OT Weird Electrical Problem

johndeere720GA · Feb 3, 2013

A friend of mine called me up the other night asking if I could take a look at his electrical problem. When I arrived they had a light on in the living room but it was very dim. He then showed me the light in the refrigerator and it was like looking into the sun. I unplugged the refrigerator and checked the votage at the outlet with a DVM and got ~170 volts. I then checked the power at the light and it was down to ~70 volts. So it appears that the 240 total is not being delivered properly to each leg of the bus. The power company came out and did not speak to anyone but they did recrimp the service to the house. There are at least 3 houses on the transformer but I am not sure if anyone else is experiencing any issues maybe its a bad transformer.
I am guessing that it is a problem with the neutral on a circuit. If that is the case how do we determine the bad circuit.
A little about the house it is older built in the 40"s service wiring is aluminum but all of the branch circuits are copper. The house is also using a common bus for ground and neutral and does not have a seperate ground. He did install a new clamp on the ground rod. Should we drive a new ground rod?

Thanks in advance for all you time, consideration and hopefully suggestions with this problem.

Janicholson · Feb 3, 2013

Definitely a neutral issue, probably not ground issue. Use a volt meter and check the three incoming wires at the top of the service panel. Across the outside 2 terminals it should be 220 to 235 volts.
From left to center terminals it must read 115 to 120. from right to center it must be within a volt of the same reading if not exactly the same.
If it is good at that point touching the terminal metal, try touching the any single breaker to the neutral bus all should be 120 (or as found above)
The issue will produce heat. A thermal (hand held) infrared thermometer will find it.
If it checks bad on the incoming terminals check the wires where exposed above the terminals. If good there, the center terminal (Neutral) is corroded. Calling an electrician, or pulling the pole disconnect or meter from its socket is needed before messing with the live connections. Call the service provider !! Jim

John B. · Feb 3, 2013

I would throw the main breaker or disconnect then check all the mains that are coming in and see what voltage each leg has.
This would tell you if you have a bad transformer.

JMOR · Feb 3, 2013

(quoted from post at 14:14:38 02/03/13) A friend of mine called me up the other night asking if I could take a look at his electrical problem. When I arrived they had a light on in the living room but it was very dim. He then showed me the light in the refrigerator and it was like looking into the sun. I unplugged the refrigerator and checked the votage at the outlet with a DVM and got ~170 volts. I then checked the power at the light and it was down to ~70 volts. So it appears that the 240 total is not being delivered properly to each leg of the bus. The power company came out and did not speak to anyone but they did recrimp the service to the house. There are at least 3 houses on the transformer but I am not sure if anyone else is experiencing any issues maybe its a bad transformer.
I am guessing that it is a problem with the neutral on a circuit. If that is the case how do we determine the bad circuit.
A little about the house it is older built in the 40"s service wiring is aluminum but all of the branch circuits are copper. The house is also using a common bus for ground and neutral and does not have a seperate ground. He did install a new clamp on the ground rod. Should we drive a new ground rod?

Thanks in advance for all you time, consideration and hopefully suggestions with this problem.

significant piece of information is, are voltages back to normal AFTER the power company visit?

johndeere720GA · Feb 3, 2013

I have not been back to check but he did say the lights have dimmed on a couple of occasions since the power company was there. Oh yea that is someting i forgot to mention, the trouble is intermittent.

Janicholson · Feb 3, 2013

With respect. If the issue is at a local multi-user transformer, checking like that would work. If it is in the service to that specific house only, it would prevent the unequal (non balanced) load at the house, and might appear to be normal. I think it must be checked under load. Jim

Walt Davies · Feb 3, 2013

Bad connection at the white neutral wire if the power company says their system is OK then it's his fault check all neutral connections starting at the grounding rod. Move connections to see where the break is.
Walt

johndeere720diesel · Feb 3, 2013

I've had a similar issue it was a overhead service line connection on my pole fixed that all has been good since. Also last year had to change meter socket as one leg was left loose and burned the lug off that caused same issue but was more a half power issue then lights dim and some bright

js305 · Feb 3, 2013

Had similar problems in the 35 years I have lived out from the city. One time it was a corroded lug on my main breaker. One time the transformer out on the road was the culprit. That's the one that was giving us a high voltage on one leg.

The best one was when my neighbor called me in the middle of the night, wanting me to help him with his well not working. I go down there and while standing in his well house I ask him where the disconnect is. He leaves and in a little bit the light goes of in the well house. I stick a screwdriver across the start cap and find the power is still very much on. One leg of the 220 was wired through a breaker in his house and the other was coming directly off the transformer on the road, no breaker, cutoff, not even going through the meter.

Never assume anything......period.

dr sportster · Feb 3, 2013

Here is what I would do find the three wire that is feeding that circuit in the panel . Trace it to the first box it branches out into the circuit and tighten the wire nut on the neutral. I thought I swore off these electrical questions but I guess not.Common bus for neutral and ground in the main panel is supposed to be like that.Find the circuit by flipping breakers.

evilboweivel · Feb 3, 2013

When that happened at my first house power company came out and everything looked good.
I said wait a minute, went inside and turned a iron on.
Voltage dropped on one leg
They ended up moving the nuetral to a different lug on the meter base. The original one was loose and pitted

johndeere720diesel · Feb 3, 2013

I've had a similar issue it was a overhead service line connection on my pole fixed that all has been good since. Also last year had to change meter socket as one leg was left loose and burned the lug off that caused same issue but was more a half power issue then lights dim and some bright

MarkB_MI · Feb 3, 2013

Like Jim says: Bad neutral. Get it fixed ASAP!

Dick2 · Feb 3, 2013

It could also be a break or bad connection in one side of the line; that will cause the voltage that you have described. That happened to the neighbor; it burned out some appliances on the high side of the line and some appliance motors on the broken side burned out from trying to start on low voltage.

It turned out that one side of the AL burial service wire had burned out underground. Power company paid for the damage, as it was their problem.

W_B · Feb 4, 2013

(quoted from post at 21:09:59 02/03/13) Like Jim says: Bad neutral. Get it fixed ASAP!

Yep, had this same problem about a year ago. Luckily it was an easy fix, had a corroded neutral connection in the box on the pole just below the meter. My guys put in a new connector and all is right with the world. Cost me two control panels on the stove (at about $120 ea.), burnt finger and thumb installing the last one (don't ask) and several light bulbs before we figured it out. The power company would only check that the incoming voltage to the meter was correct, wouldn't touch anything beyond that.

johndeere720GA · Feb 4, 2013

Thanks for all of the replies. The power company cam back out and replaced a neutral line somewhere according to my friend. Everything seems to be working and stable at this time.

OT Weird Electrical Problem

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JMOR

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Janicholson

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