Light circuit advice please

[paulramplin]

Hi. I'm after some advice on what else I can try to stop my light circuit from tripping. The lights went out today when I was out (in other words, they didn't trip off because of something I did directly) and nothing I can do will stop them from tripping off.
I've opened up all the switches and can't see a fault there, and I've also removed all of the ceiling roses and can't see a fault there either.
A little background information: I have been decorating. This has involved removing switches - but not ceiling roses - so naturally I've looked there the most. But there seems to be no logical reason for it tripping.
Is there anything else I can look for?
Thanks in advance.
Paul.

 

[sparkwright]

Any outside lights filling up with water?

Is it a circuit breaker or RCD/RCBO thats tripping?

 

[sparkwright]

Decorating.

Could the wires at the light switch be 'pinched' against the back box/fixing screws or similar?

 

[crystal ball]

Nipped cable behind a switch sometimes hard to spot

 

[omega015]

Did the nuisance tripping only start after you had decorated? Switch off the circuit and carefully remove each faceplate one at a time checking for nipped wires, exposed conductors etc.. and replace and see how it goes.

Is it an RCD that's tripping?

 

[paulramplin]

To those that have asked - it's an RCD that's tripping.
I've looked in all of the switches and can't see any wires that might be at fault - but I'm gonna have another look in the morning when it's light, making sure to look for pinched wires or any that may have been nicked when I've screwed/unscrewed the switches.
Thanks for the tips.

 

[sparkwright]

Any outside lights filling up with water?

 

[paulramplin]

Some new information....
This morning, when the circuit trips off, it does it slightly differently. Previously, it had tripped off instantly, but now it takes about a second. Am I right in thinking this could suggest it's a damp problem and it's getting better because it's drying out?
(No external lights are damp at all that I can see, though.)

 

[jj4091]

If it did not do it before you removed the switches then I would think you are nipping a wire somewhere, either with a screw or behind the switch body,when you screw the face plate back on. Make sure all the wires are clear of both before you screw them back tightly. It might even be an idea to leave them with the screws just holding them in place & screw them back one at a time until you find out which one is causing the tripping.

 

[paulramplin]

Found it! It looks like it was a bit of dust in the earth terminal behind a switch. I removed the wires, took out the box and cleared everything out - there was a LOT of dust in there and I guess something must have got in when the switch was removed, causing it to short.
Thanks for everyone's help!

 

[ban-all-sheds]

Dust isn't usually conductive, and can't get into the switch internals from the rear.