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I have a very troubling issue with my LED lights that so far two qualified electricians AND the power utility have not been able to uncover. I have been working on this for 1 month (hours of research) and we're no closer than when we started.

The issue is this: All LEDs in my brand new house (built April 2021) that contain circuit boards, or are run off a LED driver (does not affect simple LED bulbs plugged into conventional light sockets) begin to strobe at a regular interval after they are switched on. 44-55 seconds from flicking the switch the light will strobe for 5 seconds and then go back to normal.

The lights do not strobe at the same time, the countdown to strobing begins when each light circuit is switched on. This is stumping us as it would be much easier to identify the issue if all the lights strobed at the same time (suggesting a central supply issue). But that's not the case.

Morever, this is NOT your typical dimmer switch issue, I've spent 20 hours on this so far and eliminated the following COMMON causes:

  1. Dimmer switches - zero in my house
  2. Appliances - issue occured before appliances were installed
  3. Outlet connections - issue occured before any devices were connected to any outlets
  4. Switches - switches are basic on/off and have ALL been tightened
  5. Light bulbs - this issue is occuring in 4 completely different brands and styles of integrated LED lights
  6. Voltage - power utility AND electricians both confirmed 118 volts at the source and panel
  7. Panel - the panel has been checked and is perfect, all connections checked by two electricians
  8. Breakers - this is affecting 4 different circuits, all breakers checked and are correct for the panel

And finally: turning off all breakers, except for a strobing light circuit, does not change the behaviour, the lights will strobe even if they are the only circuit on in the entire panel. :(

The ONLY tell I have right now, which hopefully means something to someone, is if I flick off two breakers for my wall outlets (which contain GCFIs if that matters) and then flick them back on, two circuits will stop strobing completely for at least 4 hours. No electrician can explain this, but the behaviour has been observed true 3 times now.

TL;DR - 4 different types of LEDs with integrated circuitry strobe at regular intervals on 4 different circuits. Common culprits have all been checked. When two breakers are turned off, strobing on two circuits ceases for at least 4 hours. What is this indicitave of?

Update: this affects 19 model: LPDL4 Stanpro Drivers/Standard 4" LED downlights, 2 bathroom lights with integrated LEDs, 5 under cupboard mini-LED downlights, and a chandelier with integrated LEDs. The bathroom lights and chandelier are completely different than the Stanpro drivers. The Stanpro lights are very high quality pieces.

Update 2: Electrician combined the 4 light circuits into 2, this caused the strobing to cease for 13 hours, the strobing has returned exactly like before. We can eliminate the lights as an issue, they worked fine for 13 hours. As well, central power delivery can't be the issue given the same finding.. I wonder if it's the panel itself.

Update 3: Picture of the original panel wiring: Picture of the original panel wiring

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  • 1
    It sounds like the incoming power has some heavy transients. Just for grins try a regular light bulb and see if it is OK. If so then connect it to one of the LED circuits and see if it helps. Try something in the 100W range.
    – Gil
    Aug 19 at 2:13
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    What is your hot-neutral voltage? Check at least 5 or 6 circuits, and by circuits I mean breakers. Aug 19 at 4:36
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    It is extremely unlikely, but within the realm of possibility that you did buy batches of bad fixtures. When building a new house, all the parts are purchased in bulk from the same supplier at the same time. If there was a bad batch (maybe just one chip in the controller that could be common to all the fixtures), you may have picked up 8 or 10 with the same lot number from the same supplier. Have you tried replacing any of the fixtures with newly purchased ones? If a brand new fixture works fine, there's your culprit.
    – FreeMan
    Aug 19 at 16:08
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    More experiments ... Remove one or two of the flickering lights, install a plug on it, take it to work or to a neighbor's house and plug it in ... see if it flickers. At least you can determine if the alien forces are within your house or surrounding your whole area.
    – jay613
    Aug 19 at 16:38
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    More experiments ... this is really stretching it and I'm sorry but may as well ask ... if you can get access to a recording oscilloscope, track the signal on the input and output side of the driver from power-up time to a few seconds after the flicker stops. I have no idea what we'll do with the data but there's not a lot else to try.
    – jay613
    Aug 19 at 16:46
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Is the photo you posted before or after the electrician changed it. If it is after you have some big issues. This is what is called an Edison circuit (2 hots sharing a neutral) and the wiring being that way is likely the root cause of the strobing effect you are seeing. Try turning off the red leg to both and see if the flickering stops. You have another issue in the panel as well, for a 2 wire shared neutral circuit, the breaker MUST be bonded so if one side trips the other trips as well. Edit: by bonded I mean the handles, or a single handle 2 pole breaker

Adding an answer cause I cant comment yet

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  • thank you, I am going to try just running the black side, this means the reds will just sit unconnected in the panel and hot, correct? Is there a solution to this if it is the root cause?
    – AutoM8R
    Sep 1 at 22:04
  • oops I understand now. The black and red wires were combined into a single beaker by my electrician to fix this edison circuit. Is that legit? I am going to wire it the original way, then disable just the red wires as you say and see if the strobing ceases. Thanks for the suggestion. If it does, is there a fix beside rewiring?
    – AutoM8R
    Sep 1 at 22:13
  • @AutoM8R if the breaker is rated to be double lugged then yes both wires can be on the same terminal of a single pole breaker essentially making it one circuit. Unfortunately there are very few options if this fixes it outside of rewiring. You can possibly grab the black wire if both are present and get everything on to one leg and abandon the red in place
    – Matt
    Sep 2 at 1:18
  • thanks for that, I combined the red and black wires from both Edison circuits into one breaker, creating a single circuit. However, still strobing, so I assume it's not the Edison circuit causing this?
    – AutoM8R
    Sep 3 at 17:53
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Gonna need to see pictures of the lights or part numbers. This sounds like the drivers are suspect. Even though they are different brands the drivers are all likely to be from the same junky supply in china, made by the thousands and sold under 3000 different brands.

I second with Gil, plug something that is a reasonable load in to the circuit and see if it is strobing too, if its not then I would start looking for either a crazy amount of noise on the lines or more likely bad fixtures right out of the box.

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  • I appreciate it, but 2 of the 3 fixtures use completely different drivers. It would have to be 23 fixtures bad from the box, super unlikely. How would one go about checking for noise on the lines? Thanks!
    – AutoM8R
    Aug 19 at 15:31
  • if that box of dimmer sat in a hot warehouse all summer because of the pandemic, it could have dried out the driver's capacitors and damaged them all in the same way.
    – dandavis
    Aug 19 at 18:38
  • @dandavis lights were sourced from different warehouses in fact, lights work fine for hours if I switch off two breakers. So lighs can be eliminated as such.
    – AutoM8R
    Aug 19 at 19:40
  • @AutoM8R O-scope, several Fluke instruments among a couple other brands out there will measure noise. It sounds like your going to want to measure with the 2 breakers off and on and try to see the difference. What is on the 2 breakers you are switching off?
    – Matt
    Aug 19 at 20:18
  • @Matt those breakers control wall outlets, 5 of which are GCFI. Going to try this test thanks!
    – AutoM8R
    Aug 19 at 22:25
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I can't comment - so you get an answer. I agree with Matt's comment. It's amazing how many different brands use the same source for their products and then just make some minor cosmetic changes. This is very true in the smart lighting industry as well.

The one commonality you mention is that the lights in question have a circuit board. Are these smart devices? IAC, as Matt suggested, if the boards call came from the same supplier, then something could be interacting with the boards.

Others here know much more than I, but possible interferences could be hacked circuitry, a device in your house that sends a signal that is misinterpreted by the boards, or even some outside source.

While I doubt it's part of the problem, I would also check the line voltage, both once the lights are turned on and then again, when they start to flash.

If any of the lights are easy to remove, then consider taking one out and having an electrician try it back at their office.

Also check to see if you have neighbors with antennas (short wave or otherwise) that might be broadcasting.

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  • Thanks for the attempt, we know the lights work because I can make them stop strobing by flicking off and on two breakers. Two different sets of lights are fixed by this for at least 4 hours. So it's not the lights :(
    – AutoM8R
    Aug 19 at 17:18
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Turns out the issue was in the panel. There were 4 circuits and we combined these into two circuits and the problem was solved!

See the attached picture, the electrician said we converted the circuit from a 3-wire breaker to a 1-wire breaker if I get his terminology correct. So as you see in the picture the two circled breakers were combined as one on both sides leaving two light circuits instead of 4.

two breakers on left combined into one, two breakers on right combined into one

This is a before picture, the red wires on both sides circled were combined with the black wires to form two circuits from the circled four breakers. After picture incoming soon.

Update: Unfortunately after 13 hours the strobing came back on all circuits. SO, now the whole panel is mimicing the behaviour I found when I flicked off the two breakers (eleviating the strobing for hours). Something must be building up in the panel and disconnecting the breakers is fixing this build up.

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  • Is that picture the new situation or the old one? I cant really tell. Could you add before/after pics?
    – Tonny
    Aug 20 at 10:11
  • @Tommy good point, this is before, after will be posted ASAP
    – AutoM8R
    Aug 20 at 11:21
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    Which two breakers were you switching off to "fix" the problem? It looks like they were both (improperly done - no handle ties) MWBCs, so somewhere there was some noise or other issues. Have you checked to ensure that the new single breaker can support the entire load expected now?
    – FreeMan
    Aug 20 at 12:18
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    @FreeMan put it in the OP, we're going to go down that path now. I am going to push for a new panel and new breakers as it seems to be a systemic panel issue..
    – AutoM8R
    Aug 20 at 15:58
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    Please tell me if this summary is correct: All the circuits in the panel were turned off except the two top left, which are outlets including some GFCI ones, and the four circled, which include all the impacted lights. When you combined the four circled circuits into two, the time to flicker went from 44 minutes to 13 hours. Is that accurate?
    – jay613
    Aug 20 at 16:41

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