ac1951 wrote:
Hi all,

I just fitted a Contactum 20A RCBO into a Contactum 17th edition CU.
I installed it on one of the non RCD protected ways.

I have connected the blue wire from the RCBO to the incoming Nuetral
bar and this is also the point where the CCT (being supplied by the
new RCBO) Neutral is connected.

However, as soon as anything is connected to the cct the RCBO trips.
I have moved the cct onto a spare 16A MCB protected by one of the CU's
30mA RCDs and have no problems !!

Am I missing something or is the RCBO duff ........

thanks
Andy

The neutral of the circuit should be connected to the neutral output of
the RCBO, NOT the consumer neutral rail directly.

If it is one of these
http://www.tlc-direct.co.uk/Images/P..._3/CPBR201.JPG

Then if you look at the top of the unit, it appears there is a N Out
terminal on the top somewhere!

Toby...