Consumer Unit

[JBELESER]

Consumer unit change was done on Domestic dwelling.
New consumer unit was a split load x2 RCDs.

After installation, inspection and Tests, one of the RCDs trips whenever I load the other RCD. I mean if I put a load say plug in an appliance on a socket the other RCD, or switch the oven on, the other RCD trips even though the appliance plugged in this RCD is still working.

I have checked to be sure there are no crossed neutrals. But it still keeps tripping

What comment do you have please???

Regards.

 

[GLENNSPARK]

whats the earthing arrangements?

caus a neutral-earth fault can cause this....in fact its got to be a neutral-earth fault as it only manefests itself when a load is applied

 

[GLENNSPARK]

further more it depends on how much leakage the RCD thats tripping is being subjected to..in regards to the one thats holding...and the tripping threshold of that individual device of course...

 

[GLENNSPARK]

are the tails from each RCD in the correct neutral bar?

 

[JBELESER]

The earth arrangement is PME or TNCS

Yes the tails are in the right place

 

[GLENNSPARK]

The earth arrangement is PME or TNCS

Yes the tails are in the right place

rite:

its a neutral earth fault...coming back through the PME block....

drop the neutrals out and test to earth...find the offending circuit...then divide & rule on the circuit (split it roughly in half)...this way you can negate half straight away....saves time see....

 

[jaypp]

is the oven spurred off ring? ring continuity or would both rcds go?

 

[GLENNSPARK]

is the oven spurred off ring? ring continuity or would both rcds go?

hmm...good point....

to the OP:

is the oven on a plugtop off the ring final?

 

[JBELESER]

I will test all neutrals to earth and see. Thank you.

The oven has its own circuit.

 

[JBELESER]

No. The oven has its own circuit on a 6mm

 

[GLENNSPARK]

rite...

off you go with the megger...

make sure all connected loads are dropped out first....

check the finals...if its clear then go for the loads....

 

[JBELESER]

Ok. When I did the testing, every circuit was tested for Insulation Resistance and they were all ok before switch on.
It is a very strange fault.

 

[GLENNSPARK]

Ok. When I did the testing, every circuit was tested for Insulation Resistance and they were all ok before switch on.
It is a very strange fault.

rite so any work done here after the install was energised?

 

[ipf]

Found it yet?

Oh sorry, it's 12.20.

 

[Plonker 3]

Do a global N-E IR test , with all loads disconnected obviously.