Outdoor Power
where there is the presence of water or high humidity. Regulation 522.3.1 requires that a wiring system is selected and erected so that no damage is caused by condensation or ingress of water. The selection of accessories having an appropriate IP rating whilst ensuring the IP rating is not compromised during installation is a critical aspect of ensuring that wiring systems are not adversely aff ected. The IP rating of equipment must be suitable for the location (522.3.1). To help designers/installers to make suitable choices, Scolmore produce a range of weatherproof accessories (Aquip66) which have an IP 66 rating. This rating provides ‘dust tight’ protection against ingress by objects and ‘power water jets’ protection against ingress by water. Impact – Regulation Group 522.6 requires wiring systems to be selected and erected to minimise damage from mechanical stress. This will include for example, abrasion, penetration, tension, or compression (522.6.1). It might be necessary also to consider the suitability of the IK rating of the equipment is suitable, such as IK08 for equipment used in marinas and similar locations (709.512.2.1.4). The standard BS EN 62262 relates to IK ratings, to identify the degree of protection provided by enclosures for electrical equipment against external mechanical impacts. Whilst these general requirements exist in Section 522, specific locations will have particular needs. For example, Part 7 details a range of installations where it will be necessary to take additional precautions when designing the electrical installation. Such locations will include for example, agricultural and horticultural locations, construction and demolition sites, caravan and camping parks, marinas, and similar locations. These locations have additional requirements over and above those detailed in Section 522.
When designing/installing systems and equipment, care should be exercised to ensure that not only the wiring system but that the
“The designer/installer must factor into their design all relevant external infl uences as well as simply selecting the correct size and type of cable.”
associated accessories and electrical equipment is suitable for use and takes account of all the relevant environmental factors.
Shock risks
As most equipment installed outdoors is accessible to touch, there is an increased risk of electric shock for persons who are also in contact with the general mass of Earth.
By way of a tragic example, on 11 September 2018, a young boy died whilst playing with a friend in a pub garden. The boy had sat on a light and touched a metal railing resulting in
an electric shock that proved fatal. The local distribution board was found to be unearthed and there had been multiple warnings about the safety of the electrical installation. The introduction of RCDs having a rated residual operating current not exceeding 30 mA into the UK wiring regulations, was to provide additional protection against electric shock. When there is a fault to earth, RCDs provide a faster way of disconnecting electric current than typical overcurrent protective devices such as fuses and circuit-breakers.
Whilst Regulation 411.3.3 requires 30 mA RCDs to be installed when supplying socket- outlets and Regulation 411.3.4 requires 30 mA RCDs to be installed for circuits with luminaires in domestic premises, it is Section 714 which requires 30 mA RCDs to be installed to provide additional protection for circuits supplying lighting which is accessible to the public (ordinary persons) (714.411.3.4).
Regulation 714.411.3.4 provides examples of accessible lighting which requires additional protection by a 30 mA RCD. These include gardens (including beer gardens), spaces open to the public, telephone kiosks, bus shelters and advertising panels and town plans. Whilst 714.411.3.4 details some exclusions, the example list is not exhaustive, and the designer/ installer should be careful not to exclude a suitably rated RCD.
Conclusion
The designer/installer should ensure that all necessary external infl uences have been factored into the selection and erection of the wiring system and associated accessories. Furthermore, all circuits supplying socket-outlets for use outdoors and all accessible lighting must be protected by a 30mA RCD.
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