mystery tripping switch

[Thermo]

For some reason on odd occasions the main trip switch on our circuit board trips during the night or early morning. There seems to be no pattern to it at all. None of the circuit breakers to the individual circuits are tripping to indicate which circuit it is, and as its during the night we arent overloading the system. Could it be a surge of some kind in the actual supply coming into the house or something more obvious?

many thanks

Thermo

 

[Jaymack]

Is your main trip switch, a main RCD on a TT installation?

 

[Thermo]

its a 100 amp contactum board. it has two breakers for the lights and then splits to an 80 amp rccb for the rest of the circuits. Its the 100 amp switch that is tripping. The whole board is fed dirct from the meter tails.
Dont know if that answers your question, but if you need anymore info ill do what i can to find out!

 

[Jaymack]

I would question whether a 100A main switch would trip, without a CB tripping downstream of this; and without showing signs of local damage on the distribution board etc.
Is it possible to post all the details of the unit which is tripping, these are listed on the unit itself; or a picture on imageshack?
This fault is indicative of a trip under earth fault conditions; whether RCD or ELCB; do you have an economy 7 supply which is switching in at night?

 

[RF Lighting]

Do you know if it trips at the same time every night or does it vary? I think it is unlikely to be surging / spikes in the supply as this would tend to just happen as a one off rater than every night.

 

[supersparky]

if its your main switch "tripping" i think your sleep walking

 

[RMS]

Your main switch is a switch dissconector, this will not trip under fault conditions, its more likley to be some sort of rcd that will trip??????

 

[Thermo]

its only happening at night, on very irregular occasions, not every night, probably about 5 times in the last 3 months. It is definetly only the main 100 amp switch that is going. No other breakers are tripping as you would expect with a fault. it was fitted by a qualified sparky a few years ago, who i know and trust. Either that or ive got a ghost!

 

[Steve]

its only happening at night, on very irregular occasions, not every night, probably about 5 times in the last 3 months. It is definetly only the main 100 amp switch that is going. No other breakers are tripping as you would expect with a fault. it was fitted by a qualified sparky a few years ago, who i know and trust. Either that or ive got a ghost!

main switches aren't MCBs, they are just a switch. So i would think that its a faulty / weak spring in the switch.