Please help. I have a basic understanding of electirics, but 5 Electricians are stumped and I don't know where to go next. My mother in law heats her house by 4 Night Storage Heaters, all of which are wired to a Economy 7 supply/fuse board, with no RCD just MCB. The largest of the Night Storage Heaters began to fail and trip the MCD. To cut a long story short, she ended up having a new one fitted. Unfortunately this new one also now trips the MCB. The electricians have tried swapping the various supplies to the various heaters around in the E7 fuse board and the same heater is tripping the different MCB. It would be an obvious thing to consider that there is a fault on the circuit between the board and the night storage heater. However, they have now wired it into the day time board and it is not tripping. Has anyone got any ideas as we need to get it wired back into the E7 circuit??