RCD Was Tripping Out

[wreck-it-steve]

We have a dual RCD consumer unit and the other day the left RCD was tripping at random times. We though we had an electrical fault so started to investigate....

The next day the power went off altogether and we had to call the supplier who cam out to look. It turns out we had a beak in our mains cable under the road.

The guys that cam to do the repair said this would have been the cause of the RCD tripping.

My question is why and why only one RCD and not both?

Thanks

 

[RF Lighting]

It might be that one is faulty, maybe one is slightly more sensitive, or more likely it'll be to do with how much load is connected to each RCD. A heavier loaded RCD will be more sensitive to this sort of fault.

Have you pressed your test buttons recently to check both RCDs operate?

 

[Adam_151]

A series arcing fault can introduce higher frequencies than 50hz into the wiring, at these frequencies, leakage to earth through cable capatance is increased.

Which combined with what RF says, may not be enough to trip an RCD on its own but when combined with other leakage, might just be enough

 

[wreck-it-steve]

Thanks for your replies guys. The RCD is working when the test button is pressed.