Fuse Box Tripping Out

[Groupie]

Hello. Our mains fuse box keeps tripping out on the points switch. It will be ok for a while but trip out at intervals of anytime between 1 and maybe 12 hours. Seemingly for no reason,I have unplugged most of multi use areas ie computer,tv and outside shed but still the same trips when nothing major is on. Could the main box be at fault?
PS one thing odd is when I put the trip switch back on the washing machine lights up.and the local fuses in all connected things don’t blow.
Any help please so I could give an electrician some information

[The Builder]

Just need to be clear, Groupie.
I guess you mean an MCB (miniature circuit breaker)?
So it's the one for the "sockets" circuit - marked 32 A (32 Amps)?

[Groupie]

Yes 32A

[The Builder]

These things are an electrician's nightmare.
Because it's an MCB, then the fault is either overcurrent (overload) or short-circuit.

Intermittent faults are the worst to identify. It could be an appliance (kettle/washing machine etc).
I imagine the first thing an electrician would do (after checking all the obvious things) would be to measure the insulation resistance between Live and Neutral on that circuit.

That reading could tell him something.
A common fault is a loose connection somewhere. The resultant sparking can easily cause the MCB to operate.
Don't worry. He'll find it ;o)

[Groupie]

thanx for that info,watch this space for electrician results

[Groupie]

For 8 hours today all has been fine normal electrical usage then it tripped out and nothing was switched on at that time. Grrrr

[TonyV]

Not even the central heating?

[Groupie]

CH been on and off a normal through day but nothing physically switched on at the time the switch tripped.
All on as normal at this time,CH ,fridge ,freezer side lights ,tv and a computer.

[Hymie]

As The Builder says it could be anything – this happened twice to my mother, on the first occasion it was the kettle (easy to spot) on the second the immersion heater; a bit more difficult to diagnose as it was on a timer.

[Groupie]

Ok thanx all answers are helpful

[zebo]

Question for the experts, my oven caused the power circuit to 'blow' last week, the electrician who lives across the road kindly came over, fiddled with the consumer unit and reset it. He commented that according to a label on it it hadn't been serviced since 2009, is it usual to have them serviced? He wasn't touting for business, he was a very helpful neighbour who wouldn't take anything for his visit.