RCD Tripping

[mattyhop]

One of my electricains on site has just called me with a very strange problem. We have installed a 18 way split load board into a domestic dwelling as normal, he tells me that if he turns all of the breakers on that are on the RCD side the RCD trips, but if he leaves 1 of them off it does not trip? my first thought was that the circuit he turns on last has a fault but he assures me if he turns this on on first and leaves another off its ok. I am 100% sure its not over loaded, please advise.
Many Thanks

 

[Spudnik]

Dual RCD CU?

Sounds to me like he has the neutrals for each RCD swapped over and connected to the wrong bars.

 

[mattyhop]

Split load, with a small lighting board coming off of the rcd side as well

 

[Spudnik]

This kind of fault where RCD's are tripping randomly are generally down to installer error as i explained above.

It could be a circuit neutral in the wrong place also.

Maybe get your electrician to check and double, double check.


I do this more often than i care to admit.

 

[pete.l]

Has he tested all of the circuits? Could be a neutral to earth fault, or a faulty appliance. Had many leaky fridges/freezers, also vaccuums(is that how you spell it!).

 

[mattyhop]

Cheers guys, I have visited site and changed the RCD! seems to have been a fault on that. One of those one where you try everything and the last thing to check it is.