LED striplights won't switch off completely if fitted on wall, but will do when not fitted ...

[Icicle19]

I've purchased Lepro 15m LED strip lights - product code PR410047-RGB-UK, and have fitted them at the top of the walls in my daughter's bedroom, where the walls meet the ceiling. Although listed as 15m long, they are actually two strips of 7.5m each, running in parallel adjacent to each other up the corner (about 1m distance) to the top of the corner wall/ceiling interface, and then each strip goes off in the opposite direction to go around the whole room. They are powered from the supplied adaptor plugged into a standard UK wall socket, and there's a small control box with a receiver on it that both strips of lights plug into. It's all supplied as part of the package.

I've found that the strip lights don't turn off properly. When you select 'off' on the remote, it looks like they turn off, but actually they're not off, they still emit a fainter pale whitish light that is easily noticeable at night or in a darkened room. So they're clearly still 'on' to some degree and drawing power. The only way to switch them truly 'off' is to switch off at the power socket on the wall, only then do they really switch off and go completely dark.

When I discovered this, I took the lights down and replaced them with a second identical Lepro set, having tested the second set quickly in the dark to make sure that they did indeed turn off properly. All was good in the test, so I've put them up on the wall around the room............only to find that they too now don't turn off properly. It's exactly the same issue as the first set of lights. Swapping the control box, power adapter and wall socket they're plugged in to makes no difference, they still don't turn off properly unless switched off at the power switch. But they tested ok when not fitted around the room. And similarly, the first set of lights I've taken down now tests ok now that they're no longer fitted around the room.

So, bizarre as it seems, it looks like it's something to do with the location of strips. When not fitted at the top of the wall, and tested in the dark simply laid on the bed, they do go properly off with the remote. But fitted around the top of the walls around the room, they don't properly go off with the remote.

There are no power wires around the top of the room, only a central ceiling light. As it's a relatively recent house (20 years old) the plasterboard for the walls is fitted to a metal framework, and although I can vaguely recall stuff from school about moving magnets in a coil generating electrical current etc there's nothing like that going on here that I can work out !

So I'm baffled.......part of me thinks the answer must be obvious, but I'm not seeing it.........would appreciate any advice and guidance, thank you.

 

[marconi]

Is you home fed by an overhead cable? If yes does the cable run parallel to where the strip lights have been fixed?

Do you live close to any radio transmitters (radio, TV, mobile phone) or high voltage lines?

When the tape is removed from the back of the strip so it can be stuck to the wall does it expose metal tracks which come into contact the wall?

Please send me a picture of the three connectors at the end of the wires emerging from the control box.

 

[marconi]

Are your connectors like these? I have in mind a cheap solution which I could make and send to you. Beforehand I need to send you three resistors so that we can safely test the solution first. Please private message me and we can exchange details.

RGB LED Strip Gapless Connector - https://www.ledsupply.com/accessories/rgb-4-pin-led-strip-gapless-connector

Does your consumer unit have an RCD like this in it? It will have a test button on it.

80 Amp 30mA 2 Pole RCD Type AC - BG | BG (CUR8030-01) - https://www.tlc-direct.co.uk/Products/BGR8030.html?source=adwords&ad_position=&ad_id=&placement=&kw=&network=x&matchtype=&ad_type=pla&product_id=BGR8030&product_partition_id=&campaign=shopping_switchgear_distribution&version=finalurl_v3&gclid=EAIaIQobChMIzaHOmfja-gIVxu7tCh2MXAU9EAQYAiABEgI3tPD_BwE

please buy a volt stick pen and check along the wall where you affix the led tapes. The lap one would be good enough. Let me know what you find. The volt stick should not light up.

Voltage Testers | Electrical Testers | NoLinkingToThis - https://www.NoLinkingToThis/c/tools/voltage-testers/cat7910007

 

[Icicle19]

Many thanks for your replies. Re your questions -
- home is not fed by an overhead cable, all services are underground and the bedroom is on the upper floor.

• no nearby transmitters or HV lines
• the only close thing is a TV aerial in the loft above one corner of the room, plus the co-ax cable associated with that.
• the back of the LED strip does not have any metal tracks exposed, it's just plain adhesive backing, no electronics on the sticky side.
• picture of the control box and connectors attached. The black tipped stem is the receiver from the remote.
• connectors are similar, please see photos
• consumer unit does have an RCD covering both sockets 'ring mains', please see photo attached
• I dug out my volt stick pen, when the LED power supply is switched off at the switch on the socket, there is no voltage detected along the LED strip around the room. When the switch to the power supply is on, and irrespective of whether or not the LED lights are lit or not, voltage is detected in the white control box, the leads from the control box to the two strips, and all along the strips at the top of the wall around the room, and the strips glow faintly in the dark as described in the original post above.

After a bit of googling the only vaguely helpful info I could find was at these two sites-

David Savery Electrical Services Ltd. - Why do my LED bulbs glow when off?

How to fix LED lamps that glow when switched off.

www.davidsavery.com

Ceiling LED light emits very dim light when switch is off!

I have overhead ceiling LED light fixtures. When I turn on Main Switch of the house, I see the LED starts emitting very dim light ( have to look for a 3-4 second to perceive) even when LED's switc...

electronics.stackexchange.com

but as these are concerned with LED bulbs and not striplights I don't know how much is relevant to my issue.........

Not sure if any of these answers help much ?

 

[marconi]

I will study tomorrow And respond.

 

[marconi]

Thank you. Good morning. The voltstick test was a check to make sure that the wall itself, or rather the metal backing or framework, was not connected to the mains by some fault in your home's wiring.

What is happening is similar I think to what is mentioned in the references you looked up. If you take a look at my electrical art I have sketched out the installation. When the strip LEDs are off the three switches in the controller are open. They are semiconductor switches and even when off may leak through them a very small current but if this was causing the lights to glow then it would not require them to be attached to the wall.

The fact that the glow only happens when affixed to the metal backed plaster board indicates some capacitive effect formed by the proximity of the strip to the plaster layer and the metal back and metal support structure. Thus even when the controller is off, there is a path for current to flow through the +12V wire through a diode, the capacitance and then to earth. The shear size and extent of the fabric of your home means it is connected to earth through being on it. The mains supply has the neutral connected to earth. The adapter also has some capacitance between the 240V ac mains side of the transformer and the safe 12V side. There is then a complete circuit for a small leakage current to flow sufficient to cause the LEDs to glow dimly.

The solution is to divert this leakage current away from the RGB diodes using three resistors R connected between the +12V line and each R, G and B line. When the controller is turned on it has sufficient current capacity to power both the LEDs and the small current through the three resistors R so it not bothered they are there.

Do you want me to make up the connector with three resistors or would you like to do that yourself? I can send you the resistors of which I have hundreds in my den. Do you have a small soldering iron and solder?

 

[Icicle19]

Thank you. I've attached a pic of how I think the metal framework for the partition wall is. I don't think the plasterboard has a metal back, it's just plain ordinary cheap plasterboard, with a paper outer covering on both sides. But I'm guessing, from your explanation, the proximity to the metal framework is still enough to induce a small current to flow.

I've printed off your diagram, thank you, and sort of follow it but am not good with electronics, so if your offer to make up the connector with resistors still stands then please can I take you up on it ? I'll send you a test personal message to check comms, and we can further discuss there ?

Many thanks.

 

[marconi]

The connectors arrived today. I will make up a test one tomorrow to post to you on Monday.

 

[marconi]

For those that might be following this thread here is some recent history with a report by the OP:

Hi, they arrived today, thank you, and I tried them tonight. I put them on the free ends of the two striplights (see slightly blurry pic below), ensuring that the end of the strip was fed into the end slot of the connector so a contact was made between the four gold terminals on the strip (i.e. at the cut marks on the strips) and the four terminals in the connector. The gold terminals slid underneath the connector terminals, with the +ve symbol on the connector plastic body aligning with the 12V +ve gold terminal on the strip. Unfortunately neither connector made a difference........the striplight is still glowing faintly when 'off' with the remote and with the wall switch to the power adapter on. Both strips still light up as they should do when 'instructed' by the remote.

I'm pretty sure I fitted the connectors ok, though I now realise I didn't try them individually ie both were on the strips when I was testing, but that wouldn't have mattered would it?

I don't know if this is relevant, but we haven't been using the striplights since fitting them, so before trying the connectors I plugged the power adapter in to the socket and lit the strips, then switched them off with the remote to check they still glowed faintly. The first time I did this most of the LEDS in the strip did actually go 'off' and couldn't be seen, but a handful went blue, and somewhat brighter than the faint glow I described earlier. I turned then off with the remote, and on and off again several times but I couldn't get that to repeat, they all simply glowed faintly as described before.

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[marconi]

I have just posted you some nails, connectors and thin wire. Please see the attached amended electrical art below. The nail (top right in red) is driven through the plaster until it makes contact with the metal structure behind. The nail, and thus the metal structure behind is then linked to the three resistors with the white wire. The connection is made to the white wire where the three resistors join it. The connector is then put on the end of the LED strip as before. Now try out the lights and check if they glow when plugged in and switched on at the socket but turned off on the controller.

It may be necessary to connect the horizontal metal structure to the vertical structure behind the stretch of led lights by driving in two nails and linking them together - see bottom left.


All this is perfectly safe to do. What it aims to achieve is the the equalization of potential between the metal structure and the wires of the LED strip so that there is no longer an alternating mains electric field causing current flows through the strip LEDs especially the red ones which have a lower forward voltage to illuminate.