Electrical installations in caravans and motor caravans (§721)

The 708-camping guide covers the shore-power supply at the campsite — the distribution board and socket-outlets a caravan or motor caravan is connected to. §721 (based on IEC 60364-7-721) regulates an entirely different part of the chain: the fixed electrical installation inside the caravan or motor caravan itself, intended for habitation use.

Scope — what §721 does and does not cover

§721 applies to the electrical circuits and equipment intended for the habitation use of the caravan or motor caravan. The standard explicitly does not apply to:

the vehicle's own automotive circuits (the 12V on-board network for lighting, engine, brakes, etc.);
mobile homes, residential park homes, and transportable units — these fall under other parts of the installation standards, not under §721.

This boundary prevents the caravan's separate 12V vehicle network (battery, lighting, braking system) from being confused with the 230V habitation installation fed via the shore-power connection.

The shore-power inlet coupler

The caravan or motor caravan is connected to the campsite distribution board (see the 708 guide) via a fixed inlet coupler on the outside of the vehicle, compatible with the industrial (CEE, blue) 16A plug used at the campsite. From that inlet coupler, internal wiring feeds the habitation distribution board inside the caravan itself.

RCD and protective conductor in the caravan's own installation

The fixed 230V installation inside the caravan needs its own residual-current protection — the presence of an RCD in the campsite's distribution board (§708) does not automatically protect against a fault that develops within the caravan's own wiring, downstream of the inlet coupler. In practice, the caravan installation is therefore executed much like an ordinary domestic installation: its own RCD (typically 30 mA) in the internal distribution board, plus bonding of all accessible metal parts of the fixed installation to the protective conductor.

Note: this article gives the principle and the scope boundary. The exact requirements for circuit layout, cable cross-section and the precise RCD configuration in the caravan installation follow from the full standard and the vehicle manufacturer's documentation.

Practical relevance

When (re)building or inspecting the fixed 230V installation in a caravan or motor caravan (for example after a DIY conversion adding socket-outlets or an air-conditioning unit), it is important to establish that the 12V vehicle circuits and the 230V habitation circuits remain physically separated, and that the habitation installation's own RCD and protective conductor are intact — a separate check from inspecting the campsite's shore-power supply itself.

Common mistakes

Assuming the campsite's RCD (§708) takes over full protection of the caravan installation — a fault arising after the inlet coupler, within the caravan's own wiring, needs that installation's own RCD.
Mixing 230V habitation wiring with the 12V on-board network during a DIY conversion — §721 explicitly does not cover the 12V automotive circuit, and mixing the two networks is a safety risk.
Treating a residential park home or transportable unit as if it fell under §721 — those fall under other parts of the standard; §721 is specific to caravans and motor caravans as defined in the standard.