I am installing a new electric shower. I have taken advice on the cable and am now having to install a new dedicated consumer unit as the old hard fuse box has no room. I understand both a MCB & RCD are needed and have purchased these. Most diagrams show the RCD connected after the MCB. However the RCD came in a case with connections for two tails on the top and outlet to a bus bar and neutral on the base. The MCB comes as a small unit to clip on a bus bar. If the MCB is put onto the bus bar in the RCD box with the shower cable connected to it it ends up being after the RCD in the circuit instead of before it. Is this just as acceptable or do I need another box just for the MCB to make sure it is before the RCD?