Downstairs lighting circuit keeps tripping fuse - thoughts?

QTPie

Hi

We just completed on the purchase of a house. Big house, recently (past 4/5 years) extended and renovated. Lots of low voltage spotlights, but not insanely many (if that makes sense).

Haven't moved in yet (getting it redecorated), but was there this evening to talk to someone. After they left, I switched a number of the lights on (kitchen/breakfast, hallway, utility, living/play room - so most of the downstairs lights (but not all). Shortly after the fuse tripped and all the lights went out. I assumed that a bulb had blown somewhere, so went to flip the fuse back, but it wouldn't stay down. I had to go back and turn some lights off, before I could reset the fuse. I later turned the lights back on and - within about a minute - the fuse tripped again.

What is likely to be causing it? Any thoughts? Something simple/silly (before I speak to an electrician)?

Ebe_Scrooge

The most obvious cause would be a short within one of the light fittings - probably a wire either not securely screwed into the terminal, or else a stray bit of wire that's waving about and coming into contact with the casing of the fitting as it warms up.

The easiest thing is to try the lights one at a time - turn one on, leave it for a few minutes, see if it trips. If not, turn it off and turn the next one on. Repeat until you've isolated the dodgy light.

Then - TURN THE POWER OFF AT THE MAINS !!!! You only need to turn off the lighting circuit in question - but make sure you have indeed turned off the circuit you think you have. If you have any doubts at all, turn off the master switch to kill power to everything.

Then have a look inside the dodgy fitting. Check that all the wires are securely tightened into the terminals, make sure there are no stray bits of wire floating about, make sure there's no corrosion or anything inside. Also check that the bulb is seated securely in the holder.

Hopefully this will cure it, if not then it's safest to get a sparky to check it out for you. An alternative is to just replace that particular fitting, but that may not cure the problem if it turns out that it's not actually the fitting itself that's dodgy.

Anyhow, hope this helps.

spacey2012

You really need an electrician to test the board with a multifunction test and do the whole board and check earth tolerances.

Not the sort of equipment you have at home, given the investment and that it could go up in flames and many policies have small print about having electrics periodically tested, I would call a sparky to find the issue fix it and give you a electrical safety certificate.
The house may have been by the sounds had some DIY wiring that is not compliant.

Homely

This happened a few months ago to me and it turned out there was a pipe in the roof that had a slow leak and was dripping onto the wires, everytime this happened the fuse was go, obviously to protect things.

The plumber fixed the leak and it's all sorted out now. Definitely get someone to check yours out.

QTPie

Thanks very much both of you

Ok, got an electrician coming in tomorrow now.

The house had an electrical conformance certificate done about 4 years ago - all lights etc were fitted/checked by that electrician then (no DIY). Although since he managed to identify/record the cooker circuit incorrectly (he said 6mm, but it was only 4), I am beginning to have my doubts about his abilities...

QTPie

Thanks Homely - glad that you got your problem resolved