Latest Discussions : Electrical & Lighting

mrtomwj

04:33AM | 09/26/06
Member Since: 09/25/06
4 lifetime posts
I had a BGE (local power company) service person come out to investigate what I believe to be an open/loose neutral problem. The service person did not believe there to be a problem. (and didn't even seem to understand that power traveled in a loop and needs a return path) When a clamp-on amp meter is applied to each of the main loads in my panel, amps are seen coming in as there should be (~15A on one, ~5 on the other at the time of the test) When the meter is applied to the neutral, zero amps are shown returning through the service neutral (not even a fraction of an amp, totally zero). When the meter is applied to the house grounding (connected to pipes) anywhere from 5-10 amps are flowing through the ground. This seems to point to no current returning through the service neutral and all flowing through the grounding line. The service tech only checked voltage between the hots and neutral in the meter box and the main panel (which I think since the neutral is bonded to the grounding in the panel, it would just flow back through the grounding and give a false positive) No check was done at the transformer or with the neutral isolated from the grounding while the system was powered down. My father used to be an electrician and said that it doesn't sound right for all of the current to be returning through the ground and nothing through the service neutral, so I wanted to get the opinion of a currently licensed electrician before I contact bge again about it.

Billhart

06:36AM | 09/26/06
Member Since: 04/25/05
1915 lifetime posts
Did you put a clamp on ampmeter on the Ground Electrode System wiring?

What was the voltage when measured from neutral to the each hot? How close where they?

Something does not add up here. The earth if not that good of a conductor and will give poor results when it is used as a ground return.

For example you can use a single ground rod as the ground electrode system if it measures less than 25 ohm. Otherwise you need a secondary electrode. But it does not have to be measured. Since specialized equipment is required so typically two ground electrodes are used and it is never measured.

Now local soil conditions will have a lot to do with the resistance of the ground electrode system.

And in a case like mine where a it is connected to the metalic water line and connects to the metal main that parallels and is very close to the power pole ground rods the ground is probably a fairly good return path.

What was the reason that you called the power company in the first place.

And the next time try to get more of an imbalance. Use toasters, hair dryer, space heater, electric skillet, etc. Just make sure that they are all on the same leg.


mrtomwj

06:49AM | 09/26/06
Member Since: 09/25/06
4 lifetime posts
The initial cause for my concern was when I was doing plumbing work (not realizing the system was grounded through it) and took out a main section of pipe, some lights in the house dimmed and some got brighter, and a few electronic devices got ruined. I figured if the service neutral were working properly, this should not have happened.

mrtomwj

06:58AM | 09/26/06
Member Since: 09/25/06
4 lifetime posts
I clamped the amp meter on both hot lines coming into the panel from the meter, as well as the neutral line coming from the meter. I then also put it on the ground wire that connects down to the plumbing (which I believe the city plumbing does travel right next to the power pole where the transformer grounds) The service neutral had absolutely zero amps on it, and the ground wire to the plumbing appeared to be carrying all of the return load that wasn't balanced on the hots.

Billhart

07:32AM | 09/26/06
Member Since: 04/25/05
1915 lifetime posts
Yes, you have an open or high resistance neutral.

The "problem" is that the in, your case, the ground return is able to carry the load.

You need to get them back out.

Ask them to remove the ground connection while power is on.

Either they will refuse and find the real problem. Or he will do it. That will solve your problem when OHSA comes to investigage the dead body.

If you get any problems with getting them back out then ask for a suppervisor in the engineering department.

If that does not work then contact the state regulatory commission (Public Unitities Commission, Corpoartion Commission, etc).


mrtomwj

05:45AM | 09/28/06
Member Since: 09/25/06
4 lifetime posts
They came back out yesterday and finally pinpointed to problem to the underground neutral feeding to my meter. There was a break in the line underground that was an 8" section that was corroded/fried...basically looked like white powder and toothpasted :-P So they cut out all the corrosion and put a splice in and all is good now. Thanks for the help!


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