RCD instantly tripping??

[CRAIGNEWHAM]

Evening,
Just installed a new CU for a customer and one of the RCD's trips as soon as its switched on, even though the circuit beakers arent even on. Any suggestions about how to look for the fault?
Its 3 socket radial circuits that are causing the problem as it will stay on when I disconnect them?
Any help apprecaited
Craig

 

[telectrix]

Its 3 radial socket circuits that I had to disconnect. Could it be that these are interconnected??

get a tester on the radials. make sure there's no continuity between the 3 circuits, then IR test between them. could be a common neutral bridged across. are the 3 radials all on the same RCD?

 

[Andy B]

If they are all on the same rcd although its not correct it probably wont cause the rcd to trip. Can you not test it and see if they are interconnected.

 

[CRAIGNEWHAM]

I'll do that tomorrow

 

[CRAIGNEWHAM]

Yeah, there all on the same RCD

 

[telectrix]

have you tried connecting each radial in turn?

 

[CRAIGNEWHAM]

Ive tried connecting them seperately, and they trip still

 

[Hagar]

Got the same prob with a memera 2000 split box already has a ring main in working fine a cooker circuit working fine, i have just put two dedicated circuits in, one for a griddle one for a counter top boiler nothing else connected to either circuit, as soon as i turn the griddle on out goes the trip brand new cable 20amp switch etc checked cable with megger no faults if i move the mcb to the non protected side griddle works fine, boiler takes the rcd trip out even though its not fed through it any idea's ??


Hagar