LED After-Glow?

Florescent lights even on single switc keep glowing or flickering; not all but one or another in each house,even with all new wiring and fittings.

It really needs more research.

But in case of LEDs it is not hi-voltage and galvanically isolated from mains?

Max length for a LED feeder run is not more than 30m. Put a twist in the feeder wire and it should eliminate the after glow. Keep the light circuit for the LED seperated from any other lighting circuit.

Run all LED's on a twsited pair of wires. It will solve the issue.

Genite Centurion boet. Vaat n dop vir my asebleif.

IQ

You might want to check the switches for the lights in question to make sure the "hot" lead is being switched and not the "neutral" (white).

This is what I may have to do, but was hoping not to have to pull up the floor upstairs!.

70s wiring in the UK feeds the lighting ring (L,N,E) to a junction box under the upstairs floor, then switching lines (L,switchedL,E) down to the switches and another set (switchedL,N,E) to the light fitting.

I think you are saying there is always a slight glow to these bulbs when the power is off, but if you are seeing them "glow" for a short time (or maybe even up to a few minutes) after being switched off, there may not be anything wrong. I've seen quite a few high-brightness white LED's that will continue to glow after power has been removed. It's a bit of persistence with the phosphors that are used to turn the blue LED light into white light.

Just wanted to be sure we're clear on what you are seeing.

Tom D.

This glow is visible all day, except on the sunniest - few and far between at this time of year!

I would disconnect the wires at the lights and test for voltage...You may not be properly grounded....Check to see if your main panel has a ground wire leading directly to a ground(dedicated ground), not just an incoming neutral...video for installing ground rod=

http://www.diynetwork.com/videos/installing-a-grounding-rod-video/19425.html

Replace your switches. They may have been oxidized. Carbon can pass small current.

Three way switches can be the issue. Try turning off from one location and if instantanous, should be OK. If at the other, glow issue remains, most probable just that switch. If at both switches glow remain issue, still think your problem is the switches.

Unless your kitchen lighting is an embodiment of Tesla's dream of wireless electric power for everything, current to light the LED's is coming from the branch circuit that powers your kitchen lights. To check it quickly, turn the branch circuit off, then disconnect the ungrounded (not-white, not-green) supply wire to the switch, then restore power by turning the circuit breaker back on. If there is no light from the LED's, that switch is defective. Replace it.

If this is a 3-way circuit, and if there is still light from the LED's, turn orr the electricity at the circuit breaker panel, re-connect the switch you tested, and follow the same procedure with the other switch. If you are using a dimmer or some other kind of electronic switch, anough power may be leaking through the solid-state switching element to light the LED's. This is usually a triac, but is sometimes a pair of SCR's hooked back-to-back in older devices. The cure is replacement. Enough current may be passing through it to light LED's but not to produce a noticeable glow in filament lamps.

If the quartz-halogen bulbs in your fixture were connected through a "soft start" device that slowly increased turn-on voltage to reduce thermal stress on the filaments and thereby extend bulb life, it should be disconnected or bypassed. LED's have no filaments, so they don't care.

Unfortunately, Tesla's dream is too dim to see by;-( Standard 2-way switches used, same result whether switches are both off, or both on.

By any chance are either or both of the switches the type that have an indicator light in them (so you can see them in the dark)? Some manufacturers of these types of switches actually used a small current through the filament of the lamp (or other load) to drive the indicator. This small current could be what you are seeing.

Tom D.

The first thing I would do is perform a politary test on the circuit to make sure A N & E arer all in the appropriate terminals sounds like some 1 might have stuffed up with terminals typical of unqualified handyman wireing maybe a N & E transposed in circuit

I have 3 of these over the garage door, two are ok the third stays with the after glow, I keep meaning to check the wiring to see if the live neutral connections are reversed, it's been 3 years since I spotted it so now I have a reason to check it.

Bazzer

Before you rumpage throught the wiring of your home a question: Did you use identical LED clusters for all rooms? There are differences in the electronics inside the LED clusters. Some use a rectifier bridge and a large electrolytic capacitor to smoothen the 12V AC supply coming from an original Halogen lamp related either iron or "electronic transformer". Others do not use the capacitor as especially when the mains frequency is at 60Hz a flicker would not be really visible. At higher frequencies from electronic trafos this is anyway not the case. But the makers don't know the application - so most have the (smaller or bigger) capacitor.

Some clusters use for cost and performance reasons already LEDs as AC to DC rectifiers in this constellation. The trick is that the "LED bridge rectifier" will already produce light output - what is not the case for the standard 4 diode bridge rectifier. If you turn off the light and the smoothing capacitor is fully charged 2 LEDs will consume the current out of the capacitor. In my cluster this was really visible as only 2 of the 30 or so LEDs showed the "after glow". But this glowing due to the current flow reduces with decreasing available voltage through the LED and it gets dimmer and dimmer but it will take time until the LED light is really invisible. (depends on the quality & size of the capacitor! This is also due to the semiconductor effects of an LED when supplied from electricity stored in a capacitor. The current decrease is non linear.)

So the question is: are the LEDs still glowing after 5 to 10 min or so in "off" status - this was about the time I observed with such an LED cluster in my own kitchen - or still carrying on to emitt brighter light. As there are also phospor coatings involved when making LEDs with warm light output the small glow due to the electric issues will be "amplified" and causes still a brighter light output.

So I would simply take the LED luster and exchange it with one which did not show the effect and test this. If the "effect" moves with the cluster no need to look into the wiring of the house. I personally decided to ignore the after glow effect after I know why....

UK, so 220V, 50Hz. The LEDs were bought as a pack of 10, so no suggestion of different components used to make them. They are still glowing 3hrs after they were switched off this morning.

Hi,

You mentioned 2 switches. I believe that your kitchen light is controlled by a "Stair case wiring", with two SPDT switches with the live wire connected to the pole (Common) of one switch and one terminal of the LED connected to the pole of the other switch. Since the wires connecting the switches are in parallel with each other and placed close together, the pair acts like a capacitor. The capacitance reactance of the two wires, a few hundred K ohms, will be enough to pass enough current through the LED to make it glow.

Check the voltage at the light socket with a meter when switched off.Perhaps the 3 Way switches were wired improperly.If so, when in one position, there will be two "hot wires" connected to the socket, and the other way two "Neutral wires will be connected.On an incandescent lamp, it will still appear to work properly, but with LED's there could be a problem with residual leakage.The neutral should not be broken by the switch, only the hot wire.The neutral should be tied to the other neutrals in the J box.

I am betting on one of the switches having a neutral wire switched, this would give a voltage from neutral to neutral when off, or hot to hot when off, creating a small differential voltage/current.

Very little current needed to power LED's.

An easy way to trace the wires from switch to switch is to power the circuit off, and use a 9volt battery to energize the wires at one switch, and then measure at the other end to determine proper wiring.

The LED itself shouldn't be the problem. Afterall, the bulb is basically a 220 V, 50hz device. A voltage reading at the hot terminal to ground should tell you if you have a voltage leak or not.

UK version

A good presentation.

This is a common problem I've found with several varieties of LED (all around 1.3W). At two separate house both one 10 years old and the other is 2 years old. All the switches are brand new. There seems to be enough power bleeding through the switch to allow them to glow but not a cfl or other types.

Weird. There almost like night lights.

I cannot explain why your LED's glow when switched off.

But Zodiac at post 15 touches on a possible explanation because I have had a problem with 2-way switching on a staircase whereby tungsten lamps kept failing at the moment when switched on.

Some after only a few hours or at best a few days. I partly solved the problem by using a low wattage bulb (for economy) and left it switched on most of the time. But they still blew when switched on.

I guessed at the time it had something to do with long cable runs and capacitance and voltage. Other bulbs in the house did not blow. They ran for months or years.

I tried connecting a thermistor in the circuit but the bulb still blew - mainly because I had trouble getting an exact match between bulb and thermistor I think. Then I tried an electronic 2-way dimmer switch. With much more success by keeping the light dimmed a little.

So far so good - the bulbs have stopped blowing.

The easiest way to tell if the parallel wires are transferring energy is to set both switches "in-between" neither on nor off.

AC voltage will be off of both wires between the switches.

If they still glow after that, then your problem is elsewhere.

Not possible with UK spec switches - they are spring-loaded to be either position 1 or position 2 with minimum transition time, to avoid arcing.

Which spec you are referring to.

All light switches are everywhere in the world are:

Toggle in DC applications [may be used in AC also are more safe as you indicated]

Only Slide or rotary switch may have that problem if their format is

make-before-break.

Or the switch has got faulty and sticky in its toggle-action.

Is it not run on a DC supply?

Or run through digically controlled circuit having no isolation step-down transformer.

Supply is 220V, 50Hz a.c. The'bulb' has all the necessary electronics inside.

Thanks.

It may be in this case possible to flicker or glow.

Update:

I switched off the lighting circuit (Glow vanished), removed the clusters & tested for ground leaks/continuity/etc.

Replaced clusters and turned on supply - no glow!, that is until the switch has been on, then it returns.

Obviously something to do with the internal wiring of the clusters.

Oh well; grab a single malt, sit back and relax.

You have to make up your mind. The ones in the bedroom doesn't glow, how can the internal circuit have something to do with the glow?
And the one in the kitchen...does it glow the whole day?...or till only 3 hours after the power was switched off?

See my latest post on after glow of LED's. I am researching this and seeking fiurther input

Solution is a simple twsit in the feeder wires before connecting to the driver, if a driver is used.

IQ