As an electrician, I have come across my fair share of bad domestic lighting installations. Often it will be by a contractor but usually, the homeowner will install LED lights as a DIY project.
The problem arises when the LED lights start buzzing and flickering due to unmatched parts. This could be such as step-down transformers, dimmers, and poor-quality LED lights.
Table of Contents
- 1 LED lights flickering on dimmer control
- 2 How to select good quality LED bulbs?
- 3 LED light bulb glowing when off at the dimmer switch
- 4 LED lights buzzing no dimmer switch
- 5 How to fix flickering LED lights
- 6 Do LED lights flicker when burning out?
- 7 Conclusion
LED lights flickering on dimmer control
The majority of LED light buzzing and flickering problems come from an incompatible dimmer control switch or un-dimmable LED lights. Yes, that is a thing you must have dimmable LED lights. When you purchase your LED downlight or light globes, spend a few extra dollars to get the dimmable versions.
Also, check how many LED downlights you have on one circuit. Then check the wattage of the LED dimmer mechanisms. They will all have a rating for minimum and maximum load.
For example, if your dimmer switch has a LED rating of 150 watts then you can have 15 LED lights rated at 10w each. But I would take the maximum load up to only 14 or fewer LED downlights to be safe. We don’t want to overload the dimmer switch.
Some more advanced LED dimmer mechanisms now have an adjustment when to try and smooth out the LED lights buzzing and flickering. Just turn on the lights and adjust the wheel up or down to take out the buzzing or flickering.
How to select good quality LED bulbs?
Most reputable light bulb retailers will only buy certified, rated and quality-tested LED light bulbs.
You can avoid low-quality LEDs by:
- Purchasing your LED light bulbs from a reputable store in your area. Don’t buy them from eBay because they are cheap.
- Only buy brand-name LEDs – such as Bell, GE, Sylvania, Osram, and Philips globes as they are synonymous with quality.
LED light bulb glowing when off at the dimmer switch
This is a problem that mainly affects lower-quality light globes. What is happening is that stray electricity is being generated in the electrical cables going to the LED light through induction or capacitance. This is mainly an issue with low-quality light globes that don’t have proper full-wave bridge rectifier circuits.
Where does this residual electricity come through?
- The neutral wire in the circuit is not properly bonded to the earth cable or bus bar. The other reason is that the earth wire is at too high a resistance to the earth’s main house stake. Therefore creating a small current that is “powering” your bulb.
- Another reason is a tiny pick-up of electricity generated from cables running alongside each other due to electromagnetic induction. This low voltage induction from the live wire causes the bulb to glow.
- Faulty dimmer control circuit.
You can read more about how to fix your LED light that stays dim when the switch is off here.
LED lights buzzing no dimmer switch
If your LED lights are buzzing but there is no dimmer control switch installed then you most probably have a faulty LED light. Over time these LED and CF lights can fail, often it is the internal capacitors that fail.
This high-pitched buzzing noise can be often heard during the startup of the light and can sometimes go away when the light warms up.
If it stays on the whole time then it’s time for a new LED light. The problem won’t go away it will just get worse. Check that you don’t have a dimmer switch installed somewhere in the circuit. I have disconnected dimmers before as the clients would rather have the lights on full brightness and no flickering or buzzing due to incompatible globes.
How to fix flickering LED lights
The easy way to stop flickering LED lights is to replace them with a new quality LED light. If you have your lights on a dimmer circuit then make sure to purchase LED lights that are dimmable.
Purchasing LED lights that are not dimmable and putting them in a circuit that has a dimmer switch will often give you light flickering and buzzing noises.
If you have a dimmable LED light and it is still flickering you could open it up and see if one of the capacitors has popped or expanded.
Stop LED flicker capacitor
In most LED transformer circuits you will have a smoothing out capacitor. This is designed to take the choppy DC voltage from the full-wave bridge rectifier and smooth it out. This helps to reduce light flicker and buzzing.
Over time these stop LED flicker capacitors will pop or fail, You can tell by the raised top section of the capacitor.
Now if you find that the 12v LED transformer circuit has a blown capacitor you can either replace it yourself with the same type or buy a compatible LED driver transformer.
Check out the video below on how to fix a flickering LED light by replacing the capacitor.
Do LED lights flicker when burning out?
Yes, this can be a problem due to the capacitors failing and not being able to smooth out the clipping current from the full-bridge wave rectifier. It is not so much the LED diode themselves that burns out but the driver circuit that converts AC into DC voltage that is causing the flickering and buzzing noise.
12v led lights flickering problem is often solved by replacing the transformer connected to each individual LED light.
Are buzzing LED lights dangerous?
Generally buzzing LED lights are not dangerous. It is just the clipping of the electrical sign wave that is not smooth due to a faulty capacitor or a low-quality globe.
The exception to this rule is if the buzzing noise is caused by an electrical arc that is tracking across a faulty hot joint or high resistance connection. Often you will see and smell smoke from a hot joint.
I tell all my clients that if you have a buzzing or flashing LED globe just replace it to be on the safe side.
Lights that flicker in people’s homes are a big distraction. They can cause headaches and prevent people from concentrating.
Often it is the LED light or globe that needs replacing. For downlights that have an external transformer or driver circuit, you could look at replacing that as well.
Most times the 12v downlights are user-replaceable as they just plug in and out. But occasionally they are hard-wired in so you will need an electrician to replace these safely.
Some people with really sensitive eyes can notice this flickering problem more than others. It is just the ways our eyes and brains react to high-frequency flashes of light. Rather than looking at the light globe directly to see the problem look at a reflected light pattern on a white wall. The flashes or strobe effect may be greater.
I am a qualified Industrial Electrician for the past 20 years and I love to share my knowledge on home repair jobs.
I love fast toys like Motorcycles, Cars, Jetskis, and Boats so writing about them is easy.
To keeps costs down I do all my own mods, repairs, and servicing. These skills I want to share with everyone. DIY is a skill everyone can learn.