ECN Forum Forums General Topics of the Trade General Discussion Area Loose neutral?

If you're getting an amperage reading, that means there is a load someplace that wasn't shut down... Might check that a pole of one of the disconnects isn't siezed/fused closed. If you meant volts, then that difference in potential between the metal equiptment casing and the ground rod, water pipe or whatever you're measuring to is a bonding issue. Chances are you have a bonding jumper/bonding screw, etc. missing or corroded. Your equiptment casing and bonding wouldn't typically be a PG&E issue, unless youre in equiptment that they supplied.

No, not nessesarily.... Although that, if an amperage? does seem a little high. The gorund there, as with all connected to that tranformer serving the area are grounding the POCO side, some less equally than others. But in the situation you describe, it could or would sound much more like what might be found with the lost neutral load on....

Rule of thumb for PG&E, voltage on thier side of metering OK, "NOT thier problem"....

I will throw this question out there, 'cause I know a number of people who don't break seals. Did you open the By-pass section of the metering? And inspect the neutral there? If any? Or the gutter above? (I'm sure many of us would have ripped the whole thing apart day-one.) What is that can to the far right? (It doesn't look like a regulation termination can for UG service, or is this OH service) Is ther any other service on, or in any of the 'other' buildings? Are there any other voltages, or transformers in the building?

Just for refferance is this 3-phase service?

Actually, yes day one I pulled the cover off the gutter and checked the connections there. That is where they connected the GEC to the neutral. The box to the far right is just a pull thru for underground feed. There are no transformers in the building. The one transformer that feeds this building feeds two others as best I can tell. Yes, it is a 3-phase service with no high leg. Tomorrow I'm going to shut off both mains and see if there is any voltage neutral to ground. If there isn't I'm going to take Lostazhell's advice and ring out the neutral and feed wires. If I'm still getting voltage I'm just going to tell the owner to call someone else.

Many thanks

Byron,
Why lumber someone else with this problem?.
You are Johhny on the spot, you should be able to work this out for yourself.
As far as the Owners comments about "this has been going on for about a year" go, I think it is just rubbish, no way would an installation in my opinion sustain a fault like this over a period of time, without some sort of burning occuring.
As has been mentioned in the Chat rooms here, look to get the place shut off during the weekend, there is no such thing as "Can't turn the power off!".
You need to systematically track and and trace all of the neutral conductors, to make sure that there is nothing amiss.
Get an extra guy if you have to.
A lot of my time is taken up with investigating fires of Electrical origin.
If this place goes up, you could be looking at man-slaughter charges through in-action.
Just bear that in mind.
Just my $0.02 worth.

If tomorrow, you have ALL MOCP's (Main CB's) OFF, and you have voltage, then the fault current is from before the mains. If this is the case, it is even more dangerous!! A cause of this may be an arching phase to ground or neutral. Something like that could have created all the other problems. Locating it live will expose you to an arch blast hazard - quite likely - will be the moment of discovery. At that time, if there is voltage with ALL MCOP's OFF, I would get PG&E back out to kill the service before it kills you or anyone else. I wouldn't go looking for it without proper protective gear, for that matter I wouldnt still, unless the service was dead, completely dead. A PG&E short goes off like a grenade - NOT FUN! Trust me....

If you have no voltage, tear that baby apart, and make like you were putting the whole thing back together fresh! (Might as well, what ever it is may require replacemment of some or all of the gear.) After the neutral ground connection is found in or past the sub-panels, check out what ever it is, because it may have been carrying a lot of current, for what sounds like a long time. But the key to the voltage problem is that neutral connection, no point in turning it back on otherwise. Sometimes not too easy to find, but its there.... Sometimes it can be tricky, as often it will even show the correct voltage, but be unable to carry a load at all, or even to varying degree. Then all of the grounding and bonding repairs....

[This message has been edited by e57 (edited 06-27-2006).]

Problems solved.
I shut down all the sub panels. When I shut down a sub panel on the right meter's load I noticed the sizzle between the left meter case and the sub panel to it's left stopped. I verified this via case to case voltage test. I found the one phase that was causing problems by systematically removing them one at a time and checking the case to case voltage. It turns out that the inside sub panel has an AC on the roof. They only fed the AC panel with two #6 wires and used the conduit as a ground. The real problem arose when some handyman electrician saw he could fit another breaker in that panel and used it for security lighting. Thus the neutral for the 120V lighting circuit was tied into the casing. This caused the voltage through the ground. What is interesting is how that voltage got back to the transformer. It must have found a path through the other meter's conduit system that was better than it's own. I wouldn't have suspected a problem that is on one meter to show symptoms on another meter that is tied together through a hot gutter.
As far as the voltage spikes, that was another problem all together. Someone tied the "neutral" to a metal box where they pulled in a multi wire circuit. They took the neutral and wire nutted it to the neutral for the other leg and pushed them back. They thought they would gain a "neutral" for the receptical by connecting to the box.

Many thanks for your help everyone!

Byron

Whoa, might not be out of the woods yet, need to be thourough, thats 3 neutral to ground connections that could explain current on the ground, but NOT the HIGHER, or LOWER voltages.

When you have a 120/208, or for that matter any system other than just plain vanilia 120, and you get a higher voltage to ground than what is input to it, that voltage, that higher voltage has to come from somewhere. In a high/low voltage scenaio, Phase A and Phase B (Or C) can borrow and steal from each other... One goes up, 1-2 two down, et cetera. The "real" neutral point can "float" between loads. Depending solely on which might have more load than the other at the time. A set of voltages read fluctuating like 140, 100, 90 would mean the balance point of the load is not held in check at one point by solid grounding. Was this High/Low problem on one of the circuits you just described and limited to them or it alone? If this High/Low problem was panel wide, or service wide, it sounds like there is still a problem.....