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Why LED Light Glow Stays On Dim When Switched Off ?

April 20, 2023

Did you notice led lights glowing when off? You are none of many users experiencing this problem. This issue is prevalent and not harmful. However, it will also cause certain discomfort.

Fortunately, there are ways for you to fix the problem of the LED lighting up even when the switch is off. Do not skip any information. The instructions below will tell you how to stop LED lights glowing when off.

Why Do LED Light Stays On Dim When Switch Is Off?

LED lights that glow even when turned off are quite common. People even gave this issue a name: ghosting.

Is it dangerous for LED lights to glow when off? In general, this phenomenon is harmless to led lights or led lamp in particula. It just annoys some users, especially when you install lights in the bedroom.

The fact that the light stays on when turned off also slightly affects the amount of energy, electricity consumed. Then, glowing may not cause any serious problems but it could “hurt” your home electricity bill sometimes 😊.

There are quite a few reasons for this phenomenon. The problem may lie in the circuit, the bulb, the electrical wiring. installation.

Caused by the electrical circuit

Electrical Circuit could be a reason for glowing led light
Electrical Circuit could be a reason

When LED lights glow when off, you should care about the electrical wiring system, power supply or the led driver. The circuit’s external and internal factors greatly affect an LED light’s performance.

Neutral wire unconnected to Earth

Along with the ground wire, LED lights’ neutral wire help to stabilize the voltage, creating conditions for the power to pass to the lighting equipment.

Neutral wire unconnected to Earth may led to led staying on dim
Unconnected neutral wire may establish unstable electrical current

Within the electrical wiring, the neutral wire establishes a path for the current to return to the power source. Thanks to the grounded neutral wire, the accumulation phenomenon and charge leakage will be eliminated.

In contrast, when the neutral wire is not grounded or “floating neutral”, leakage current will make an LED light stays on dim when switch is off, causing afterglow.

An electromagnetic induction

When the power path generates an undesired electrical signal or an external electricity source affects the led driver circuit, electromagnetic interference occurs.

These signals will cause transmission disturbances. At its strongest, EMI can even cause afterglow in LED lamp.

LED driver

Driver playing a main role in establishing a stable electricity current for LED Lamps
Driver playing a main role in establishing a stable electricity current for LED Lamps

The LED driver is the indispensable electronic circuit of the LED bulbs. The driver consists of two main components, a capacitor, and an inductor, responsible as an energy store, generating the necessary electricity current for the lamp.

Control circuit also known as LED Driver has unique design that allow capacitors and inductors to operate even if you turn off the input voltage. Only when switched off the energy stored in them will the LED stop lighting.

The mechanism for discharge the capacitor’s energy, and inductor will depend on the control circuit design. Usually, this process takes only a few seconds. But in some special cases, it can last for several minutes.

Caused by LED bulb

LED Bulbs themselves are reasons for Glowing
LED Bulbs themselves are reasons for Glowing

In addition to the electrical wiring or driver circuit, the cause of the problem may also lie in the light bulb itself. Your led lights can face two main problems: excess energy storage phosphorus and poor bulb quality.

Low-quality LED bulb

The phenomenon of lights glow when switched off occurs most often on LED bulbs of poor quality.

Low-quality Bulbs possibly cause led lights glowing when off
Low-quality Bulbs possibly cause led lights glowing when off

LEDs that do not meet factory standards are prone to electromagnetic interference, unable to establish a stable electricity current or do not receive a stable power supply. As a result, the afterglow occurs, or even flickering led lights when the power is off.

Luminescent Phosphor Layer

The white light of LED lights are usually produced by combining a light-emitting diode with a phosphor layer. This coating will absorb blue wavelength light, thereby making the desired light.

In addition to the ability to absorb light, the phosphor layer of LEDs can also absorb energy. It cannot store energy for long periods. But some types of luminescent layers can dimly glow even when the power is turned off. The phenomenon of the lamp glowing due to the phosphor layer of LEDs does not occur often.

Because for the coating to generate electrical energy, it needs to combine with a good semiconductor material. An LED bulb glow effect due to phosphorus layer is also usually short-lived.

Caused by electrical installation

Caused by electrical installation
Caused by electrical installation

Along with the power source, the electrical istallation including the light bulbs, the circuitry, switch models can also be the reason why do LED bulbs glow dimly or widely known as the afterglow effect.

You may also care: Led light not working but has power

Electronic dimmers

Electronic dimmers do not meet the latest LEDs specifications
Electronic dimmers do not meet the latest LEDs specifications

An electronic dimmer also known as normal switch lets you adjust the light with just a push or touch. This adjustment method is less optimal than rotary or push regulators.

Also, electronic dimmers are quite old, working for halogen only and do not meet the latest LEDs specifications. In specific cases when using this old model one for LEDs may cause the light switch buzzing and possible dangerous consequences!

Or the dimmer may need a minimum load to work properly. And when the load drops to the minimum, the dimmer won’t be able to turn off the lamp’s output voltage completely. LEDs not achieving that minimum load stays dim when off with low light.

Light switch with night light functions

Night light switch may lead to glowing effect of led lights

The integrated switch with night light is an innovation that brings many conveniences. Even in completely low light, you can still detect the switch.

The problem only appears when the built-in afterglow lamp is connected in series with the switched-off LED ceiling light load.

Thanks to the power supply, an LED lamp has a high resistance. The indicator light glow connected in series with the LED, causing a voltage drop. As a result, LED lights may still glowing, stay on dim when the switch is off.

Neutral conductors switch

The principle when wiring is to let the single-pole light switch phase in the line. If this principle is not followed, the L phase will not be converted, instead the neutral wire.

When this happens, the capacitive and inductive effects will still work. The voltage generated between the live phase and the neutral wire will be strong enough to cause LED lights to glow weakly.

Conductors of two-way voltage

Two-way voltage conductor is often used on long corridors and stairs. In these locations, a two-way connection makes it possible to install switches at various points, making it simpler to control the lights.

But this type of connection leads to a big problem: long parallel cable routing. The conductor will generate voltage and separate this from the switch.

When the power switched off, a small amount of voltage may still be present in the lamp, producing afterglow phenomenon.

Indicator light

The socket panels of LEDs have an indicator light that needs the energy to light up in all cases. Due to the same wiring, the LED can draw power from the indicator lights.

How to stop LED lights stay when turn off

Guidance on how to stop led lights glow when off
Guidance on how to stop led lights glow when off

The reason for the LED lights glow when when switched off is quite a lot. So is there any way to stop led lights glowing? Here are some methods you can refer to. They are both quite effective and very simple to implement.

Replace a new light bulb

Replace new led bulbs to stop led lights afterglow effect

Well the very first solution crossing my mind if I had to face with the afterglow effect would be replace a well-qualified LED bulbs.

We highly recommend you buy products from a reputable manufacturer on the market to completely stop led lights glowing.

Should use CFL

As you have seen, the excess voltage in the circuit is the main reason why do LED glow when switched off.

And to stop led lights glowing, you can try to install CFL (Compact Fluorescent Lamp) into the led driver circuit. If CFLs are not available, you can try using incandescent lamp.

Comact fluorescent bulbs are quite an energy efficient. It will absorb voltage in wiring and switches.

In general, this method is only a temporary solution. Because you do not thoroughly handle the problem that the lights, wires, or power supply encounter.

It is better to consult with people who have experience in this field before setting up any electrical installation.

Make sure the CFL is compatible with most of your fixtures, wiring, and driver. In addition, when installing the lights, you need to turn off the main power supply line for safety.

Make sure wiring in good condition

Cable arrangements, connection between wires that are too tight or have two-way voltage conductor installed in the wrong place can cause problems.

If you haven’t done any wiring repair work before, it’s better to consult an electrician. They will conduct system checks, learn about the problem and have a method of handling if the line is down.

Install a neon indicator

Compared with LED lights, neon lights give a more stable light.

If the LED is directly affected by the residual voltage and capacitance in the circuit, a neon indicator is the opposite. Neon does not include any electronic components and acts as a voltage immersion device. A neon indicator will only light up if the residual current causes a problem. Therefore, when the light is off, your LED will no longer light up annoyingly.

You can find neon indicator at very low prices. Or you can also look for old indicator lights in damaged electronics such as blenders, kettles, and refrigerators.

To install the neon indicator, all you need to do is just insert it between the neutral wire and the wire. Don’t forget to check the voltage range to avoid burning the device.

Install Zener diode

Usage of zener diode could be a wise choice for problem
Usage of zener diode could be a wise choice for problem

If grounding wiring is the main reason why your LED is always on, you can stop led lights glowing by using a zener diode.

This device will alter your current, thereby correcting errors in the grounding wiring. It works on the principle of voltage regulation, thereby blocking all charges.

You can find zener diodes at most electronics stores. You can also install this type of diode yourself without the need for an electrician.

Try different dimmers

Using modern dimmers to stop annoying glowing lights when switch is off
Using modern dimmers to stop annoying glowing lights when switch is off

Old dimmers, casual light switch requiring a minimum load to work properly, will no longer be suitable for current LEDs. If you’re still using a regulator design dimmer for older halogen lights, you’ll need to update the old dimmer one.

Once you replace the appropriate dimmer, the LED glow when you’ve turned it off will no longer bother you.

Install extra capacitors

Conductor connected in parallel carry a voltage that will trigger an afterglow effect in the LEDs.

Removing this phenomenon is very simple. You will just need to add more capacitors to the lights. These capacitors will suppress the voltage drop. Flashing or glowing bulbs will also no longer occur.

In conclusion

Light staying on dim when switch is off is a fairly common problem. There are many causes for this problem, for example, the neutral wire in the circuit is not connected, electromagnetic induction causes an electric current or maybe the led light stores energy thanks to the luminescent layer glowing phenomenon.

To put an end to this annoying phenomenon, you can try installing some additional devices such as CFLs, neon indicators and capacitors. Or just by checking the wires and power supply, you can also spot the problem and get the right solution.

The last piece of advice Emberlight want to recommend is not to forget the safety measures when installing CFLs, indicator lights, or diodes fast. And please keep in mind, any issues related to the electrical installation should be examined by professionals only.

Lexii is a marketing creative with 6 years in Event, Product, and Social media marketing. She has assisted with coordinating and managing marketing campaigns for Procter & Gamble, and assisted with growth of smaller CPG brands on a national level.

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