Outdoor socket-outlets — minimum IP44, mandatory 30mA RCD and the distinction from fixed outdoor lighting (§714)

The [guide on §714 — outdoor lighting installations](/guides/nen-1010/714-buitenverlichting) covers fixed outdoor luminaires. A different part of an outdoor installation, at least as common in practice, is the outdoor socket-outlet: intended for connecting portable equipment such as garden tools, a pressure washer, or patio lighting on a flex. Different, specific requirements apply to that socket-outlet than to a fixed-wired outdoor luminaire.

Minimum ingress protection rating: IP44

An outdoor socket-outlet, unlike an ordinary indoor socket-outlet, must withstand splashing water and the ingress of foreign solid objects from outside. The minimum ingress protection rating for this is IP44 (protection against solid objects ≥1 mm and against splashing water from any direction) — see also the guide on external influence classification codes for the underlying AD water classification on which this IP requirement is based. For more intensive or commercial use — for example an outdoor socket-outlet on a construction-site-like location, or where hosing down with water occurs — IP55 (additional protection against dust and against water jets) is recommended above the legal minimum.

An ordinary indoor socket-outlet with a hinged cover is not sufficient for this: such a cover generally only protects against incidental splashing with the plug removed, but does not provide IP44 protection with the plug inserted — and it is precisely that situation (equipment operating outdoors while it is raining) for which an outdoor socket-outlet must actually be protected.

Mandatory 30mA RCD, regardless of the environmental class

Independent of the exact IP classification, a mandatory 30 mA residual current device (RCD) applies to every outdoor socket-outlet for general use, in line with the general principle of §411.3.3 for socket-outlets up to 32 A intended for general use by ordinary persons. This weighs particularly heavily outdoors: damp ground, wet hands, and the use of electric garden tools in direct contact with the earth significantly increase the risk of a dangerous body current in the event of an insulation fault, compared to a dry indoor environment.

Why a separate circuit is preferred

Although not strictly mandatory in every situation, it is strongly preferred to connect outdoor socket-outlets on their own, separate circuit with its own 30 mA RCD, rather than sharing an RCD with indoor circuits:

A fault or leakage current during outdoor use (for example a damaged extension cord in the garden) then does not also trip the power supply of indoor circuits.
When tracing an unwanted RCD trip, the fault location can be directly traced to the outdoor circuit, instead of first having to rule out all indoor circuits connected to the same RCD.

Cabling to the outdoor socket-outlet

The supply cable to an underground or outdoor-mounted socket-outlet must be suitable for the relevant environment (moisture-resistant, with sufficient mechanical protection for underground installation — see the guide on underground cables and excavation depth for locating existing underground routes before excavation work) and must be connected to the main earthing terminal of the installation with a protective conductor of sufficient cross-section.

Note: this article covers the ordinary outdoor socket-outlet for general use. For socket-outlets in specific outdoor locations with their own standard chapter — a marina (§709), a campsite (§708), or a construction site (§704) — additional, stricter requirements apply on top of what is covered here; see the relevant guides for those locations.

Practical relevance

When assessing an existing outdoor socket-outlet, it is important to check whether the actual IP classification with the plug inserted is at least IP44 (not only with the cover closed and no plug), whether it is connected via a 30 mA RCD, and preferably whether it is a separate circuit relative to the indoor installation.

Common mistakes

Mounting an ordinary indoor socket-outlet with a splash-proof cover outdoors — this provides no IP44 protection once the plug is inserted, precisely the situation in which protection is needed.
Assuming the 30mA RCD requirement only applies with a wet-location classification — the requirement applies to every outdoor socket-outlet for general use, regardless of the exact AD water class of the location.
Letting outdoor socket-outlets share the same RCD as indoor circuits — a fault outdoors then unnecessarily also trips indoor circuits, and complicates locating the fault.
Assessing the IP classification of the socket-outlet itself without including the mounting box or flush-mount installation — an IP44 socket-outlet in a non-watertight flush-mount box does not achieve the required protection for the assembly as a whole.