I’ve been asked to install an electric shower for a customer 9.5kw. I no the cable size and everything it ok, but I need to put it on a separate board as there’s no room left in the current one. The current one is a split board with 2 rcds on it. Is it acceptable to add another rcd into my new board coming off one of the old ones and have the shower supplied into that? And is a 80a 30ma rcd fine for this?