scope:

Purpose

This Earthing and Bonding specification is unique to the North Pole Depot area and the section of the West London Lines between West Way and Mitre Bridge Junction, it should be read in conjunction with NR/SP/ELP/21085 which contains general information regarding standard bonding practices, cable sizes, use of spider plates etc.

There are 3 different types of electrification within the North Pole International Depot complex :

25kV 50Hz a.c. Overhead Line Conductor System

660V d.c. 3rd Rail Conductor System

3,000V d.c. Overhead Line Conductor System

Bonding areas

There are, in vary degrees, both a.c. and d.c. traction return current circulating around the depot complex, and to identify the special earthing and bonding requirements for various parts of the complex, the depot has been sub-divided into the following areas :-

The area where the connections between the traction earth return system and the running rails have been specifically located to minimise the possible effects of the d.c. circulating current in the earth conductors.

The area with no special provision for d.c. circulating currents and where the traction earthing requirements will be arranged in accordance with NR/SP/ELP/21085.

Drawing No.1 depicting these areas is appended (Appendix "A") to this specification.