LED lights dim when switched off

[pigshed599]

Hi,

Had a strange problem when I swopped some 50w GU10 bulbs for some 21 LED 1.2w ones. When the power is switched off to the light, the LED bulbs still glow (albeit very dimly)!
I then checked the voltage when the power is off at the light and i have 5 volts showing, which is obviously enough to make the LED's glow very slightly.
I then checked other light circuits in the house and some have the 5volts showing, other circuits show 0v.
Any thoughts on this? I have not had time yet to investigate further but I am thinking broken neutral/faulty rose/switch?

Thanks.

 

[Mark.W]

Borrowed Neutral maybe? Been a lot of threads on this topic lately!

 

[pigshed599]

Have been reading up on the borrowed neutral threads, can this condition only happen if you have two seperate light circuits from the fuse box (i.e. up & down)?

This house has all the lights on one ring.

Thanks

 

[quince80]

sorry mate what do you mean? are the lights wired as a ring then?

 

[pigshed599]

Sorry I meant all light circuits are fed from 1 MCB, so was wondering if in this situation can you have a 'borrowed neutral'?

Would a 'borrowed neutral' need some cross over between seperate circuits, like a link between the upstairs light circuit and the downstairs light circuit?

If this is the case, any ideas where the 5 volts is coming from?

 

[quince80]

how i understand it, it doesn't have to be an up and down circuit. the 'borrowed neutral' is just more common in a house having a separate lighting circuit for up and down stairs. you say there is only one lighting circuit? so i can't think why you would have a borrowed neutral in that case. i have heard of a thing called a 'back feed on a neutral' but if i'm honest never really looked into it. the neutral bar is a common point for all your other circuits so if you isolate the other circuits one by one and see when the led goes out, you may be able to eliminate problem by trial and error but just do it safely. i hope this helps you a little mate.

 

[pigshed599]

Thanks, I will have a look at that.

 

[Yooj]

Are you getting the 5 v across N-E, if so, you might need to look at your earth connections.
If you have a wander lead, check Neutral on suspect lighting circuit to neutral and then earth on another circuit, and then do the same for the earth on the lighting circuit.

This should help to identify where the 5v is...i.e. on the N or the E.

Yooj

 

[pigshed599]

Thanks, I am going to have a good look at this tomorrow and will do as you have suggested.

 

[BEN5637]

hey mate, are the lights on a 2-way switch

 

[pigshed599]

Finally found the cause of this, it turned out to be an old lighting rose that was hidden above a lowered ceiling, there wasn't any fault with the way it was wired up, but I found the rose cover was completely full of dust/dirt that had fallen through from the loft and this was conducting between the terminals!

Simple cause but it took some time to find!

Thanks for all replies.