scope:

This standard applies to LU and LU Suppliers installing new or modifying existing fixed equipment, cables and systems on the LU power system.

This standard does not apply to 230 volts a.c. single phase systems, railway signalling systems, telecontrol RTU's, circuits below 50 volts, telecommunication equipment and electronic and similar sensitive components.

This standard excludes induced overvoltage, impulse and specialised voltage testing.

Purpose

This standard states the mandatory requirements for on-site voltage withstand testing and associated insulation resistance testing of major items of fixed electrical power supply equipment, cables and systems on London Underground (LU) power system.

This standard also provides the requirements on the selection of test voltage values and duration when putting new equipment and cables into service for the first time, and when returning existing equipment and cables to service following work which has affected the performance of insulation.