Why Do LED Light Glows When Off ?

Why Do LED Light Glows When Off ?

This is embarrassing if LED Light Glows when off. On advancement of lighting  technology LED lights have been improved manifolds and achieved reputation in the world market.  While there has been significant publicity, propaganda and discussions through writings, articles, and brochures with mentioning features, benefits, advantages and disadvantages of LED lights widely circulated and publicized both printing and electronics media in various ways. Even then, if the question arises Why LED light glows when switched off? which is absolutely surprising to everyone of LED lighting users.  

However, any good products might cause difficulties by any means. Because using any updated categories of products like LEDs, there can be some reasons involved with this. And no matter what that can find out and have the solution.  In view of the fact we shall try to address through this Article, which will help you to resolve the matter.    

Reasons – Why LED light glows when off?

While switching to LEDs or replacing a faulty LED lamp in some cases the LED continues to glow weakly after turning the light switch off. Whether this effect is the first time, the light switch is in the off position and the LED lamp continues to glow, that could be very surprising. As we experienced most of the cases the LEDs light up softly, but brightest intensity. Sometimes could be annoying if the luminaries is mounted in the bedrooms or offices and there may be the following reasons for this effect:

Low Quality of LED Bulb:

There are some low quality LED light bulbs available at a very less price, which was unfortunately produced by few manufacturers for temporary benefit. So that using this type of low quality bulb creates a lot of problems and the LEDs reputation is hampered badly. Quality of the LED bulb is the main reason, if any accident or choice you opted for a low quality bulb and this could be the reason that the bulb glows even after switched off.  

Storing Energy of LEDs:

Storing of energy may be the cause of LED light glows when off and the reason can be found in the LED light itself. If it has happened you can easily check this by removing the illuminant from the socket immediately after turning off the light switch. After removal, if the bulb continues to glow weakly, it may be due to the luminescent layer or the LED driver source. Nevertheless, if you find the lamp goes out immediately when it is removed from the socket, obviously the reason must be found in the electrical installation.

Radiant of Phosphor layer:

In order to produce white light usually blue light emitting diodes are used with an additional phosphor layer. It depends on the material of the semiconductor used, the luminescent layer can store a certain amount of energy in the form of visible light for a certain period of time.  In conformity with its wattage this leads to the afterglow effect from a few minutes or little moments. 

Switching System:

Switching systems could be detected as the other reason for the problem of LED light glows when off. While the neutral wire in the electric system is not appropriately earthed and sometimes causes very high resistance in the electrical wire, this may create some residual current and suddenly this current thus makes the LED glow even if the power system is off. Every so often, because of electromagnetic induction caused by the remaining current in the cables can result in the glowing of the LED even if the powering is off.

Electrical Installations:

Carelessness or inefficiency of electrical installation caused LED light glows when off. If you find the LED continues to glow permanently when the light switch is turned off, this may be due to the type of light switch or dimmer or an incorrectly connected switch. An unfavorable cable routing can be responsible for the glow when switched off. It usually happened after converting from old light bulbs to LED bulbs and any leakage currents and induced voltages were simply short-circuited by the filaments of the old light bulbs. Therefore these are enough to make an LED light glow weakly when switched off. 

LED Driver: 

We have to know what an LED driver is, actually LED bulbs and luminaries are equipped with an electronic circuit known as LED Driver. Frequently LED drivers generate the operating current needed  for the Light emitting Diode (LED). In electrical methods the drivers consist of various components including capacitors and inductors. Characteristics  of these components is to serve storage for electrical energy as well. 

It depends on the design of the driver circuit, these components may be active when the input voltage is switched off by pressing the light switch and the LED continues to light until the energy stores are discharged. Due to this technical reason, this can also take from a few seconds to several minutes to stop glows of lighting. 

Electronic dimmer:

Light glows when off due to the electronic dimmers (available in the marketplace) instead of convention dimmers with a rotary knob or push button. This dimmer you can control by pressing push buttons or even by touch easily. Whereas many of the electronic dimmers do not fulfill the requirement of proper specification for LED lights due to old aged incandescent and halogen lamps.

In fact, electronic dimmers need a minimum load of electricity for the correct function, whereas the economic design of LED light bulbs are different and able to function with AC LED drivers which are actually no minimum load transformers. In other words, LEDs have such a small electrical load that regular transformers do not register that they are wired to a bulb at all. However, if the load falls below the minimum load the electronic dimmer cannot switch off its output voltage completely even at the off position resulting LED continues to glow weakly.

Light switch with night light:   

There are some light switches that have an integrated night light, which ensures that the switch can be seen even in complete darkness. Usually older switches glow lamps used for this orientation light and often connected in series to the switched load. Without checking the load if  an LED connected with the integrated night light, that could be affected for the trouble of light glows. 

Due to the integrated power supply unit an LED lamp has a high resistance in contrast to incandescent bulbs or halogen lamps. The glow lamp may close the circuit due to serial of connection, even the switch is turned off. As a result low voltage drop is affected by the LED driver causing the light to glow up faintly.

Cable routing in Parallel:

Generally there are often two way parallel connections in the staircase and the long corridors of the house with a lot of switches are to be installed at different points to control the lights. Parallel cable routing over long distances is one of the disadvantages and cause of the problems. In this parallel cable routing, the voltage carrying conductor can persuade a voltage in the conductor separated from the light switch. For this reason there is a low voltage in the ceiling light even when it is switched off causes the LED to light up weekly.

How to Stop the Glowing when Switched Off?

In this article I have mentioned various causes that might happen in the section of the article captioned above (Reasons – Why LED light glows when off). Considering these causes I am going to tell you some of the Solutions which will give you relief from the problem. There is a saying, If you are able to solve your problem, then what is the need of worrying ? If you are not able to solve it then what is the use of worrying ? 

There are some Action of Remedies to solve the problem:

Action of Remedy- I : Replace the Bulb

There may be any problem in the bulb you have fixed or replaced with LED ones, so immediately replace another one and if it stops glowing after switched off then your action of remedy is successful. 

Action of Remedy – II : Earth the neutral wire

One of the reasons happened at the time of installation as the neutral wire is not earthed correctly. In that case contact an expert electrician, who is able to check the wiring and if it is detected the fault of earthing, so immediately fix it. While the wire is being appropriately earthed, you will witness the solution.

Action of Remedy – III : Installing a Zener Diode

This is usual because of the electromagnetic induction, which is caused by the residual voltage coming from the circuit and makes the afterglow of light. In order to protect this situation, you need to install a Zener diode as the virtual function of the Zener diode to regulate the voltage of the electricity circuit, while your glow LED is on. 

As such you could ask your electrician to set up a Zener diode which will block any residual voltage coming from the circuit. This is not a big deal to install for an electrician and the Zener diode is not very cost effective.

Action of Remedy – IV : Installing a bypass Capacitor 

Usually many of the times the wiring works was accomplished with two way connections, resulting voltage carrying conductor might sometimes induce its voltage into the other conductors along the way as normally some of the conductors are far away from the switch. In order to avoid such a situation a bypass capacitor is needed in the ceiling lights, which thus minimize the coming voltage being persuaded.  

Action of Remedy – V : Install a Neon Detector

Besides the capacitor, there is another option to install a Neon Detector, that can easily indicate AC and DC voltage and sub mode LCD display (maximum value for the reference). This device allows you to check the wires with a variety of home appliances through the circuit and to distinguish the zero-phase line to find the break-point.  

To protect the residual unwanted voltage, which makes the LED light glow even after the power supply is off, you can install the detector near the end of the fitting where there is the neutral earth wire etc. Neon detectors also work as indicators glow up due to the residual current instead of the lamps.

Action of Remedy – VI : Choose for LED Dimmers

In the perspective Dimmer is also an important factor, so you need to update the dimmer when you consider to change the bulbs. Old dimmer don’t work according to the required specification of LED lights, although the said old dimmer is able to function effectively for the halogen lamps. 

The regular dimmer is not matched and adequate with LED light as because these dimmers need some minimum amount of current for their functioning and due to the economic nature of LED light. So whereas the flow is very low, the dimmer will provide the output voltage even switched off. Therefore it causes LED light to glow.  In order to avoid any kind of hassle, it is suggested to replace the old dimmers with LED dimmers and then there would be no chance of glowing LED lights even after the power off.

Frequently Ask Question

Frequently Ask Questions

1. Why do my LED lights flash?

Usually people may think that overload of electrical power supply is the cause of LED lights flashing, but actually not, unless you reduce the wattage that the LED strips are drawing from the output and cause  constantly flashing. 

2. Is it usual that LED lights glow when off?

As we discussed in this article, there are a lot of manufacturers producing LEDs with lucrative but not qualitative, e.g. poor in quality and reduced price. If you purchase a good quality of LEDs these will not glow when off. If this happens, this is a problem with electrical circuit Not the Bulbs. There are some light switches through residual electricity even switched off.

3. Why does residual electricity come through?

While installing, the neutral wire in the circuit is not properly connected to the earth otherwise the earth wire is at too high a resistance, so resulting it creates a small current which is powering your bulbs. Due to electromagnetic induction a tiny pick up of electricity from cables running alongside each other. Now it is clearly understood that low level induction from the live wire causes the bulb to glow. 

4. Why do other bulbs not glow with residual electricity?

It has already been discussed that the diodes in your LED bulb can use the very low level of electricity to create light, which other bulbs are not able to do this. When light bulbs are installed with two way switches, within a while, glowing LEDs are particularly noticeable. Therefore, the same bulb is operated by two different light switches.

5. Why does my LED light turn off by itself?

LEDs are a special quality of light bulbs and if not an actual component in the LED will fail and will provide light for forever. Whereas the Fluorescent lamps and other traditional bulbs may burn out, while LEDs do not like these, they degrade and dim over time. LED light bulbs like 5A are absolutely a good lamp, which stay on, even at temperatures higher than those were the faulty lamp turned itself off.  Improper measuring circuit of temperature caused the lamp to turn off permanently. Also insufficient thermal conduction from the LEDs to the heat go under the surface.

Bottom Line

Every good product might have bad  problems but also have good solutions too. Therefore, we have elaborately discussed in this article about the reasons ‘why do LED light glows when switched off’ and the action of remedies, e.g. solution of this problem. If you properly scanned and concentrated properly, I hope it would provide you enlighten your knowledge and ideas concerning both reasons and solutions. 

Notwithstanding, further to draw your attention on this regard, if the issue is caused by the illuminate itself it is not at all a general problem, whether the fragile light is worrying you then the only solution is to replace the LED lamp with a different type on an immediate effect. 

Finally, LED light glows when off is liable for the major cause indicated as electrical installation, which not only dilemma but also affected lifespan. Therefore, fault in the electrical installation should always be corrected by an expert electrician or any specialist consultant.  

you can read also: Why do led lights flicker?

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