Pulsing Lights

[prattz99]

Hi,

I looked at a job today and the homeowner is telling me the washing machine will pulsate the lights throughout the whole house when it is running. It is a single family dwelling built in 1996, all original wiring, home run for the washing machine, underground aluminum service feeders, meter pan is over 100 feet from the 200 amp panel. The lights look dim but not terribly dim, and will brighten when the electric kettle, or refrigerator is on. I told her I think there is an issue with the neutral as the 220v appliances don't seem to trigger the pulsing or increase the brightness of the recessed lights.

What do you guys think? What do you suggest I look for or where to start troubleshooting? I opened up the main panel box and looked for obvious signs for a lose connection. I did not take any voltage readings or have my thermal imaging camera. Everything felt fine to the touch.

 

[xformer]

What type and style of lights?

 

[LarryFine]

I told her I think there is an issue with the neutral as the 220v appliances don't seem to trigger the pulsing or increase the brightness of the recessed lights.

This. Only a compromised neutral-current pathway can cause loading to increase voltage, and it will increase on one line while decreasing on the other line.

A pair of small incandescent bulbs side-by-side, wired as a 120/240v 3-wire load, can provide a very telling simultaneous visual indication of relative voltages.

What do you guys think? What do you suggest I look for or where to start troubleshooting?

I suggest measuring for voltage between the panel's neutral and known ground, like metal water pipe, the meter base (unless the issue is on the line side of the meter), etc.

A long piece of almost any kind of wire will allow you to measure between distant points. Perhaps as far as the house of a neighbor who is not experiencing similar symptoms.

 

[Dsg319]

Hi,

I looked at a job today and the homeowner is telling me the washing machine will pulsate the lights throughout the whole house when it is running. It is a single family dwelling built in 1996, all original wiring, home run for the washing machine, underground aluminum service feeders, meter pan is over 100 feet from the 200 amp panel. The lights look dim but not terribly dim, and will brighten when the electric kettle, or refrigerator is on. I told her I think there is an issue with the neutral as the 220v appliances don't seem to trigger the pulsing or increase the brightness of the recessed lights.

What do you guys think? What do you suggest I look for or where to start troubleshooting? I opened up the main panel box and looked for obvious signs for a lose connection. I did not take any voltage readings or have my thermal imaging camera. Everything felt fine to the touch.

Need to check the service/feeder neutral. Could be open.

 

[prattz99]

What type and style of lights?

Incandescent lighting mostly.

 

[prattz99]

This. Only a compromised neutral-current pathway can cause loading to increase voltage, and it will increase on one line while decreasing on the other line.

A pair of small incandescent bulbs side-by-side, wired as a 120/240v 3-wire load, can provide a very telling simultaneous visual indication of relative voltages.


I suggest measuring for voltage between the panel's neutral and known ground, like metal water pipe, the meter base (unless the issue is on the line side of the meter), etc.

A long piece of almost any kind of wire will allow you to measure between distant points. Perhaps as far as the house of a neighbor who is not experiencing similar symptoms.

Great, thank you! I'll have the utility come out first and check the connections at the pole. Then if it's still acting up I'll check the meter pan, and the main panel. If everything checks out would it be same to assume the underground wiring is compromised? Aluminum underground service conductors are only good for is it 20 years?

 

[hillbilly1]

Great, thank you! I'll have the utility come out first and check the connections at the pole. Then if it's still acting up I'll check the meter pan, and the main panel. If everything checks out would it be same to assume the underground wiring is compromised? Aluminum underground service conductors are only good for is it 20 years?

Georgia Power has a lot a neutral failures on their first underground installations, can’t remember if it was poor quality wire, or bad installation practices.

 

[LarryFine]

Great, thank you! I'll have the utility come out first and check the connections at the pole. Then if it's still acting up I'll check the meter pan, and the main panel. If everything checks out would it be same to assume the underground wiring is compromised? Aluminum underground service conductors are only good for is it 20 years?

As far as the utility is concerned, you don't care about the pole connections, only at the meter.

They're responsible for everything up to the meter. Don't do their troubleshooting for them.

 

[Hv&Lv]

Georgia Power has a lot a neutral failures on their first underground installations, can’t remember if it was poor quality wire, or bad installation practices.

Generally speaking, bad installation practices.
We install everything in pipe now and have for the last 25 years.
It really cut down on our bad UG problems.
We still have some UG wire doing well from the 70s, so I know most wires are good.
Years ago we had certain contractors installing services for us. We had a rash of bad UG secondary services..
they weren’t removing the staple from the reel and dragging the wire across the face of the reel damaging the wire.
we figured this out because the bad spots were about 5-8’ apart, sometimes as many as 6-8 bad places in a service.

 

[Hv&Lv]

Great, thank you! I'll have the utility come out first and check the connections at the pole.

What, you can’t check your side first??

 

[hillbilly1]

What, you can’t check your side first??

Last year I had flickering lights, I went through everything to make sure it wasn’t on my side (it would have been embarrassing if they determined it was, LOL). Before I could call them, my wife said there was a red light on at the poco transformer early in the morning. Hmm, there’s no light on the transformer. It was a glowing connection on one of the hots. The poco came out, tightened the connection. All was fine for another week or two, it started again. Poco came back and replaced the hardware on the lug this time. Haven’t had a problem since.

 

[prattz99]

What, you can’t check your side first??

If it was my house I would. But I wouldn't want to charge someone for my time only to find out it was out on the street.

 

[Hv&Lv]

If it was my house I would. But I wouldn't want to charge someone for my time only to find out it was out on the street.

So what if the POCO comes out and finds it on your side?

 

[LarryFine]

So what if the POCO comes out and finds it on your side?

Ours doesn't charge. I ask enough questions to decide whether to suggest calling them before paying me.

If it sounds like an open neutral, I tell them to turn off the power, and to tell the POCO that an electrician said it's a bad neutral, and causing damage.

The advantage to them is that it's free; the disadvantage is their wait time.

 

[Hv&Lv]

Ours doesn't charge. I ask enough questions to decide whether to suggest calling them before paying me.

If it sounds like an open neutral, I tell them to turn off the power, and to tell the POCO that an electrician said it's a bad neutral, and causing damage.

The advantage to them is that it's free; the disadvantage is their wait time.

We dont charge either.

And don’t mind going if the electrician has done his work, such as asking the right questions or checking his side. Some won’t even open a panel.

I can’t tell you how many times I have been to houses where the electrician says he checked everything and call the poco
My guys get there and can’t find anything.
Back and forth…
I go determined to find something and generally find something loose in the Meterbase or main panel.
Last time was a loose screw on the #4 copper bar from one side of the main panel to the other
Electrician had been there twice already..

Then he got upset when I suggested to the HO to demand their money back because he didn’t do his job.
He told me that was a factory connection and he don’t check those…