I would like to have an electrical supply to my greenhouse next to the garage. The garage has an existing 8-way cu (about four years old) with a 30 mA rcd and two mcbs for the garage power and light. The garage cu is connected to an mcb in the house cu protected by a 100 mA rcd.

I am considering a small ip65 cu in the greenhouse with a 30 mA rcd and two mcbs. My problem is in the connection from the garage cu to the greenhouse cu. I want the greenhouse to be independent of the garage cu’s rcd, as I don’t want the greenhouse to trip the garage supply. I was considering a conversion of the garage cu to a split load cu, feeding the greenhouse from the unprotected side, but I think that there is only one neutral bar in the cu.

Can the garage cu be converted, or is there an better way to do this?

Thanks for that Scot. When I searched for a solution I came across a posting where the lack of a second neutral bar was overcome by connecting the non-protected neutral to the load side of the main switch. This is neat and less costly than rcbo's, but is it acceptable?

(Later) I've just taken the front off the cu (a Steeple) and it is most peculiar, with a rail that isn't the usual din shaped, more a flat strip with a crease at the top on which the Steeple mcb's hang. They seem to be fixed from the rear. I don't know whether other mcb's would be compatible. I'm beginning to go off the idea.