Sitting room light won't turn off

Stephen93

Just ha a new combi boiler installed. They're running whatever they needed off the old immersion switch. Now for some reason my sitting room light is on (very dimly) when it's off and normal when it's on.

How or why is this? How can I resolve?

meercat

hard to tell what the exact issue is

The immersion and light circuit should be separate anyway so perhaps they damaged the cable during installation

an important note however is that your new boiler should not be connected to the immersion circuit

get the installer back and request an electrical certificate off them too.

Doolittle51

Could be a few reasons for this. A wiring fault or induced voltage from a nearby cable could cause it.

If a combi was installed, then I presume there is no immersion anymore? So they've probably repurposed the immersion circuit and should have installed a new fused connection unit, typically with a 3A fuse, but depends on the boiler specs.

Was the immersion used regularly before they installed the new boiler? If not, there's a chance that the issue already existed but was never noticed. If you turn off the circuit breaker for the boiler, does the problem go away?

Judging by the stippled ceiling, I'm guessing the house was built in the 80's or earlier, so unless it's been rewired, then there are all sorts of things that could cause the problem.

Antenna

It could perhaps be a coincidence the light issue occured after boiler work. Its not unknown with LEDs.

Are these lights on 2-way switching? (So can be switched from two light switches)

If so a long cable run between both switches could have significant capacitance between both switched wires (if side by side with no earth/neutral between them) allowing this to happen.

Were any bulbs on it changed recently? Changing a bulb could have made a difference to this happening or not.