Residential Voltage Swings

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Tank11

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I'm experiencing an issue in a home where the electrical system in the house has begun to behave erratically. The lights throughout the house are dimming and flickering at random and when various appliances are run it causes circuit breakers to open in the main electrical panel. For example sometimes when the garbage disposal is run it causes the breaker feeding the TV to open. Also the lights dim and flicker more often when the washing machine is running.

I first checked with the local utility and they’ve metered the house and the service transformer and are 100% confident it’s not their issue. There are 3 or 4 other houses fed from the same transformer that aren’t experiencing any of the same issues. I also had an electrician shut off the main breaker to the house and check the incoming voltage at the house meter and it’s balanced when there’s no load on the house. The voltage varies from anywhere between 110 volts to 130 volts on either phase when any load is brought on (microwave, hair dryer, or washing machine).

I also had the electrician check the neutral to ground bond in the main meter cabinet and he also drove a new ground rod and neither of these fixed the problems. We then tried to isolate the circuit in question by running a hair dryer at different outlets in the house and we still see voltage swings each time.

Basically I’ve run out of solutions and am wondering if there’s anything anyone can think of that might be causing the problem. It started out of the blue about a year ago and the house is about 20 years old. The electrician thinks the whole house needs to be re-wired but I don’t want to get on board with that until I know what the exact problem is.
 
It really sounds like a bad neutral connection.

It is the only reason for voltage to rise if the power company supply is not rising.
 
Check the neutral connection. If the neutral has been compromised the may be a cause. If you actually lose the neutral it will cause big problems.
Remember that each of the 2 line conductors are 120v to neutral and 240v line to line. Should the neutral connection be partially compromised it will result is a unstable L-N voltage on each 120v and each 120v circuit. It may increase or decrease dependent upon the dynamics of the loads. Varify the neural at the SE and the POCO would need to varify that their service drop neutral hasn't been compromised.
You may check the L-L voltage and if it is stable but L-N voltages aren't suspect a neutral issue.
 
AL SE cable?

AL SE cable?

If you have an old aluminium SE service cable, the neutral (wires wrapped around the two hot conductors) may be corroding away.
You may have loose connections in the neutral. Check every where in the main circuit (even in the meter socket).
 
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Tank11 said:
The lights throughout the house are dimming and flickering at random and when various appliances are run it causes circuit breakers to open in the main electrical panel. For example sometimes when the garbage disposal is run it causes the breaker feeding the TV to open. Also the lights dim and flicker more often when the washing machine is running.

I first checked with the local utility and they’ve metered the house and the service transformer and are 100% confident it’s not their issue. There are 3 or 4 other houses fed from the same transformer that aren’t experiencing any of the same issues. I also had an electrician shut off the main breaker to the house and check the incoming voltage at the house meter and it’s balanced when there’s no load on the house. The voltage varies from anywhere between 110 volts to 130 volts on either phase when any load is brought on (microwave, hair dryer, or washing machine).


Basically I’ve run out of solutions and am wondering if there’s anything anyone can think of that might be causing the problem. It started out of the blue about a year ago and the house is about 20 years old. The electrician thinks the whole house needs to be re-wired but I don’t want to get on board with that until I know what the exact problem is.
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Normally with a bad neutral you will get more of a voltage swing than 110-130V.

A bad neutral doesn't explain the breakers tripping.

If I wanted to venture an educated guess I would say that you have a breaker or breakers that are burned out and arcing to the buss in the panel. Heat from one breaker can tansfer to others and cause them to trip.

Check the breakers and see if any of them feel hot when you are haveing problems to include the main. Or turn the main power off and check the breakers in question.

If what I'm thinking is correct you may need a panel change it all depends on the condition of the buss.

I would suggest that you get a different electrician to check things out.
 
growler said:
Normally with a bad neutral you will get more of a voltage swing than 110-130V.

A bad neutral doesn't explain the breakers tripping.

If I wanted to venture an educated guess I would say that you have a breaker or breakers that are burned out and arcing to the buss in the panel. Heat from one breaker can tansfer to others and cause them to trip.

Check the breakers and see if any of them feel hot when you are haveing problems to include the main. Or turn the main power off and check the breakers in question.

If what I'm thinking is correct you may need a panel change it all depends on the condition of the buss.

I would suggest that you get a different electrician to check things out.
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Bad breakers cannot raise the voltage. Could a bad neutral trip a breaker? I think it could.

But I do agree, get another electrician to check things out in person.
 
iwire said:
Bad breakers cannot raise the voltage. Could a bad neutral trip a breaker? I think it could.
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I agree that a bad breaker won't raise the voltage. I can measure say 127 volts on many services around here depending on the time of day and the load. Depending on the meter he is useing he could be off a little bit on measurements or the voltage could be 130V normally depending on where he is located.

Could a bad neutral cause a breaker to trip. Yes becasue the leg with the low voltage will draw more current for a motor load. He said that if the garbage disposal is running that it can cause the TV circuit to trip.

Iwire I do agree with you but I'm going more with experience than theory. I've seen some really bad neutrals and no breakers tripping. You know the type with voltage swings from 50V to 190s.

What I'm really saying is that I wouldn't jump on the bad neutral idea to the exclusion of other things that can be quickly checked.
 
Tank11 said:
I also had the electrician check the neutral to ground bond in the main meter cabinet and he also drove a new ground rod and neither of these fixed the problems.
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I not sure what they were hopeing to accomplish with another ground rod.

When I go on a service call like this I am sheptical of most all of the information given to me by the homeowner except for the symptoms and I even double check those.
 
[QUOTE-

I first checked with the local utility and they’ve metered the house and the service transformer and are 100% confident it’s not their issue. There are 3 or 4 other houses fed from the same transformer that aren’t experiencing any of the same issues.....[/QUOTE]



Those connections for the other houses are not your connections ai the Service Head and below .


On that note , how many times has POCO Denied Problem only to fix it later when recalled .


Don
 
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A landlord called to look at a unit f an 8 family were part of the lighting was out and glowed dimly part of the time. The unit we as feed from a main breaker located in the basement with the SE feeding the subpanel in the unit. What was happening was the one line was dead, when the thermostat call for heat from the 240v baseboard heaters, the heaters backfeed the dead line causing the load on that line to glow dimly.
One pole of the breaker had a bad contact which caused the open line. The breaker had to be replaced. But, as a temporary fix until a replacement breaker could be purchased knowing that the moving contact actually rubs against stationary contact when thhey aare losed I exercised it a number of times getting that contact to finally close.
So, it is possible to backfeed one dead line from the other live line through a connected load also.
 
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templdl said:
A landlord called to look at a unit f an 8 family were part of the lighting was out and glowed dimly part of the time. The unit we as feed from a main breaker located in the basement with the SE feeding the subpanel in the unit. What was happening was the one line was dead, when the thermostat call for heat from the 240v baseboard heaters, the heaters backfeed the dead line causing the load on that line to glow dimly.
One pole of the breaker had a bad contact which caused the open line. The breaker had to be replaced. But, as a temporary fix until a replacement breaker could be purchased knowing that the moving contact actually rubs against stationary contact when thhey aare losed I exercised it a number of times getting that contact to finally close.
So, it is possible to backfeed one dead line from the other live line through a connected load also.
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Agreed .



Don
 
Long and marginally sized run to the source could cause similar troubles as well.

In such situations if you put load on the neutral and you will more severely unbalance the voltage to the ungrounded conductors then you are used to seeing just because of voltage drop, this can easily be confused with open neutral troubles.

Not saying you have this problem, but don't dismiss it if you do have an unusually long run to the source.
 
I have run into this same scenario many times and it has always been one of three things
1-loose or corroded neutral connection(s)
2- burnt breakers and/or buss bars
3- POCO lying about having checked incoming voltage.
There was one panel (Murray if I remember right) that was used a lot in my area that only had an 8-32 screw bonding the neutral to the main buss. That 8-32 screw would cause all kinds of problems! Open up the main panel, including pulling the meter, and check all the connections. Do the same for any subpanels. Then pull off all the breakers in the main and any subpanels and look for burnt breakers and buss bars. If you don't find any smoking guns call the utility co. again and request a second inspection. I have completely disconnected the customer side of a service and metered the incoming voltage and it was all over the place, called PG&E and explained the problem, and they sent out a troubleman who said the problem is on the customer side. 2 hours and a few phone calls later a second troubleman comes out and within minutes repairs a corroded neutral splice in an in ground j box. My point is that sometimes the POCO rep is in a hurry, or just finishing their shift etc, and they really have nothing to lose by saying it's not their problem. Good luck- Scott
 
10fords said:
I have run into this same scenario many times and it has always been one of three things
1-loose or corroded neutral connection(s)
2- burnt breakers and/or buss bars
3- POCO lying about having checked incoming voltage.
There was one panel (Murray if I remember right) that was used a lot in my area that only had an 8-32 screw bonding the neutral to the main buss. That 8-32 screw would cause all kinds of problems! Open up the main panel, including pulling the meter, and check all the connections. Do the same for any subpanels. Then pull off all the breakers in the main and any subpanels and look for burnt breakers and buss bars. If you don't find any smoking guns call the utility co. again and request a second inspection. I have completely disconnected the customer side of a service and metered the incoming voltage and it was all over the place, called PG&E and explained the problem, and they sent out a troubleman who said the problem is on the customer side. 2 hours and a few phone calls later a second troubleman comes out and within minutes repairs a corroded neutral splice in an in ground j box. My point is that sometimes the POCO rep is in a hurry, or just finishing their shift etc, and they really have nothing to lose by saying it's not their problem. Good luck- Scott
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Don't waste time getting POCO out more then one time - place temporary high current loads as near as possible to meter or other items you can't access and check voltage conditions - verifying the problem is upstream in POCO equipment before even having them out the first time. If they don't think there is a problem repeat your testing in front of them and insist there is a problem and be prepared to explain why. If the tech they sent out doesn't understand hopefully he gets someone to come out that does.
 
If you turn all 2 pole breakers off in the panel and leaving the 1 pole breakers on would stop power transferring from the 2 pole breakers. Would help in reading incoming line voltages


Sent from my iPhone using Tapatalk
 
kwired said:
Don't waste time getting POCO out more then one time - place temporary high current loads as near as possible to meter or other items you can't access and check voltage conditions - verifying the problem is upstream in POCO equipment before even having them out the first time. If they don't think there is a problem repeat your testing in front of them and insist there is a problem and be prepared to explain why. If the tech they sent out doesn't understand hopefully he gets someone to come out that does.
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I guess it depends on the power company.

I had voltage issues at my own home, I called the power company on the way into work on a Saturday. Within a couple of hours they called me back, said they had been by the house, put in a load tester, confirmed the problem and had a repair truck on the way. By noon the issue had been fixed.

I have no doubt some power companies are as bad as described just saying don't assume they all are.
 
iwire said:
I guess it depends on the power company.

I had voltage issues at my own home, I called the power company on the way into work on a Saturday. Within a couple of hours they called me back, said they had been by the house, put in a load tester, confirmed the problem and had a repair truck on the way. By noon the issue had been fixed.

I have no doubt some power companies are as bad as described just saying don't assume they all are.
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I never said POCO was bad, I wanted to emphasize that you make sure you are confident the problem is on their side of things before even requesting they come look at it, then if their technician says otherwise you show him why you think it is POCO side problem. This especially true for those that post here stating it often takes a long time to even get a POCO representative out to look at a problem, then unless the problem is really obvious they don't put much effort into their troubleshooting. Also makes you appear to be a professional if you say it is a POCO problem and it is, then if you say that and they prove you wrong, or if you have POCO back multiple times and still can't figure out the problem.
 
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