Contactum Consumer Unit RCCB Problem

[RodA]

My Contactum consumer unit has two RCCB's fitted, one has seven MCB's off it and the other five MCB's off it.

The RCCB with the five MCB's keeps intermittently tripping out, it can go for weeks without tripping, then perhaps goes twice in a week. As the fridge and freezer are on this RCCB one day I will come home to defrosted food!

When the RCCB trips none of the MCB’s off it trip as well, so I don’t know which of the five circuits has the problem.

Any suggestions as to how I can trace the problem, is a fridge or freezer with an intermittent earth leak fault a likely candidate for the problem more than say a TV that doesn’t use an earth?

Thanks for any suggestions.

Rod

 

[333rocky333]

not that easy im afraid, if you have money to burn, consider having an all rcbo board

 

[PrenticeBoyofDerry]

It's normally a process of elimination, which would involve disconnecting a circuit at a time, to find which circuit is causing the problem.
But as the RCD is not tripping immediately once set, it's not that simple.
If the fridge/freezer is a concern, swap the circuit cables (Line and neutral) with one rated the same on the second RCD side.
If this then causes the second RCD to trip, you have found your problem circuit, if the original RCD trips, you have eliminated at least the fridge/freezer circuit.
Other than that you require some further investigation via inspection and testing.
Have you had any work done in the property prior to this fault occurring and any water issues?
Could be worth checking out for any loose terminals and tightening them back up.

 

[RodA]

No water problems or recent work carried out, the very intermittent nature of the drop out is very puzzling, and not related to anything being turned on etc.

The idea of swapping the fridge and/or freezer over to the other RCCB is a good idea, they are on separate MCB’s but the same RCCB at present

I had the idea of removing the fridge and freezer circuits from the consumer unit and fitting a separate consumer unit with two RCBO’s, one for the fridge circuit and one for the freezer circuit. I’m thinking if it is one of these appliances at least that would will prove it, if not they will not go off when the fault occurs.

Can you see any problem with that?

 

[securespark]

But are they on separate circuits?

 

[RodA]

The fridge and freezer have their own MCB, but into the same RCCB.