LED bulbs on even when switched off at wall

[Sparkeng]

Hi all,

I recently bought and moved into a house and set about changing all the halogen bulbs with 4W non-dimmable LED bulbs. Upon doing so I discovered that when I switch the bathroom lights off at the wall, instead of going off they just become about half as bright as they are with the wall switch in the ON position.

I put the halogen bulbs back in and could see that they were all glowing very slightly, so there is definitely power leaking in somewhere but I have no idea how or where.

Below is my crude attempt at a wiring diagram for how the bathroom seems to be connected up.

Any and all suggestions would be greatly appreciated.

 

[Lucien Nunes]

This is in UK, yes? (Your connection suggests you are in France)
What type of switch is in use - an ordinary on/off mechanical one or something electronic?
Do you have any lights elsewhere in the house (esp. kitchen) that behave strangely, do not work, or do not light to full brightness?
If you remove one of the halogens, do the others glow brighter?

If the switch is electronic, it may be faulty, unsuitable or incorrectly configured. If it is a conventional switch that can only be on or off, then something is bypassing it as you suspected. It is quite common for LEDs to flash occasionally when a switch is off, powered by the miniscule leakage current between adjacent cable cores, but that kind of leakage is much too small to light a halogen lamp even very dimly. One source of enough current to make a halogen glow would be another lighting point incorrectly connected across the switch, hence my questions about anomalies elsewhere in the system.

 

[telectrix]

might help if we knew which bit of the UK. one of us may be close enough to you to investigate.

 

[Sparkeng]

I am in the UK, yes. In Dunfermline, Scotland.

The bathroom light switch (and all other light switches in the house) are simple mechanical switches.

Yes, of the 5 lights in the bathroom, the more of them are halogens, the dimmer the lights are with the switch in the OFF position.

I have tried removing the wall switch completely, and the lights still light up exactly as they would with the switch connected up and in the OFF position.

I have found no problems with any other part of the house's electrics, all other lights and all sockets work fine. However, for context, there is evidence that the previous owner did a lot of DIY, and very little of it is up to a good standard. So I am thinking the cause of this problem relates to an amateur attempt at wiring up the bathroom lights during a remodel.

Again, any advice is greatly appreciated.

 

[Lucien Nunes]

Your observations re. effects of removing switch and some of the lamps support the idea that a load of some sort, in the 10-100 watt range at a guess, is incorrectly wired with its neutral connection to the bathroom switched line. This can happen if the wrong black wires are connected at a junction box or rose. However, the errant load will only work with the bathroom lights off, or may not work at all.

Extractor fan? Does it work inc. any timer function?
Signs of removed low voltage lights for which the transformer(s) might still be in situ and (wrongly) connected?
Loft light that might be glowing unseen?

 

[Sparkeng]

There's no extractor fan, not sure what evidence of low voltage lights would look like, but haven't seen anything that I can imagine would constitute that, and I don't think there is any lighting in the loft.

Sorry, probably not very helpful, but that's the situation. If it makes any difference, all the lights in the kitchen are the same kind of recessed ceiling lights as the two ceiling lights in the bathroom. So I could imagine that the two bathroom lights have just been "looped in". Is there anything I can do, short of hiring a sparky, to find the source of this fault?

 

[dmxtothemax]

The most likely source of leakage is dimers or any type of electronic switch.
try isolating them one by one and see what happens.