Brand new led ceiling light extremely dim as though not enough electricity Ask questions and find answers to many subjects relating to electrics and electrical work

[NickTEve]

I have just replaced a 16w 4 pin CFL ceiling light with a new led ceiling light and the new light is so dim that it is almost impossible to see any light. The old light didn’t work at all.

I thought that the CFL bulb had blown, so replaced it, but that didn’t work so I assumed that the light-fitting was broken and bought a new led light. Having fitted that there is clearly a trace of electricity, but it seems that there isn’t enough for the light to work properly. Is that possible?

The wiring is modern and the light is on the same circuit as another light that works perfectly well. The two lights are on a circuit with two light switches if that changes things somehow.

I may be able to get up into the roof above the wiring of the faulty light but it would be useful to know what I am looking for! Is there some sort of visible fault that could cause this?

Any help on what can cause this and/or what I should look for would be much appreciated!

[Mr White]

If the previous light did not work, and this new light does not work, the first thing to do would be to take the light down, put a flex and a plug on it, and plug it in to see does the light work.

[ericmark]

With any fault finding there are two methods.
1) Methodical work through the system until fault found.
2) Look at likely failure points first.
I would say likely failure point is the switches, with an LED lamp on a two way system there can be enough capacitive and inductive linking in the cables to cause the light to stay on dim even when switched off, so it is possible the light is simply not being switched on.

The same linking can also give false readings the neon screwdrivers and the like.

With a two way system the power goes through both switches, so if either fails the light stops working, there are two common ways to wire two way switching, the preferred method you have not counting the earth three wires at one switch and five wires at the other switch, if using that system [attachment=1]two-way-real.jpg[/attachment] then a link can be used to short out the switch so always on, which would show if switches are at fault.

However many DIY people get in a knot playing with two way switching, one take pictures before you start, and two ensure there is not power before playing, it may be better to get an electrician if not sure what you are doing.

If my guess is right, and only a guess, then likely it will need a load capacitor fitting in the lamp to stop it glowing, as well as curing the original fault [attachment=0]load-capacitor.jpg[/attachment] so may be better to get electrician to start with?