Standards Development

Scope

This British Standard provides recommendations for earthing of electrical installations, including:

a)    protective earthing of low voltage installations to BS 7671;

b)    the interface between LV and HV substations conforming to BS EN IEC 61936-1:2021 within buildings;

c)     protective earthing arrangements for generators running in parallel with a distribution network operators (DNO) or a private HV/LV transformer supplying low voltage installations;

d)    protective earthing and changeover switch arrangements for UPS and generators supplying low voltage installations; and

e)    AC supplies derived from DC supplies, e.g. solar, batteries, wind.

NOTE 1 The earthing arrangement of a system or installation is typically provided for safety reasons and is not to be confused with the bonding arrangement required by other British Standards (e.g. BS 7671).

This British Standard applies to land-based installations in and around buildings.

NOTE 2 Whilst many of the principles of this British Standard can be applied equally to low voltage DC systems, this British Standard does not cover issues such as protection against galvanic corrosion that might be necessary for DC systems.

This British Standard does not include recommendations for maintenance of earthing systems and referenced conductors.

NOTE 3 Attention is drawn to the Regulation 4 of the Electricity at Work Regulations 1989 [2] and Regulation 3 of the Electricity, Safety Quality and Continuity Regulations (NI) 2012 [3] with regard to maintenance.

This British Standard does not apply to:

1)      ships, aircraft, offshore or mining installations;

2)      earthing of medical equipment [see BS EN 60601 (all parts)];

3)      special problems encountered with solid state electronic components;

4)      equipment sensitive to static electricity;

5)      requirements for functional earthing;

6)      railway traction equipment, rolling stock and signalling equipment;

7)      earthing of overhead lines between electrical installations; and

8)      the internal protection of electrical equipment and apparatus.