LED Flicker

Factual Questions
1

First off, it’s not a problem with the house wiring, I did the work myself and properly and I know it’s tip top. Every now and again, one of my LED lights will flicker, and it subsides within a few seconds. It happened a few moments ago and its been well over a month since it last happened (the light is on 6 hours out of the day). I have read that LED lights that are dimmable have this problem sometimes, and since they use so little power, they are sensitive to any power fluctuation. I use a dimmer, and it makes sense. I’m not sure what to make of this and was looking for input on it. Any helps! I changed out the bulb and it still does it. Switch the bulb back and it stops, they are GU10 base bulbs so maybe its dirty contacts?

Thanks!

P.S. I repeat, the fixtures and household wiring are in perfect shape, it absolutely isn’t a problem with the household wiring.

2

Are you the only one in the house?
In my house, in my living room I have two (dimable, on a dimmer, but at 100%) LED bulbs that will flicker (once), when someone in the next room turns the lights on. In fact, I can tell when someone in there is ‘playing’ with the lights since the LEDs in the living room will flicker.
I could be wrong, but I’d wager that it has to do with the other lights beign CFLs since the LEDs only flicker when those lights turn on/off (and they are on a different circuit). They don’t do it when any other considerably higher loads turn on, ie stove, fridge, washer, AC etc. My WAG is that the CFL circuitry introduces some noise into the system.

So, barring someone turning a CFL bulb on else where in the house, the next thing I would try, other than ignoring it since it doesn’t seem to happen that often, would be to try another brand that isn’t as sensitive.

Lastly, when you say, when you repeat that the household wiring is in “perfect shape”, what do you mean by that? Have you checked it to make sure it’s within in the specs of the bulb? Have you checked to make sure your running at a proper 60hz? Is the socket getting 120v or is the power company supplying 130 or maybe there’s some resistance in the line and you’re getting 110 or 105 etc? A flicker can even mean a loose wire/neutral somewhere in the system. IOW “perfect shape” means more than connecting black to black and white to white. Especially when you’re trying to troubleshoot. Start by making sure everything up to the bulb is in good working order before deciding that that there’s a problem with the bulb.
Either that, or put the bulb somewhere else and see if it still flickers.

Lastly, you didn’t mention the brand/style/wattage etc of the bulb. They’re still in their infancy and the manufactures are still working out the kinks, so it’s possible that it’s just a bad bulb or an issue with those bulbs in general.

Another thing, you mentioned you think it may be the dimmer, so you really should take the dimmer out of the equation and see if that gets rid of the issue.

PS…you mention that the contacts may be dirty, A)clean them B) that doesn’t really jive with the ‘I’m the king of wiring, don’t tell me about wiring’ vibe you’re giving off here.

TL;DR,
1)Dimmer not meant for LED bulbs
2)bad/low quality LED
3)Wiring issue such as a loose neutral.
ETA, I just noticed who the OP is, I think you would do yourself a world of good to get over your fear of electricity. Don’t get me wrong, I do a ton of shade tree electrical work and I don’t mind answering electrical questions to the best of my ability, but you’re going to drive yourself batty if you worry about every possible electrical problem that has even the most remote chance of occurring.

3

If it is that rare, it could just be due to normal power fluctuations. The power company will occasionally switch things around a bit, mostly due to varying load conditions.

For example, they can switch large capacitor banks on and off of the line to correct the overall power factor, which is a measure of the inductance or capacitance of the line or system. Residential loads in general tend to be slightly inductive due to motors in things like vacuum cleaners, washing machines and dryers, etc. The overall power system works most efficiently when the inductance and capacitance balance each other out, so the power company will switch capacitors on and off of the line to balance out the inductance.

Generators can also be switched on and off of the system to compensate for different loading conditions. When I worked for Ohio Edison (several decades ago) the large coal plants and the nuke plants ran 24/7, but we had a variety of smaller plants (mostly coal, with some natural gas and one tire burning plant) that would be brought online or taken offline as the overall loads on the system varied. Generators also occasional fault and trip offline, though the power company tries to reduce trips as much as possible.

Many distribution lines can be interconnected in different ways. Sometimes the power company will switch these around a bit to even out loads or to bypass a localized fault. Occasionally they need to switch things around so that they can service a piece of equipment.

It’s also possible that one of your neighbors has turned a major appliance on or off. In most homes in the US, a single transformer will supply power from the distribution line to three or four homes. A large change in load on that transformer can produce a noticeable bump or sag on the voltage going to your house.

The long and short of it is that there are a whole bunch of reasons why you can get momentary glitches on your power line. Your lights may flicker a bit, but it’s usually no big deal. Even old incandescent bulbs could momentarily dim or brighten a bit.

Dimmable LEDs also tend to naturally be a bit glitchy. The reason for this is that your typical dimmer was designed for an incandescent bulb and it basically uses a triac to cut out part of the AC waveform. An LED bulb that isn’t designed for this can’t cope with the mangled AC waveform. However, even a dimmable LED can have issues with it. Since your flicker is pretty rare you probably don’t have an issue here, but for the benefit of others reading this, you can buy dimmers that are specifically made to work with modern dimmable LED bulbs.

Some of it is also just luck of the draw. Some dimmable LEDs work fine with certain dimmers and have issues with others. A different dimmable LED may work fine with the dimmer that gave the first bulb fits, but then have issues with the dimmer that worked fine for the first bulb. It’s a bit hit and miss. Again, switching to a dimmer specifically designed for dimmable LEDs will give you the best overall compatibility.

4

Just an FYI for the OP or anyone else who wants to check voltage. The voltage doesn’t have to be 120 exactly for it to be ok. The power company will typically guarantee 120 volts +/- 5 percent, so anything from 114 to 126 is perfectly normal. Some power systems only guarantee +/- 10 percent, which expands the range out to 108 to 132 volts. 10 percent used to be more common a few decades ago. Most power companies have tightened up their range to 5 percent these days. Your local power company should have a spec published somewhere on their web page. If not, you can contact them and ask what range they guarantee.

5

Be that as it may, the comment was really directed at the OP stating, twice, that they are sure the wiring is perfect. I was just trying to point out that ‘perfect wiring’ is more than making sure you have a hot, neutral and ground at the place you want a light bulb. Even ignoring the complexities that can show up in wiring (like shared neutrals, loose connections inside wire nuts, terminal screws not clamped down fully etc, there can still be the issue of the wiring problems outside the house or even problems with the actual electricity itself.

To look at it a different way, it’s like spending a month trying to figure out why your engine runs for 30 seconds then dies when you touch the gas pedal. You’ve rebuilt the carb twice, checked fuel pressure, looked for vacuum leaks, watched Scotty Kilmer yell at you about 65 different problems that are both major repairs and can be fixed in 15 minutes, but once in a while you need a second set of eyes. Someone that’s not so invested to step in and say ‘why don’t you throw a new set of plugs in there and see what happens’…and it works.

When you’re convinced it’s something complicated you can get tunnel vision hunting down a problem and not see the forest for the trees. IOW, the op said the wiring was perfect, but is it? Did they check it for 120v? While I’m guessing it’s either a bad bulb/dimmer combo (and I suggested swapping at least one of them out), it’s worth checking the basics firsts.

Of course, unless the OP can find a way to make this problem reproducible, it’s going to be a royal PITA to figure out why a single light bulb flickers a single time, once a month.

That doesn’t even seem worth the trouble, unless they feel it’s indicative problem bigger than a wonky LED bulb.

6

These flouro’s and LED’s have their own driver circuits inbuild, and if the circuit is very simple, its going to supply constant power to the lamp part… basically constant current, whatever the input voltage.

Now if its dimmable, its going to supply the current that is related to the voltage… that is, if input voltage drops 30%, its going to supply , for example, 30% less current…

So yes a dimmable device is going to show power fluctuations more than undimmable ones,
but they do all show fluctations more than incandescents because they use switch mode power supplies, and because light production is more directly due to electron movement - compare to incadescen’ts light production being due to temperature of the filament .

7

**Joey_P ** There is no fear of electricity. I just needed to understand some things about it and now I am interested in learning more about it, hence the questions. I wrote the part elaborating about knowing its not the wiring because I follow instructions, read manuals and had an inspector check my work. I was eliminating the possibility of wasting someone’s time with speculating about that, but I see that was a waste of time because I
had to explain again. Yes, the wiring is fine, and no there are not shared neutrals or anything questionable about any of the wiring. Done with your hostility yet? I apologize if you’re not being hostile, but your keyboard etiquette dictates otherwise.

engineer_comp_geek That’s some awesome info right there. That’s what I assumed from reading up about L.E.D.s being glitchy. I assume that if a neighbor uses an appliance that could cause that, it would have to be pretty substantial. Yeah, tested everything with a multimeter, 112V (115 when washing machine is off, lol) It must be that L.E.D.s are sensitive, remembered that I had some and put in a halogen (GU10) and no flickers. (I use LEDs to save some $). Thanks for the reply w/added info about distribution systems.

8

That makes perfect sense! I’ve seen LED’s flicker before (outside of my home/others) and wondered why they were “special” in that respect, and I figured it couldn’t possibly be an abundance of crappy LED’s out there.

9

You really never saw your lights flicker before you got this “sensitive” LED?

10

Are you trying to convince me or you?

Can cardboard touch metal conduit?

Does my fridge get hot enough to start a fire?

If a plug is slightly hanging out, will it start a fire?

If a plug is slightly hanging out, will it start a fire? Part Duex.

Will my fire extinguishers explode in a fire?

Can the plug fall out of my Xbox and start a fire?

Something about a bed and an outlet.

And in a total 180 that took the internet by storm,I think outlet covers are for decoration, I don’t think you can actually get a shock from house wiring.
Re-read some of these. Re-read all the threads you’ve started. There’s a difference between curious, having lots of questions, having racing thoughts about a narrow subject and an actual fear of something which is what you seem to have. It’s okay to be fearful (though I usually tell people to respect) electricity, but some of these things really don’t even make sense.
As you’ve been told in many of the threads, you really need to let this go. It’s consuming you.

11

I’ll bet you $20 it’s the dimmer. I bet you the problem would go away if you replaced it with one designed for LEDs or a normal switch.

12

Interesting. What is different about a dimmer switch designed for LED’s? I just came in to echo the OP’s issue. I recently swapped out 6 candelabra-style bulbs for comparable LEDs in my dining room chandelier. It is on a dimmer and I now notice a significant flicker every 30 minutes or so (never had any issue with regular bulbs). I was sure to get dimmable LED bulbs, but I never gave thought to replacing the dimmer switch itself. It may be worth a try since my dimmer switch certainly predates the existence of LED bulbs.

13

I am an apartment manager/maintanence man, and I do outside work for a Property Management company for several other apt complexes. I’ve installed several hundred LED light fixtures. I get the occasional call back due to flickering. It’s the fixture. As noted above, the technology is in its infancy. The occasional fixture will fail and flickering is the first sign.

14

I’m not an expert, so would welcome clarifications, but…

Incandescents are just hot wires. You apply less power, you get less brightness.

Dimmable household LEDs usually just have one brightness, and to dim one you don’t give it less power, but “pulse” the on/off so that it goes like ON-off-off-off-off-off-off-off-ON-off-off-off-off-off-off several dozen times a second. To the human eye, we perceive a pattern with more offs as dimmer, but in reality it’s just flickering really fast. At full brightness, on the other hand, it would be more like ON-off-ON-off-ON-off-ON-off. In fact, modern smartbulbs don’t need a separate dimmer, you can just use your phone or Alexa to tell it to go dimmer and it’ll handle all that internally.

Older dimmers decrease power to the fixture by just burning/wasting part of it as heat before it gets to the bulb. Newer dimmers (non-LED types) also cycle through rapid bursts of power in a similar fashion, which is still fine for incandescents. But neither type will work reliably with an LED, because the LED’s circuit boards want a certain amount of power at certain times and a mismatch will cause the circuit to either behave erratically or suffer internal damage.

Newer still, some dimmers are made to be compatible with some dimmable LEDs by basically understanding the bulb’s mechanics and giving it the right pattern of bursting power. There is not yet a universal standard, I think, but Lutron and others have compatibility tools on their website.

That was my understanding… more reading here:
https://www.reddit.com/r/explainlikeimfive/comments/4uniq3/led_dimmers_vs_incandescent_dimmers_whats_the/d5racs3/

15

then there are bulbs like Philips “warm glow” which incorporate red LEDs and shift color as you dim them to mimic incandescents.

16

Reply Awesome name, lol. Flickering so fast that the naked eye can’t catch it right? I suppose it does depend on the dimmer switch being newer or not, the new ones (manufactured about 2 years ago, installed almost a year ago) seem to be compatible as well. I just went the cheapass route and got some crappy L.E.D.'s. It seems these Philips ones work good, but given the price for the type of bulb, that’s why I took the cheap route:

(https://www.amazon.com/Philips-Reflector-Equivalent-Bright-Dimmable/dp/B01LMEQIMQ?SubscriptionId=AKIAILSHYYTFIVPWUY6Q&tag=duckduckgo-ffab-20&linkCode=xm2&camp=2025&creative=165953&creativeASIN=B01LMEQIMQ)

My dimmable LED incandescent clones never had an issue, but since changing the other types out with higher quality, I can’t replicate the flicker. I’m going to chalk this one up as solved. Still love all the information about why it happens! Thanks again everyone!
Joey_P If you re-read the posts in chronological order you would see that it was some unease caused by OCD that transformed into curiosity. I was asking question about wiring that was older, since all have been replaced, therefore no unease, therefore the questions don’t matter now. What is your fascination with trying to prove me wrong in any which way here instead of productive answers on the subject like everyone else?

17

To glom onto someone else’s thread, with my problem: I have been replacing light bulbs in the house with LED bulbs. Various manufacturers. They keep failing. Literally more than a dozen bulbs failed during last year. Not same manufacturer. I actually called the electrician to come in and check the wiring. They said it is fine.

I have no dimmer switches. I went around the house and replaced every dimmer switch with a regular one.

I have 18 foot ceiling and put in 4 LED bulbs into the fan up there - about 12 feet up. I don’t remember the manufacturer, but I made sure to buy expensive, legit manufacturer, LED bulbs. 2 out of 4 are out right now. Been maybe 1.5 years. Since I don’t have a ladder that all, replacing them would be a pain.

For me the whole reason to go LED is because they last a very long time. These have conked out after maybe a year or so. And no, they are not on all the time, just regular use.

Anyone have any idea why?

18

Even if nobody else is in the house, refrigerators, air conditioners and water heaters turn on/off by themselves. And if you have any appliances running, many cycle on/off by themselves - electric range/oven, refrigerator, dishwasher, etc.

19

Frankly, I think they do have failure rates higher than other consumer electronics. Of the about 30-40 consumer LED bulbs I’ve purchased, I’ve had 3 or 4 failures. That’s almost 10%. But what you’re seeing is crazy bad.

Where do you live? Could it be any of the following:

  1. Really unstable mains power (do you get a lot of brownouts/blackouts?)
  2. Are you a really hot or humid environment?
  3. Do you keep the LEDs in enclosed fixtures? While they don’t put out as much heat as an incandescent, they are also more sensitive to heat and ideally would be well-ventilated and not in an enclosed fixture.
20

Very few homes are built with 12 foot ceilings these days. Is this an older home? You might be getting a lot of vibration from people walking on the floor above where the lights are.

Another potential issue is heat. LED bulbs don’t emit as much heat as an incandescent, but an incandescent puts out heat fairly evenly around the bulb, where an LED has the heat concentrated at the base. This can be a particular issue in something like a fan since the lights point downward and the heat can get trapped around the base of the bulb. All of that excess heat can cause the bulbs to die an early death.

A third possibility is a voltage issue. If this is an older home, you might have a neutral connection going bad, which can result in overvoltages on many of your circuits. This isn’t very likely if an electrician checked the wiring.