LED lights blink in a regular pattern

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Old 04-30-20, 04:27 PM
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LED lights blink in a regular pattern

Hello, was wondering if anyone is familiar with this problem. The LED tubes in garage and LED bulbs in bathroom (all on the same circuit) blink in a regular and reproducible pattern. By "blink" I mean the intensity apparently goes noticeably up for just a short fraction of a second, high enough to make it annoying and hard on eyes. They do it even when nothing else is on in the circuit.

The pattern is: fourteen blinks about once every second, that is at about 1 Hz, are followed by 24 sec of normal light, then again fourteen blinks about a second apart, then again 24 sec of uninterrupted, normal light and so on.

Has anyone experienced this? Is the problem in the LED lights or in the circuit wiring, or in the appliances on other circuits, or in the city line? I can't exclude the city line or connection to the main because we've had loose neutral, loose phases several times before after strong winds (right now it's about 30 mph).

Any comment will be greatly appreciated. Best wishes, h.


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Old 04-30-20, 06:26 PM
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Check to see if there is anything else on the circuit. I know battery chargers can cause static on electrical circuits.
 
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Old 04-30-20, 06:33 PM
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Usually if the lights blink brighter..... it means something is drawing power on the opposite leg.
It's not always easy to determine what the cause is.
 
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Old 04-30-20, 08:02 PM
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Thank you, Tolyn, PJmax! What is the opposite leg? This circuit is dedicated to a few light fixtures, so nothing else is on it, no chargers or appliances.

However, I noticed that the microwave oven in garage, judging by the tone of it, loses some power after about five seconds of operation. The LED tube in garage changes its intensity when the microwave turns on and off. Even though the microwave is on a different circuit! Sounds like it might be a loose neutral again, after a few days of strong winds, either at the house end or the city transformer end, to which two more houses are connected.
 
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Old 05-01-20, 05:04 AM
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When did the blinking start relative to the LED bulb installation in the house and garage? Was any electrical done prior to the start of blinking? What did you do to determine there is nothing else on in the circuit? Do any of the LED bulbs have a dimmer control?
 
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Old 05-01-20, 05:24 AM
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Just a shot in the dark.

You said LED tubes.
Was this an upgrade from fluorescent?
If yes did you remove the ballast as some LED's say that they will run with or without the ballast.
If you did not remove the ballast I would do that.
 
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Old 05-01-20, 08:03 AM
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Beelzebob, Manden, appreciate the feedbacks! No, nothing has been done with any circuit for a few years. Don't remember when I noticed blinking first, the LEDs are a few years old, the regular blinking became noticeable probably half a year ago, at that time called city service, they found loose neutral at the house end. They have come a few times over the last three years fixing either loose neutral or loose phases -- all at the house end, never at the transformer.

Yes, tubes are just replacements for failed mercury tubes, one is still hanging in; no adjustment had been done.

Interestingly, now in the morning -- no blinking. It also happened in the past: the LED lights blinked for a day or two in that regular pattern, then stopped for a weeks, then came back.

Will see if it comes back later in the day when (a) the wind picks up in the afternoon; (b) when the neighbors on one side resume activity rebuilding the lower level; (c) when the house circiuts get some load.

What's also strange was that the garage microwave, which is on its own circuit, sounded weird yesterday like when the neutral is loose.

 

Last edited by harum; 05-01-20 at 08:19 AM.
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Old 05-01-20, 10:42 AM
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The problem with the neutral corrected by the poco would have affected the whole house so that couldn't be the cause of blinking on just 1 circuit. If you feel safe around live wires you could remove the breaker panel cover and tighten all the screws on the neutral buss. S[nce LEDs operate on DC, there is a AC/DC power supply in any LED fixture. The power supply contains components that have impedance which are frequency sensitive. Therefore anything that transmits/receives signals based on frequency could momentarily change the impedance in the power supply and cause the blinking. Could be things like the TV remote, garage door remote, microwave, cell tower near by, cell phone, etc.. Be observant the next time the blinking starts.
 
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Old 05-01-20, 05:11 PM
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Do you have any incandescent lights(old fashioned light bulbs)? Have some of them plugged in at different receptacles. Observe for dimming of these lights.

Loose neutrals can and will cause voltage changes, sometimes destructive, on different branch circuits also.
 
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Old 05-01-20, 09:10 PM
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Appreciate all the responses! Yes, the garage lights flash when the washing machine is plugged in or the dryer turned on -- even though they are on different circuits with different breakers; the microwave has been sounding weird also lately. This why I suspect loose connections again, which has happened several times before and as far as I can tell always after strong winds.

Today the LED lights blinked again at about 1 Hz, but without the fixed period of rest as yesterday. Binking went on for as long as couple of minutes, then stopped, then resumed after some random break. Once in a while they just flickered for a second or two. Will call the poco to check the connections, even though their last visit was in the beginning of March.
 
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Old 05-11-20, 09:23 PM
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Well, the two lights inside the oven also blink periodically (the brightness goes up for a fraction of a second) about once a second -- had never seen it before. They aren't LED as they get really hot, and the oven range is on its own 50 A circuit.

Would the problem be in the house main panel, one of the six circuits (like faulty breaker), or the city line? Thanks, h.

 

Last edited by harum; 05-11-20 at 10:33 PM.
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Old 05-12-20, 07:11 AM
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Did the brightness change in oven lights occur same time as brightness change in LEDs? Are the oven lights incandescent? What is their wattage?
 
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Old 05-13-20, 03:37 PM
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Beelzebob, the two oven bulbs are halogen appliance bulbs, each 120V, 25 or 40W. Not incandescent then. Not sure if the garage leds blinked at the same time with the oven bulbs. For sure, when the espresso maker in the kitchen is working, the garage leds start blinking at 1Hz; they are on different circuits. Dishwasher has no effect. It seems that high-wattage appliances on different circuits cause blinking of led or halogen lights. Will see if incandescent bulbs are also affected. Thanks again!
 
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Old 06-12-20, 01:17 PM
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blinking stopped about a week ago

Well, the blinking stopped a week or so ago, like it never existed. All the lights that were giving problems before are now back to normal. What is more noticeable though is this. The microwave, and my power tools in garage went back to normal, stable pitch during operation as before. They no longer sound like they are underpowered or that the current or the voltage is unstable. The garage has a dedicated 50 A line.

Is it reasonable to assume that the problem was on the city power company's end? Thanks for the help. Still confused here, h.
 
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