BS 7430 is a British Standard which provides recommendations and guidance on meeting the requirements for the earthing of electrical installations.

BS 7430: 2011 replaces BS 7430: 1998 which has beeen withdrawn

It covers:
- Protective earthing of low voltage (LV) installations to BS 7671:2008+A1
- The interface between LV and HV substations of 11 000/400 V to BS EN IEC 61936-1:2011 within buildings
- Protective earthing and changeover switch arrangements for generators supplying low voltage installations.

BS 7430 applies only to land-based installations in and around buildings.

It does not apply to:

1) Ships, aircraft or offshore 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) Earthing of overhead lines between electrical installations; or
7) The internal earthing of equipment

BSI online

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