head and other places, I go over to talk to him to see if we can come up with other ideas. Behind him is a poco pole that the service drop is on and three feet away is a concrete filled pipe in the ground to protect the pole I said let me try something. Put meter on ground wire on the ploe scratch the paint on the pipe and damn 32volts. Its the ground rods picking up stray voltage. Inspector says you need to call poco THEY have a problem. He is correct THEY have a problem. I ask him what about this inspection, Fri. is a holiday for you, we are not through because of this and I need power back on today. He says, I have inspected your work before with no problems, you have worked your butt off trying to find a problem most would ignore, every thing you have done so far looks good. He fills out the sticker puts it on the can and says have a good 4Th. Poco shows up to reconnect, I show service guy what we have, he gets on phone and starts writing down transformer numbers and pole numbers for them to schedule an engineer to come and find where this voltage is coming from. He hooks up the service drop and the stray voltage went away from the can but its still on the poco ground on the pole. The moral of the story is #1 the poco stuff is not always right and #2 not all inspectors are jerks
 

iwire

Moderator
Staff member
Location
Massachusetts
I am not sure there is any trouble at all.

In a nutshell you found voltage between the incoming POCO neutral and the GEC for the building?

Is that correct?
 

220/221

Senior Member
Location
AZ
In a nutshell you found voltage between the incoming POCO neutral and the GEC for the building?

POCO neutral was cut loose.

Power from GEC to the can (which I assume was bonded to the metal piping???)


and #3 not all stories are short.

The story was short enough but that was one long paragraph.
 

Twoskinsoneman

Senior Member
Location
West Virginia, USA NEC: 2020
Occupation
Facility Senior Electrician
not all inspectors are jerks

Great guy. I think a lot more inspectors are like this guy than the jerks.

I am not sure there is any trouble at all.

In a nutshell you found voltage between the incoming POCO neutral and the GEC for the building?

Is that correct?

Are you implying that this is acceptable neutral to ground voltage?
Sorry If I'm missing the point...
 

iwire

Moderator
Staff member
Location
Massachusetts
Are you implying that this is acceptable neutral to ground voltage?

I am saying it is to be expected if the GEC at the home as connected to a metal underground water piping system that is common to the neighbors metal water pipe.

Under those conditions the water line is basically a parallel neutral and for reasons of voltage drop or connections with some impedance a certain amount of potential between the EGC and the neutral are to be expected.

Under normal conditions when everything is connected properly the metal water piping will be carrying a fairly large percentage of the unbalanced neutral current.
 

Twoskinsoneman

Senior Member
Location
West Virginia, USA NEC: 2020
Occupation
Facility Senior Electrician
I am saying it is to be expected if the GEC at the home as connected to a metal underground water piping system that is common to the neighbors metal water pipe.

Under those conditions the water line is basically a parallel neutral and for reasons of voltage drop or connections with some impedance a certain amount of potential between the EGC and the neutral are to be expected.

Under normal conditions when everything is connected properly the metal water piping will be carrying a fairly large percentage of the unbalanced neutral current.

True enough. Would you expect the voltage to be gone when the service was turned on??
 

ceb58

Senior Member
Location
Raeford, NC
I am not sure there is any trouble at all.

In a nutshell you found voltage between the incoming POCO neutral and the GEC for the building?

Is that correct?

No, where I found the voltage was between the ground wire on poco pole and a steel pipe in the ground that protected the pole. That voltage was traveling through the earth to the ground rods at the service ( about 20' away). The only thing I can think of why I was getting a shock and reading voltage between the GEC and the grounding conductor for the A/C unit was the A/C unit was sitting on a metal pan directly on the earth and was far enough away to not pick up the stray voltage.

POCO neutral was cut loose.

Power from GEC to the can (which I assume was bonded to the metal piping???)




The story was short enough but that was one long paragraph.

There was no bond to water pipes. Church had recently changed from a well to county water. The church had been re-plumbed all in pex piping and any and all metal piping had been removed.
This is one thing I was looking for while crawling under the building looking to see if some one had spliced into the A/C feeders or if there was some other problem with the feeder.

At least I used spell check:grin:
 

Jim W in Tampa

Senior Member
Location
Tampa Florida
poco might have bad neutral. Or you simply missed something. Seems strange that the balard would show anything if that close to pole.

As for the inspector yes a few actually understand the work side. I have had a house passed in morning that would not been ready till end of the day. He was signing off the finished one next door and i asked him to take fast look at one next door. Same identical house and he knowed my work. He just looked at me and asked if i was wiring it like the other one. Where is the permit and be sure you finish today. Trust is key word.
Yes you owe him a case of what ever but he will not take it. They could loose job fast. Have seen them thirsty and told them help themself but they wont.
 

Jim W in Tampa

Senior Member
Location
Tampa Florida
Jim I know you are a good electrician... but an inspector that passes work without looking at it is worse than the one that makes up his own rules
Not really, when they see the same house by same guy over and over they know what you will turn out. You don't really think inspectors have time to look at every detail do you ? Knowing the electrician means a lot. I never tried to get away with anything simply because it is just as easy to do it right. What they watch is the places wired by green help that often are left to wire alone after 6 months. They are the ones that make mistakes and there boss will not even see the job. Inspectors can notice in 2 minutes if they really need to spent extra time looking. They spend as much time as needed when they start seeing slop.
 
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