Ever since I put LED lights into our house almost 2 years ago, they would randomly flicker.  It only happened a handful of times a week and only lasts a few seconds.  I just chalked it up to LEDs being LEDs.

Within the last couple of weeks my UPS battery backup in my office started beeping as soon as the lights flicker.  My printer that is not on the UPS reboots itself.  The backup is on a different circuit than any of the LEDs.  We have the same LED canned lights on about 3 other circuits and they all flicker for the same amount of time.

My UPS has a utility on Windows that monitors power outages, under voltages, and over voltages.  Even though it beeps it does not record anything in any of those categories.

I'm at a loss to figure this out.

I also checked and my HVAC is not coming on when this happens.  Neither is my fridge or air compressor.  In fact any of those can come on and the lights don't react.  The only other appliance I haven't been able to track is the small freezer we keep in the garage.  Nothing else uses a lot of electricity in our house.  So I'm thinking if it's not the freezer then it has to be a voltage drop from the transformer?  


UPDATE:  Still no luck

Tightening the neutral bar and a few neutrals and grounds in my breaker panel didn't seem to change it.  Still did it Mon, Tue, and Wed.

I called the power company out and they came out yesterday.  He said the neutral at my main was just a little bit loose, but everything else looked good.  He did re-tighten it and requested a recording meter from corp, but didn't know if he'd be able to get one of them.  

So I needed a better way to track them.  My CyberPanel UPS software was just the personal edition and wasn't catching it all nor did it keep a log.  Looked into the Business edition and it would log every event. So I installed it.

Turns out it's happening a lot more than I thought.  

I thought it might be the freezer out in the garage, but it's unplugged.  Only other thing is the hot water heater.  You can't tell when it comes on.  So I'm going to turn it off today and see if that fixes it.

Any other ideas?

Attached File






UPDATE 2:

It seems to be happening at around the same time every day.  Now that I have the UPS logging it I'm starting to see a pattern. Tuesday and Wednesday weren't completely logged, so I was relying on seeing it myself and probably didn't catch them all. The automated logging started at around 7:15 PM Wednesday.  If the pattern persists it should happen again tonight around 10:30.

Also, I unhooked the water heater at about 11:45 AM Thursday morning to see if that was the culprit but it's not. I've isolated every single appliance at this point, including the TP Link Powerline LAN adapters. I also don't have anything on a schedule like this. My outside lights come on at dusk and off at dawn. So that's not it.

Monday
10:38 PM

Tuesday
7:33 PM

Wednesday
11:19 AM
7:25 PM
10:23 PM

Thursday
12:34 AM
3:27 AM
3:34 AM
11:24 AM
7:31 PM

loose neutral?

Where?  Inside the panel?

I forgot to mention it but we also have a whole house surge protector.  

Call your power company and have them come check the line coming to the home.

How many houses on your transformer. There's usually a number on the side of it which is the kw rating. May be too low for load. Our could be a loose neutral.

Yep.  Call utility provider.   Ask for check of service conductors coming into your house. 

If that checks out i would look at service jumpers and main breaker lugs on your side of the meter.

I believe there are 3 houses on it.  Should I ask them if they are getting voltage drops too?

I'm the only one on my transformer. It is not shared.

How old is the house?

Does this happen randomly or repeatedly after something turns on?

Any idea if all of the affected equipment is on the same phase?

Yes, ask the the neighbors.  It will help the POCO to troubleshoot the source of the problem .

Flickering lights can come from all sorts of things.

Many times troubleshooting problems like this where a backup ups sounds off there is a capacitor on the line that a switch is bad and won't close. It tries to close but won't and causes a slight disruption in the power. So small that most people don't bother to call to report it. Now if your neighbors are not having the same problem then it's something else and isolated only starting at the transformer connection going to your house.

Thanks everyone. Just checked the panel and found the clamp that connects the two neutral bars was pretty loose. Turned it over a couple times. Also found quite a few circuit neutrals on each bar that weren't snug as well as a few hots on some breakers that weren't very tight.

Hopefully that fixed it. The neutral coming in was really tight. Only thing I didn't check were the two phases coming in.

Picture of the loose clamp...
Attached File

At first you were talking about residential voltage drop, as that is a percentage number that the utility has to meet. Usually its 5% at the meter. If you are supposed to be served at 120/240, your VOLTAGE DROP is allowed to be at 114/228v, if its your utility is allowed 5% of drop.
If you have not checked your line voltage, thats the first thing to do. At the Meter. Its actually pretty rare that the utility is supplying customers at low voltage.
If you find low voltage at the meter, call the utility company at once, undervolting is terrible for motors and leds.
Then test voltage at the outlets. As the others have said, a loose N will create unstable voltages. There could be a failing capacitor in the UPS or your filter. The battery failing in your UPS will create problems too.

Like how much flicker? Like when the power is about to go out (couple flickers) or like a strobe?

A lot of "older" LED residential fixtures would over heat and flicker almost like a strobe. Had one of mine go bad and it looked like you were in a dance club. replaced it and no issues since.

J-

Only happened when they are dimmed down and it's like a slow strobe. The more they are dimmed down, the slower the flicker rate. And every single one of them flickers at the exact same rate. So it doesn't seem to be isolated to one bulb or even one circuit.

Like my last post says, I did find some loose neutrals. Hopefully that fixed it

UPDATE:  Still no luck

Tightening the neutral bar and a few neutrals and grounds in my breaker panel didn't seem to change it.  Still did it Mon, Tue, and Wed.

I called the power company out and they came out yesterday.  He said the neutral at my main was just a little bit loose, but everything else looked good.  He did re-tighten it and requested a recording meter from corp, but didn't know if he'd be able to get one of them.  

So I needed a better way to track them.  My CyberPanel UPS software was just the personal edition and wasn't catching it all nor did it keep a log.  Looked into the Business edition and it would log every event. So I installed it.

Turns out it's happening a lot more than I thought.  

I thought it might be the freezer out in the garage, but it's unplugged.  Only other thing is the hot water heater.  You can't tell when it comes on.  So I'm going to turn it off today and see if that fixes it.

Any other ideas?

Attached File

Could also be flicker on the grid you are seeing, LEDs can be more sensitive to voltage fluctuations. Some large variable loads can also wreak havoc on the grid.

Could be, but it's enough to cause my electronics to shut off and my UPS to go to backup for 6 seconds or so.  My LEDs have been flickering since I moved in, but it wasn't until the last week or so that my UPS started going to backup and my electronics started rebooting.  Before the UPS and electronics I chalked it up to LEDs being too sensitive.

Probably a transformer going bad. Once you have proof, you should be able get it replaced.It has to be something effecting all the circuits.
Do you know your neighbors? Talk to them, it may help narrow the problem down.

I did ask the tech about that and it turns out my transformer is not shared.

Sounds to me like your loosing one leg of your 240v.
Imho you need to call a licensed electrician to come have a look.
Be safe.

Ask them to put a flicker meter on the main incoming line to your house, also check with neighbors and see if the getting similar events.

Also what state are you in? If a high power load that uses an static VAR compensator or similar loses that piece of equipment everyone on that local grid will be affected.

Talked to one neighbor and he hasn't noticed anything.

I did ask them to put a recording meter on it, but the tech said those are usually used for "sensitive commercial buildings" like "hospitals & churches".  But he said he'd try.


Dad has been sick, but he was a lineman for a few years and has wired several homes.  He's coming out today to help me look at it.  I also have aluminum wire that goes from the meter to the house, but it's underground for about 150'.  It does look like it's in conduit though.  But I've read they corrode easily at the connections and that you have to pull them out and clean them up every so often.

First thought was incoming utility issue like the transformer going south, but has anyone checked where the individual circuit breakers attach to the busbar?  I've had those loosen up and cause issues like you're describing, I think you're getting to the point to have to contact a licensed professional to look at it.

Check your garage for a hidden subbasement where grandpa Rick keeps his alien-HIV infested baby eatter.

I had the same problem and eventually had the power company check. They found nothing. It turned out the compressor on my heat pump was failing. It would try to turn on but wouldn't and that caused the light flickers. It finally died and after putting in a new system the problem went away.  

check the lateral from the street to the pot

Only thing I've checked is the neutral at the main bar and it was solid.

Going to pull the meter today and clean all the main connections up

They probably don't trust the techs with them, but if your neighbors aren't getting any flicker it's an indicator that it's a localized issue. Do you get this on all the circuits in your house?

If its underground direct bury aluminum that is what I would look at .

Over head a bad crimp at the weather head or at the pole or transformer.

Neighbors having the same problem , Bad hot line clamp or stirrup , bad connection on the transformer possible bad transformer loose connection inside pot.

bad jaws in Meter.

If power is swinging up and down bad neutral connection in meter can or crimps or at pot or at main neutral connection.  

If the problem is only on one circuit in your house, pushed in connections on the back of receptacles  or loose connection ahead of the affected receptacle.

I forgot to mention that I'm the only one on this transformer.  It's not shared.

Thanks.  Tech did say that the transformer connections on the pole are all new and are the crimp style, which he also said he's never seen a bad connection using those.

Only one on this transformer, but one neighbor down stream from it does not have these problems.

Not isolated to one circuit.  Affecting at least 4 that I can observe (seems like it's only noticeable on electronics and dimmed lights).

There is conduit going down from the meter and up into the house.  I would think they wouldn't have ran conduit into the ground without running conduit all the way, but maybe not?

Are all the circuits affected on one leg?

panel breakers
1 2
3 4
5 6
7 8
9 10
1,4, 5, 8, 9 are 1 leg
2, 3,6, 7, 10 are another leg.

See post below.

No, they are on both legs.

Correct me if I'm wrong, but in your example, I thought

1, 2, 5, 6, 9, & 10 are on phase A
3, 4, 7, & 8 are on Phase B

Like shown below:

That alum wire to the transformer is likely not in conduit, probably direct buried.  Conduit only goes 18" underground.   If the wire got damaged during install the problems could just now be showing up.

Hopefully they found the issue in the meter today.

On a residential service, it would be uncommon to have  the alum feeders in conduit, the wire is direct burial rated and conduit just protects the above ground portion.   Which sucks if your wire goes bad.

Had a similar problem. Some lame ass lineman used an automatic line splice on my incoming power line on the neutral. I had no idea what that was, so I described it on GD and someone here told me what it was. I had about $3500 damages to electronic equipment. They installed a new cable to my house. Power company denied my claim through their legal department for my damages. The automatic line splice is for high tension cables and not for a short residential feed line.

I read the state law regarding power companies, wrote a letter to the power company using the law in Texas, and they sent me a check.

The transformer was good. My house was good. Their neutral cable was bad. It could have burned down my house.

OP is correct on the breaker layout, 1&2 are A, 3&4 are B, and so on.

The power gird is made for motors and the old incandescent bulb world.  A laser printer causes a small voltage drop when it's heating element cycles.  Digital dimmer switches can really screw up the sine wave on a leg.  Any myriad of devices cycling on and off can cause this.  A power line monitor is the only way to know if the problem is internal to your house or external on the grid.  These are DC devices trying to operate in an AC world.  

If you know someone who has a voltmeter like a Fluke 87 they may be able to detect some surges or sags depending upon their duration and magnitude.

Call the utility and see if they can put a voltage recorder on your service.  Had  the same type of thing happen and couldn't find the problem but was convinced that it was customer related.  Put a voltage recorder on for a couple of days and turned out the transformer had a small pinhole on top that was letting watter in.  All the computer battery backups would beep and the lights would flicler but you could not see it with a voltage meter,  it was very strange and i ended up having to eat crow but i got it fixed

Do any of the neighbors have any type of PLC light switch or LAN devices?

They communicate over the power lines and the voltages signals can cause LED lamps to flicker.

I talked to the guy I bought the house from this morning.  He had it built the house and did all the digging because he has an excavating company.  He said a couple years before he built the house, his dad cut a direct buried line with a shovel and it about killed him.  So ever since he has always put any type of wire in a conduit and said everything running to this house is in conduit, even the phone and cable.  

I can also see the conduit going into the ground on both ends.

I have a similar problem.

Hmmmm.  I thought about that, but didn't give it much consideration since my UPS is showing I lose power for 6-8 seconds.  I have 5 TP-Link Powerline Devices installed.  I'll pull them off and see if that fixes it. But I don't see it fixing the power drops.

Another thing you may try is when it is happening, shut off different breakers.  large to small and see if it affects the problem.  For example, shut off the water heater breaker, wait and see if it stops, if not turn it back on then shut off the air conditioning breaker. Etc.

I'm not an electrician.  Just a thought I had.

That would be great for you if it is all in conduit.  I don't think the feeder wires are the issue if that is the case.

UPDATE 2:

It seems to be happening at around the same time every day.  Now that I have the UPS logging it I'm starting to see a pattern. Tuesday and Wednesday weren't completely logged, so I was relying on seeing it myself and probably didn't catch them all. The automated logging started at around 7:15 PM Wednesday.  If the pattern persists it should happen again tonight around 10:30.

Also, I unhooked the water heater at about 11:45 AM Thursday morning to see if that was the culprit but it's not. I've isolated every single appliance at this point, including the TP Link Powerline LAN adapters. I also don't have anything on a schedule like this. My outside lights come on at dusk and off at dawn. So that's not it.

Monday
10:38 PM

Tuesday
7:33 PM

Wednesday
11:19 AM
7:25 PM
10:23 PM

Thursday
12:34 AM
3:27 AM
3:34 AM
11:24 AM
7:31 PM

If you live in a subdivision check with your neighbors on each side to see if they are having similar issues.  I had something like that happen at my old house with power surges and my UPSs beeping.  I happened to mention it to my neighbor one day and he realized he had similar things happening at his house, then neighbor on other side of him reported it as well.  So we had the power company come out and check things. Turns out the wires in the ground junction box that supplied 3 houses from the transformer weren't joined and sealed properly so they were corroding.  They remade the joints and everything was fine after that.

6 to 8 seconds is a considerable amount of time. You would be able to see that with your eyes no problem, but you're only detecting a loss with a ups and computer program?
Sounds like way less than 6 to 8 seconds and Maybe just a couple of cycles . Even still it shouldn't be happening and needs to be remedied.

If you're only seeing g it with computer or ups, have you tried plugging it in to a different outlet on a different circuit?

I know you mentioned your neighbors weren't having problems but are they on the same primary phase as you?

I mentioned in the other thread that sometimes distribution capacitor switches go bad, and they try to close  but fail. Everytime they try , it will flicker the lights enough that sensitive equipment will detect it and sometimes the eye but not always.
Just from experience of being a lineman for 30 years I have seen and heard all types of complaints. And true that  sometimes I'll go on a call just like yours and find good voltage under load. Very hard to detect a problem when  it's not doing g it right then. Like taking your car to a mechanic and he is unable to duplicate the problem .
If it's a connection it will get worse over time and never better or fix itself.

Sometimes it is so.ething unexpected and may appear (OK) from ground level.

I have found bad connections that appeared to look fine from the ground or even on the pole, except when you actually open it up and see there is a problem .

Edison put a new transformer in when we had something similar.  They came and tested one day and the transformer was in the same week.