scope:

This engineering standard applies to all main earthing and bonding of all electrical systems on the LU network irrespective of where power supplies are derived from and includes protection against lightning.

This engineering standard shall be used to determine the correct earthing and bonding arrangements for interfaces between different electrical systems and shall be applied when:

a) new electrical systems or subsystems are proposed;

b) alterations are proposed to existing electrical systems;

c) any change is proposed to existing interfaces (internal or external to LU) or where a new interface is proposed;

d) earthing of temporary structures (scaffolding, etc.);

e) temporary electricity supplies including generator fed supplies.

This standard applies to all activities undertaken for new or modified electrical systems however this standard is not retrospective. Excluded from the scope of this standard is:

a) Earthing and bonding of rolling stock; except that for the purposes of this standard, it is assumed that all rolling stock will be capable of projecting rail potentials to accessible parts, and as such this must be considered as part of any Step and Touch voltage assessment under this standard.

This is a new standard that supersedes PEE-SPE-12-041-A2 and PEE-STD-01-002- A3, and is applicable to all LU Suppliers.

Purpose 

To define the earthing and bonding requirements across the London Underground (LU) network such that it is compliant with statutory legislation, British and European standards to ensure electrical safety for personnel and public. 

This engineering standard aims to ensure that new and altered earthing and bonding arrangements are compatible with neighbouring electrical systems and external railway networks and are correctly designed, managed and maintained.