I HAVE A DUAL RCD CONSUMER UNIT WITH 1 X 80A (30MA) AND 1 X 63A (30MA) RCD'S
I CAN PUT 2 X 40A SHOWER MCB'S PLUS A 32A MAINS CCT MCB ON THE 80A RCD BUT IF I TRANSFER ANY OF THEM TO THE 63A RCD THEY TRIP BOTH THE RCDS .
THE ONLY MCB'S I CAN USE ON THE 63A RCB ARE THE 6A LIGHT CTTS
WHAT AM I DOING WRONG.