Flickering LEDs

[Gunnar Alquist]

I just completed a 1-year warranty inspection on a 10-ish month old home. The only issue that I could not give a good answer for was flickering LEDs. This is happening at areas throughout the interior of the home. I first noticed it with the cheap recessed ceiling lights in the kitchen (I originally presumed that the builder used bottom-of-the-barrel ceiling fixtures) but later found the same (or similar) flickering at table lamps in the bedrooms.

No dimmers, regular toggle switches. Plus, the table lamps are not on wall switches.


The owner let me know that this is indeed throughout the home and an electrician had been out a couple of times to try to diagnose the problem, but couldn't. I did note some voltage drop at 3 receptacle outlets both upstairs and downstairs, but I have difficulty with that as the problem because the voltage drop did not occur at the lower amperage (10 amps) and the lights shouldn't be pulling much.

One other thing the owner/client reported to me was that the electrician said the flickering might be because this house is at the end of the (underground) utility line (at least currently at the end, as the subdivision is still being developed). That sounded weak to me, but who knows.


I was wondering if it might be some kind of issue with the utility company's transformer. Would a loose neutral (feed) cause this type of problem?


Since it appears to be systemic, I am leaning toward deferring to the electrical utility provider (PG&E) to check the connections at the meter and the transformer, but might also include deferring to an electrical engineer.


Anyone?
Anyone?
Bueller?

[Dom D'Agostino]

I've observed LED anomalies many times, existing homes and new construction, including flickers or pulses when other devices were engaged nearby. While you may have a whole house problem, I believe the fixtures have a propensity for being sensitive to what we have come to know as "everyday power distribution irregularities".
The fixtures are really just circuit based devices that are also mass produced, so who knows what kind of quality to expect.

As an aside, we used to be able to buy a replacement bulb for older than dirt light fixtures, now with most of the new units having integrated LED/bulb contraptions, I imagine the entire light will need to be replaced, since they haven't standardized on any bulb or module yet (or ever).

[Jerry Peck]

First, I looked at the photos, and my comments to myself (okay, I talk to myself ... got that out of the way) were that, gee, the voltage drop is inconsistent between the hot and the neutral (I like that tester as it tells you that, the SureTests that I used didn't tell me the individual voltage drop of each conductor) - and that comment lends itself to a potential partial answer, see below.


The owner let me know that this is indeed throughout the home and an electrician had been out a couple of times to try to diagnose the problem, but couldn't. I did note some voltage drop at 3 receptacle outlets both upstairs and downstairs, but I have difficulty with that as the problem because the voltage drop did not occur at the lower amperage (10 amps) and the lights shouldn't be pulling much.

With the voltage drop being higher on the hot than on the neutral, and with the conductor lengths of the hot and the neutral being essentially the same, that difference may very well be from connection resistance (poor connections, more so on the hot than the neutral, and with switches being on the hot conductors, that means more connections, which could mean more resistance.


One other thing the owner/client reported to me was that the electrician said the flickering might be because this house is at the end of the (underground) utility line (at least currently at the end, as the subdivision is still being developed). That sounded weak to me, but who knows.


I was wondering if it might be some kind of issue with the utility company's transformer. Would a loose neutral (feed) cause this type of problem?

Since it appears to be systemic, I am leaning toward deferring to the electrical utility provider (PG&E) to check the connections at the meter and the transformer, but might also include deferring to an electrical engineer.

That is another question I had - are all/most of the lights LED, or are there incandescent lights too? If there were incandescent lights too, were they flickering too, and at the same times as the LED lights? If so, that could indicate a loose neutral connection.

Also, check on the operating voltage of the LEDs, they may be more susceptible to low voltage than incandescents, which basically just get slightly dimmer with low voltage, but flicker with voltages jumping up and down.

LEDs may have mismatched drivers (power supplies): https://www.power-supplies-australia.com.au/blog/how-stop-led-lights-flickering (presuming lights are LED lights with power units, LED lamps in regular lights are a self-contained unit, power supply inside the lamp).

I noticed that the meter showed 122.6 volts, so being 'at the end of the line' for the utility supply should not be an issue, however, neutral issues are not uncommon on new construction (based on what I found, we - inspectors - were basically the first ones to actually test things with the house fully powered up). One way to check for a bad neutral is to find two receptacles on different bus bar breakers (usually found side by side in the panel), plug a heat gun or other portable heating appliance into a 120 volt receptacle on one bus bar, plug a volt meter (or your tester) into the receptacle on the other bus bar, read the voltage, turn the heat gun/other heater on, read the voltage again.

No change in voltage indicates the neutral connections are likely not an issue; big change in voltage indicates a neutral connection is the most likely issue (the neutrals main reason for being there is to keep the center point of the 240 volt system at the center ... 120 volts to each hot leg from the center grounded neutral).

[Gunnar Alquist]

I've observed LED anomalies many times, existing homes and new construction, including flickers or pulses when other devices were engaged nearby. While you may have a whole house problem, I believe the fixtures have a propensity for being sensitive to what we have come to know as "everyday power distribution irregularities".
The fixtures are really just circuit based devices that are also mass produced, so who knows what kind of quality to expect.

As an aside, we used to be able to buy a replacement bulb for older than dirt light fixtures, now with most of the new units having integrated LED/bulb contraptions, I imagine the entire light will need to be replaced, since they haven't standardized on any bulb or module yet (or ever).

Dom,

When you say "other devices were engaged nearby", do you mean some appliance in the home or next door? Since there is construction nearby (next door and farther on, I did ask if she had noticed the problem in the evenings (after the crews had left) and she said yes. As for in the home, There weren't any appliances on when I was there (other than the refrigerator and lights).

I would normally agree with the quality issue, but it seems to me that the bulbs in the personal table lamps would be a different manufacturer and less likely to be prone to the same problem as the permanent fixtures.

Yes, the fixtures are these low-cost, single-piece units. When they fail, it will be necessary to replace the entire fixture, which may not match the one next to it.


First, I looked at the photos, and my comments to myself (okay, I talk to myself ... got that out of the way) were that, gee, the voltage drop is inconsistent between the hot and the neutral (I like that tester as it tells you that, the SureTests that I used didn't tell me the individual voltage drop of each conductor) - and that comment lends itself to a potential partial answer, see below.

With the voltage drop being higher on the hot than on the neutral, and with the conductor lengths of the hot and the neutral being essentially the same, that difference may very well be from connection resistance (poor connections, more so on the hot than the neutral, and with switches being on the hot conductors, that means more connections, which could mean more resistance.

That is another question I had - are all/most of the lights LED, or are there incandescent lights too? If there were incandescent lights too, were they flickering too, and at the same times as the LED lights? If so, that could indicate a loose neutral connection.

Also, check on the operating voltage of the LEDs, they may be more susceptible to low voltage than incandescents, which basically just get slightly dimmer with low voltage, but flicker with voltages jumping up and down.

LEDs may have mismatched drivers (power supplies): https://www.power-supplies-australia.com.au/blog/how-stop-led-lights-flickering (presuming lights are LED lights with power units, LED lamps in regular lights are a self-contained unit, power supply inside the lamp).

I noticed that the meter showed 122.6 volts, so being 'at the end of the line' for the utility supply should not be an issue, however, neutral issues are not uncommon on new construction (based on what I found, we - inspectors - were basically the first ones to actually test things with the house fully powered up). One way to check for a bad neutral is to find two receptacles on different bus bar breakers (usually found side by side in the panel), plug a heat gun or other portable heating appliance into a 120 volt receptacle on one bus bar, plug a volt meter (or your tester) into the receptacle on the other bus bar, read the voltage, turn the heat gun/other heater on, read the voltage again.

No change in voltage indicates the neutral connections are likely not an issue; big change in voltage indicates a neutral connection is the most likely issue (the neutrals main reason for being there is to keep the center point of the 240 volt system at the center ... 120 volts to each hot leg from the center grounded neutral).

Jerry,

I have always disliked my Amprobe. Every time I plug the *&%$# thing into a GFCI protected receptacle outlet, the GFCI device trips (I have to select AFCI in order for the tester to not trip a GFCI). I sent it back to Amprobe with a description and one I received did exactly the same thing. I don't know if they sent me the same one, replaced it, or did anything at all, or if this is typical of the Amprobe tester. Nice to know it's good for something.

I did not find any incandescent bulbs in the home, but I didn't check the type of bulb in every table lamp. All of the built-in fixtures are LED and I asked the owner about the personal fixtures. She said all LED, but that might not be true.

I didn't go as far as you suggested regarding testing the neutral. I will let them know that I can come back and do further testing.

Just for clarification, there were only two pair of multi-wire circuits in this home. One pair was for the disposal/dishwasher and the other pair was the kitchen receptacle outlets. I realize that the voltage differential can occur if the neutral from the feeder or the service is loose or disconnected.

Thanks,
G

[Jim Luttrall]

I have a multi pack of LED bulbs in my truck to return to Costco because every bulb flickered in every lamp where I installed them. No problem with any other LED, CFL, or incandescent bulb. I first thought there was interference with something nearby or a heavy draw appliance but after swapping and swapping, I finally decided they are just defective. Time to try a different brand. These are FEIT brand.

[Gunnar Alquist]

These are FEIT brand.

I found the Feit CFLs to be unreliable. I have not had any experience with the LEDs. I don't know what brand these fixtures are.

[Jerry Peck]

Just for clarification, there were only two pair of multi-wire circuits in this home. One pair was for the disposal/dishwasher and the other pair was the kitchen receptacle outlets. I realize that the voltage differential can occur if the neutral from the feeder or the service is loose or disconnected.

I would use receptacles which are not on a multiwire branch circuit for the described test, that would avoid an issue with the single common neutral.

Just use two separate receptacles, which likely means that they are in different rooms. The best way to find them is to start at the panel and find two on different bus bars, verify that they are on different bus bars (there will be 240 volts measured between the two 120 volt hot conductors at the breakers), find out where they are labeled as going, verify that they are actually labeled correctly (test that the receptacles you are going to test on 'on', shut the breaker 'off' and verify that the receptacles are in fact 'off', then flip the breakers back on and make the test. Be nice and don't trip their computer while they are working on it, and explain that some clocks may need to be reset after the test. :)

[Randy Ashcraft]

I recently replaced a LED light for a customer in an 18 month old home. They told me where they had purchased the electrician installed led light. I returned the light (which was similar to a can light without the can) to the vendor. The vender just said oh another one and handed me a new one of a different brand. Apparently about 1/3 of the ones he had sold come back faulty. Vendor no longer sells that brand. Could be just bad unit from the factory made with cheap components. Have they changed any of them to see if a different one does the same? My $0.02

[Gunnar Alquist]

Randy,

That certainly is worth a try. I may email them to see if they have had any luck and let them know the feedback that I have received.

[Chuck Miller]

I too have had some issues with flickering. The more I hear about this the more I lean toward cheap fixtures. This is going to be a growing problem I think because most people go for the lower cost items (I know I often do) and suppliers buy bulk from cheap manufacturers. I think the market has been flooded with cheap crap from overseas because they can get away with it. Over the years I have noticed that most electrical fixtures are just plain garbage. It's going to be tough for a while on inspectors that say "oh, you have poorly made fixtures" when the client has paid top dollar to buy the home. Maybe if enough bad publicity gets out there the quality will get better. Plumbing fixtures are another issue but that's another thread.

[Ivan Fernandez]

Hi, on two occasions at two different properties I noticed the same thing. The first time at my Moms rental house. The LED lights started to flicker constantly as soon as she would start using the hot water. The house had a tankless water heater. Am am assuming the current draw from the tankless water heater caused it. The second time at my brothers house the same thing happened but in reverse. The LED lights were constantly flickering when they were turned on but stopped flickering as soon as you would turn on the hot water. His house had a tankless water heater as well. So, if this house has a tankless water heater look into it.

[Bill HUBRIC]

Just came access this same issue. It turn out to be a loose service wire point of entry lug. Hope this helps.

[david shapiro]

I don't know enough about the electronics of drivers, but even though the total load represented by a few LEDs is going to be low, could it be that the equivalent of inrush current is high enough that the drivers are seeing 107 volts or whatever and having trouble for that reason? Any time I see 12% or 16% VD I smell something wrong, wrong enough that I wouldn't look at the luminaires as the bad boys--even if another brand might be more resilient.

[Stan Clark]

Not this complicated maybe. I had this issue with one bulb in a fixture on a line of five and changed the bulb. No further flickering. Had a second issue... different line...changed the bulb... no further flickering. These bulbs were both less than a year old on new construction fixtures. Bought what I believed to be higher end bulbs (American brand). So far no issues. This may be Cheap LED bulbs made in China I think. Looking at posts...could you be overthinking this. Focus your efforts on the bulb to eliminate my assumption.

[Bill Shuman]

I just completed a 1-year warranty inspection on a 10-ish month old home. The only issue that I could not give a good answer for was flickering LEDs. This is happening at areas throughout the interior of the home. I first noticed it with the cheap recessed ceiling lights in the kitchen (I originally presumed that the builder used bottom-of-the-barrel ceiling fixtures) but later found the same (or similar) flickering at table lamps in the bedrooms.

No dimmers, regular toggle switches. Plus, the table lamps are not on wall switches.


The owner let me know that this is indeed throughout the home and an electrician had been out a couple of times to try to diagnose the problem, but couldn't. I did note some voltage drop at 3 receptacle outlets both upstairs and downstairs, but I have difficulty with that as the problem because the voltage drop did not occur at the lower amperage (10 amps) and the lights shouldn't be pulling much.

One other thing the owner/client reported to me was that the electrician said the flickering might be because this house is at the end of the (underground) utility line (at least currently at the end, as the subdivision is still being developed). That sounded weak to me, but who knows.


I was wondering if it might be some kind of issue with the utility company's transformer. Would a loose neutral (feed) cause this type of problem?


Since it appears to be systemic, I am leaning toward deferring to the electrical utility provider (PG&E) to check the connections at the meter and the transformer, but might also include deferring to an electrical engineer.


Anyone?
Anyone?
Bueller?

Gunnar, my 35 year experience as one of my state's largest utility Troubleman and Operations and Maintenance Supervisor tells me the are few options leading to the cause of the malfunction of many LED is this.

( 1 ) Many times a lower cost garage door opener will emit an RF signal between 300 and 400 MHz. Current high grade openers use the higher end due to the lower range causing RF interference involving LEDs. Hence the flickering you see especially in track lighting. Sometimes this will also cause termination of power.

( 2 ) Loose connection the homeowners panel. You indicated ALL the LEDs in the home do the same flicker. Normally this will be either a voltage or the neutral connection to the specific run. Main breaker is suspect.

( 3 ) Loose voltage connection in the main transformer. You didn't indicate and power loss in the home such as resets of digital clocks showing the loss of power.

( 4 ) This is not where I would go first. A minor looseness of the main neutral connection in the transformer. This doesn't appear to be your issue by the voltage measurements you show in the pics. A loose main neutral is apparent by a 'voltage shift' under load. This load can be as little as a microwave or blowdryer being turned on. The shift depending on the load size can be between 0 and 120. What comes in is returned to the source via the neutral and if it is not solid then one of the legs will return the voltage to the source. You will see it on the meter and the shift is the exact opposite for the other. One leg in the home will become brighter or dimmer depending on its connection side in the panel. If the voltage on leg A is 110 then B will be 130, that being said the voltage measured normally is 120 per leg as normal.

( 5 ) The 'Flicker Ratio' of the home is lower than the required percentage. Meaning the transformer is either too far away, hence the voltage drop causes flicker on most lighting in the home as designed or the service wire size is too small. This would be unusual as most utility set the low range for NEW homes at 7% where as older existing home, many years, were around 5%. 5% drives homeowners crazy as the lights are always dimming when appliances are turned on, even a microwave will cause this annoyance.

( 6 ) Shared load, meaning too many houses or one in particular is causing temporary voltage loss due to a high load in a neighbor's home downstream from your problem house. Grow houses are sometimes found because of this but a workshop with a LARGE horsepower lathe or equivalent tool will cause this but it is seen in incandescent also.

My first move in solving this would be the simple disconnect the garage openers. Then tackle the tougher ones like starting with the Main breaker voltage per leg and breaker integrity. If the Tmen who were supplied by the utility did not mention they found a loose connection it probably is the panel or the other mentioned. Good luck. Bill PS apology if typos or run-on sentences cause any confusion.

[Richard Bushong]

I just completed a 1-year warranty inspection on a 10-ish month old home. The only issue that I could not give a good answer for was flickering LEDs. This is happening at areas throughout the interior of the home. I first noticed it with the cheap recessed ceiling lights in the kitchen (I originally presumed that the builder used bottom-of-the-barrel ceiling fixtures) but later found the same (or similar) flickering at table lamps in the bedrooms.

No dimmers, regular toggle switches. Plus, the table lamps are not on wall switches.


The owner let me know that this is indeed throughout the home and an electrician had been out a couple of times to try to diagnose the problem, but couldn't. I did note some voltage drop at 3 receptacle outlets both upstairs and downstairs, but I have difficulty with that as the problem because the voltage drop did not occur at the lower amperage (10 amps) and the lights shouldn't be pulling much.
I did about 10 yrs in the URD field and since the house is fairly new , it sounds like moisture intrusion in a splice on the underground service or even a nick in the sheathing, even if in conduit you can still get water intrusion through splices or cable damaged when pulling or disturbed by a 3rd party. Something to have checked since they said it was at the end of the line.


One other thing the owner/client reported to me was that the electrician said the flickering might be because this house is at the end of the (underground) utility line (at least currently at the end, as the subdivision is still being developed). That sounded weak to me, but who knows.


I was wondering if it might be some kind of issue with the utility company's transformer. Would a loose neutral (feed) cause this type of problem?


Since it appears to be systemic, I am leaning toward deferring to the electrical utility provider (PG&E) to check the connections at the meter and the transformer, but might also include deferring to an electrical engineer.


Anyone?
Anyone?
Bueller?
I did about 10 yrs in the URD field and since the house is fairly new , it sounds like moisture intrusion in a splice on the underground service or even a nick in the sheathing, even if in conduit you can still get water intrusion through splices or cable damaged when pulling or disturbed by a 3rd party. Something to have checked since they said it was at the end of the line.

[Dom D'Agostino]

Focus your efforts on the bulb to eliminate my assumption.

But the majority of new LED fixtures don't have "bulbs" or even replacement elements. The LED is integrated into the fixture, and is not an off the shelf part. Many new "recessed" cans are thin (1/2 inch) discs with no replaceable parts whatsoever. Makes chasing down an errant bulb/diode/emitter a bit more challenging.

[Stan Clark]

Point taken. This was my issue with a screw- in ?LED? bulb. Ultimately, it would seem the source of light is the same as those stated in your response only the package they come in is different. Just an observation...

[Duane Thaxton]

I just completed a 1-year warranty inspection on a 10-ish month old home. The only issue that I could not give a good answer for was flickering LEDs. This is happening at areas throughout the interior of the home. I first noticed it with the cheap recessed ceiling lights in the kitchen (I originally presumed that the builder used bottom-of-the-barrel ceiling fixtures) but later found the same (or similar) flickering at table lamps in the bedrooms.

No dimmers, regular toggle switches. Plus, the table lamps are not on wall switches.


The owner let me know that this is indeed throughout the home and an electrician had been out a couple of times to try to diagnose the problem, but couldn't. I did note some voltage drop at 3 receptacle outlets both upstairs and downstairs, but I have difficulty with that as the problem because the voltage drop did not occur at the lower amperage (10 amps) and the lights shouldn't be pulling much.

One other thing the owner/client reported to me was that the electrician said the flickering might be because this house is at the end of the (underground) utility line (at least currently at the end, as the subdivision is still being developed). That sounded weak to me, but who knows.


I was wondering if it might be some kind of issue with the utility company's transformer. Would a loose neutral (feed) cause this type of problem?


Since it appears to be systemic, I am leaning toward deferring to the electrical utility provider (PG&E) to check the connections at the meter and the transformer, but might also include deferring to an electrical engineer.


Anyone?
Anyone?
Bueller?


Gunnar, personally I have always had problems with Feit LED's flickering. Once I changed out those fixtures to those manufactured by NICOR, my problem was solved . . . no other corrective action. Duane

[Wayne Domina]

Try a test by turning on or off motor devices like hvac, stove, bathroom or ceiling fans if available. It may be a wire bundle issue. Wires may not be properly separated near the service panel. sometimes a new electrician will bundle up to and above the top plate causing interference.

[Bill Kriegh]

Try a test by turning on or off motor devices like hvac, stove, bathroom or ceiling fans if available. It may be a wire bundle issue. Wires may not be properly separated near the service panel. sometimes a new electrician will bundle up to and above the top plate causing interference.

I'm not sure what you are referring to here, but wiring shouldn't have to be done any differently than it otherwise would have been just so LED fixtures will work.

What is "properly" separated near the panel?

A quality fixture should be happy with a 120 volt supply no matter how the wire gets it there.

[Dwight Doane]

No dimmers, regular toggle switches. Plus, the table lamps are not on wall switches.


The owner let me know that this is indeed throughout the home and an electrician had been out a couple of times to try to diagnose the problem, but couldn't. I did note some voltage drop at 3 receptacle outlets both upstairs and downstairs, but I have difficulty with that as the problem because the voltage drop did not occur at the lower amperage (10 amps) and the lights shouldn't be pulling much.

One other thing the owner/client reported to me was that the electrician said the flickering might be because this house is at the end of the (underground) utility line (at least currently at the end, as the subdivision is still being developed). That sounded weak to me, but who knows.


I was wondering if it might be some kind of issue with the utility company's transformer. Would a loose neutral (feed) cause this type of problem?


Since it appears to be systemic, I am leaning toward deferring to the electrical utility provider (PG&E) to check the connections at the meter and the transformer, but might also include deferring to an electrical engineer.


Anyone?
Anyone?
Bueller?[/QUOTE]


What you have is some cheap LED units with not so good drivers installed (either as part of the unit or as part of the circuit like a ballast) . I have had LED units installed in several buildings and - yes there were units that were defective that did not cycle fast enough. (Huh ? LED unlike incandescent bulbs these lights work by tuning on and off very fast like a square wave unlike a sign wave. These units are most likely all defective and someone got a very good price on them. (the real hint was they were on toggles switches) . one possible fix (Hail Mary Pass) is to put an incandescent bulb on the same circuit (sometimes it helps for some reason - sometimes it doesn't )

As for the lights dimming - I suspect another culprit - like noise on the incoming power and voltage swings - the only way your going to really see this is to install a data logger along with an oscilloscope - This is where your electrical engineer will come in to evaluate the power. Problem #2 PG&E has issues with transmission lines that have been damaged by fire the last few years. Electrical Companies don't like to deal with issues especially when they are in Bankruptcy (am I correct PG&E is in bankruptcy). Until someone can really look at the incoming power you don't know the cause unless there is really poor wiring or a bad power distribution box (not very likely) OK in fairness most of the time I deal with 3 ph power this is where you see imbalanced power and something smells bad here.

[Richard Bushong]

No dimmers, regular toggle switches. Plus, the table lamps are not on wall switches.


The owner let me know that this is indeed throughout the home and an electrician had been out a couple of times to try to diagnose the problem, but couldn't. I did note some voltage drop at 3 receptacle outlets both upstairs and downstairs, but I have difficulty with that as the problem because the voltage drop did not occur at the lower amperage (10 amps) and the lights shouldn't be pulling much.

One other thing the owner/client reported to me was that the electrician said the flickering might be because this house is at the end of the (underground) utility line (at least currently at the end, as the subdivision is still being developed). That sounded weak to me, but who knows.


I was wondering if it might be some kind of issue with the utility company's transformer. Would a loose neutral (feed) cause this type of problem?


Since it appears to be systemic, I am leaning toward deferring to the electrical utility provider (PG&E) to check the connections at the meter and the transformer, but might also include deferring to an electrical engineer.
I did URD work for a power company for 10 years and we used to find this problem when a line got nicked or a splice wasn't water tight and you had water intrusion , this can happen even in conduit. Another cause is possibility of a lightning strike near the transformer causing a splice to burn, this happens mostly on direct burial on the primary feeder even with lightning protection. I would call the local power company since an electrician couldn't determine what is causing it. I live in WV and we have trouble with every buried utility in the area because of all the rock and subsidence problems.


Anyone?
Anyone?
Bueller?


What you have is some cheap LED units with not so good drivers installed (either as part of the unit or as part of the circuit like a ballast) . I have had LED units installed in several buildings and - yes there were units that were defective that did not cycle fast enough. (Huh ? LED unlike incandescent bulbs these lights work by tuning on and off very fast like a square wave unlike a sign wave. These units are most likely all defective and someone got a very good price on them. (the real hint was they were on toggles switches) . one possible fix (Hail Mary Pass) is to put an incandescent bulb on the same circuit (sometimes it helps for some reason - sometimes it doesn't )

As for the lights dimming - I suspect another culprit - like noise on the incoming power and voltage swings - the only way your going to really see this is to install a data logger along with an oscilloscope - This is where your electrical engineer will come in to evaluate the power. Problem #2 PG&E has issues with transmission lines that have been damaged by fire the last few years. Electrical Companies don't like to deal with issues especially when they are in Bankruptcy (am I correct PG&E is in bankruptcy). Until someone can really look at the incoming power you don't know the cause unless there is really poor wiring or a bad power distribution box (not very likely) OK in fairness most of the time I deal with 3 ph power this is where you see imbalanced power and something smells bad here.[/QUOTE]

[Mike Clarke]

I purchased a few of those ECOSmart brand ones from home depot not long ago, everyone was flickering occasionally same time, other LED bulbs had different brand were not. Think could have been a combination of a bad bulb generating harmonics and they were cheap and the others no filtering out causing the flickers, but was only happening to that brand. Bought other brand again replaced and no problems.
weird