Mobile or transportable units (§717) — installations in vehicles for commercial use

The 721-caravans guide covers the fixed 230V habitation installation in a recreational vehicle. §717 (based on IEC 60364-7-717) regulates a different kind of vehicle installation: the electrical installation inside a commercial mobile or transportable unit — a vehicle and/or transportable structure containing all or part of an electrical installation, intended for a specific commercial purpose.

Scope — what does fall under §717

Typical examples the standard itself names: units for television and broadcasting purposes, medical services, advertising, fire fighting, special IT applications, disaster relief, and catering units. Recognisable in Dutch practice: a food truck, a mobile blood-donation bus, a broadcaster's outside-broadcast van, a mobile X-ray or dental unit, or a transportable emergency-relief post.

What explicitly does not fall under §717

To avoid overlap with other standard sections, §717 explicitly does not apply to:

Generating sets — those fall under a different part of the standard.
Pleasure craft — see instead the 709-marinas guide for the shore-power side; the vessel installation itself falls under its own maritime regulations.
Caravans and motor caravans — those fall under §721, specifically for recreational/habitation use, not for commercial units.
The vehicle's own automotive circuits (the vehicle's own on-board network for driving, lighting, braking).

This delineation prevents a commercial mobile unit from being wrongly assessed against the recreational caravan requirements of §721, or vice versa.

Multiple units coupled into one installation

A particular feature of §717: if two or more units are connected together to form a single electrical installation (for example a main unit with a coupled trailer unit at a large event, or an extended healthcare unit), the requirements of §717 apply to that coupled installation as a whole — including equipotential bonding between the units, not just to each unit individually.

Note: this article gives the scope and the principle. The exact requirements for each unit's own means of isolation, the supply connection point, and the equipotential bonding between coupled units follow from the full standard.

Practical relevance

When building, inspecting or hiring out a commercial mobile unit (food truck, mobile healthcare or test unit, broadcast van), it must be established: does this unit actually fall under §717 (commercial use) or under §721 (recreational use as a caravan/motor caravan), is there a dedicated means of isolation per unit, and — where applicable — is the equipotential bonding between coupled units correctly implemented.

Common mistakes

Assessing a commercial mobile unit against the §721 caravan rules (or vice versa) — both standard sections have their own, non-overlapping scope.
Treating the unit's own generating set as part of the §717 installation — generating sets fall outside this standard section.
Assessing coupled units individually without accounting for the equipotential bonding of the combined installation.