Consumer unit

The consumer unit is the UK term for the 230 V distribution board inside a motorhome or caravan. It includes a main isolator, an RCD (30 mA residual-current device to protect against electric shock), and several MCBs (6/10/16 A circuit breakers) feeding the sockets, converter, boiler, and air conditioner. On the continent it is more often called a distribution box.

Typical UK layout: 1× 30 mA RCD + 3–4× MCBs (16 A sockets, 10 A boiler, 6 A converter, 6 A 230 V lighting). Press the RCD TEST button once a year — it must trip in under 30 ms. BS 7671 and EN 1648 require the unit to be accessible without tools (a screw or clip-on lid). At a habitation check the engineer measures earth resistance (<1 Ω) and trips the RCD with an injector tester.