One of the first things that I had installed in this camper was the external mains connection, which would allow to connect an external 240V AC power into the vehicle. I had use this already for powering a heater fan, when working during the autumn months in the rear of the vehicle.
But for regular use of 240V, for example at campsites, it is important to install proper circuit breakers when connecting to the camp site's power. From eBay I had ordered a while ago a small circuit breaker box, for a maximum current of 16A, which seems sufficient to me. The box is watertight. The power distribution is in a watertight junction box, to which the power plugs are connected. The power plug box itself is currently not of a watertight type, but maybe I will change this later.
I decided to affix these boxes (fuse box, distributor box, power plugs) at the back of the vertical panel, so that they would not take away more valuable space inside the vehicle. There is enough space, as the rear window in the small right barn door leaves a large gap. Below these boxes is a battery charger which can charge the battery once external power is connected.