All lights flickering

[sparky1118]

Good morning everyone. I have a customer who has an issue with all the lights in the house flickering on a dimmer. I figured a neutral issue. So I tightened all the neutrals in the panel also checked the neutral at the meter socket. Everything seemed good. I called the power company and had them redo the terminations in the hand hole. Still nothing is working. This house is about 20 years old and they have never had this issue before they have both LED and incandescent fixtures that are doing the same thing. Any thoughts for what I may check next?


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[petersonra]

Have you checked for ghosts?

 

[Strathead]

First, change the dimmer to a light switch. Most likely scenario in my mind is an incompatible or defective dimmer. Otherwise, your description is vague. Is this one circuit, one dimmer? Are there dimmers with only incand on them? Do the lights all flicker in unison or differently?

 

[sparky1118]

First, change the dimmer to a light switch. Most likely scenario in my mind is an incompatible or defective dimmer. Otherwise, your description is vague. Is this one circuit, one dimmer? Are there dimmers with only incand on them? Do the lights all flicker in unison or differently?

Multiple circuits and dimmers. Tried a new dimmer did the same thing.


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[Little Bill]

Find a circuit that has both lights that are flickering and receptacles. Get a lamp or maybe even a work light and plug into the receptacle. See if the lamp flickers like the lights. If so, you have eliminated the dimmer(s) and can look for other causes.
You mentioned you "checked" the neutral connections in the panel and meterbase. I have found corrosion under the wire both in the panel lugs and meter lugs that you couldn't see without removing the wire. I cleaned away the corrosion and the problem went away. So I would remove the conductors and check the lugs, not just the neutral (although that is the usual culprit) but all the lugs.

 

[synchro]

Good morning everyone. I have a customer who has an issue with all the lights in the house flickering on a dimmer. ...

Multiple circuits and dimmers. Tried a new dimmer did the same thing.

When you say "all the lights in the house flickering on a dimmer" do you mean that only the lights on a particular circuit flicker when its own dimmer is operated? Or do you mean that all of the lights in the entire house flicker (or at least some that are on different circuits) when just one dimmer is operated?

 

[K8MHZ]

It was suggested to replace the dimmer with a regular switch and see what happens. I see a dimmer was swapped with a dimmer, but nothing mentioned about testing with a standard switch. That would be the first thing I would do. Well, actually I would just bypass the dimmer with a wirenut.....but I would want to get the dimmer(s) out of the troubleshooting loop straight away.

 

[gar]

210811-1326 EDT

sparky1118:

Your posts are not an adequately clear description of your problem.

All I can determine from your posts is that ---
1, You have at least one light that flickers.
2. You have at least one dimmer somewhere, probably a phase shift dimmer.

For testing purposes I would like you to have ---
1. A good digital meter like a Fluke 27.
2. A good analog meter like a Simpson 260 or 270.
3. A 1500 W space heater.
4, A non dimmable CREE 9 W LED.
5. A 15 W tungsten incandescent bulb,
6. A good digital oscilloscope, and probes.
7. Suitable sockets and test leads.

Which of these you use and need will depend upon how the tests progress.

The CREE bulb will show very little flicker until large voltage changes occur.
The incandescent takes about a 2 V change to be noticeable.
The 1500 W 120 V heater produces about a 12 A load when warmed up.

With the digital meter ( I suggest the Fluke 27 instead of the 87 because the 87 resolution makes reading more difficult ) measure at the main panel relative to neutral each phase voltage, and to a screwdriver poked int the earth outdoors. Put the meter test leads directly on the incoming wires, not the terminating lugs. Then also make a hot to hot voltage measurement. You might watch each of these voltages for a short time to see how much typical fluctuation occurs. The changing voltage might be from house loads or power company variations.

Next do the same tests again, but with the 1500 W heater cycled on and off. And I mean with the voltmeter probes looking at the incoming lines. May not matter what circuit the heater is on. At my home the unloaded phase increases by about 0.3 V and the loaded phase drops about 0.7 V. This serves as a base reference.

Assume you have a single dimmer in question and an associated bulb for that dimmer. Set the dimmer at one point such that flicker is observed. At this time we don't not know what causes the flicker.

Cycle the heater on the opposite phase from the phase that the flickering light is on. This time I would suggest that the heater be connected directly at the main panel to eliminate a common neutral from the main panel between the heater and the light circuit. I did not mention above that measurements also be made inside the main panel after fuses and brokers. But, if there is a problem in the main panel you can do these tests later. If any flicker were to occur it should be an increase in light.

Change the heater to be on the same phase as the flickering light, but not is breaker.

At the main panel it would be good to measure the voltage from neutral to the output of the breaker that goes to the flickering light. Does this change enough to cause flickering?

Report back on whether these tests tell us anything.

.

 

[James L]

It was suggested to replace the dimmer with a regular switch and see what happens. I see a dimmer was swapped with a dimmer, but nothing mentioned about testing with a standard switch. That would be the first thing I would do. Well, actually I would just bypass the dimmer with a wirenut.....but I would want to get the dimmer(s) out of the troubleshooting loop straight away.

I would take the dimmer out and just wire nut the hot and switch leg together long enough to check, if I thought the dimmer was the issue.

Sounds like more than 1 switch, though, judging from the mention of both LED and incandescent doing the same thing

 

[Daolin]

Good morning everyone. I have a customer who has an issue with all the lights in the house flickering on a dimmer. I figured a neutral issue. So I tightened all the neutrals in the panel also checked the neutral at the meter socket. Everything seemed good. I called the power company and had them redo the terminations in the hand hole. Still nothing is working. This house is about 20 years old and they have never had this issue before they have both LED and incandescent fixtures that are doing the same thing. Any thoughts for what I may check next?


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Its the POCO's problem 98% of the time. Did you witness them redoing the connections? Are there other houses on the same handhole? Did they also tighten the connections of what feeds the hand hole? Here in Florida the POCO is notorious for saying we checked it and everything on our end is fine, when in reality they didn't check all the connections and I tell the customers to call them back and say it's still doing it. They send someone else out and sure enough its a loose neutral somewhere down the line on their end.

 

[ptonsparky]

Load up the incoming at the panel using temp receptacles if need be, while all other breakers are off. Hair dryers, heaters,
Check FOP across both line to load of the main breaker and the neutral. As Gar suggested, go to incoming conductor itself, not the lug.
Others have stated merely tightening a connection is not good enough. Remove and clean.

 

[ptonsparky]

Compromised neutrals at the SE and before will always cause voltage to go up on one leg and down on the other, Simultaneous observations or voltage readings must be done as loads are cycled.

Ignoring community wide metallic water piping.