scope:

This standard applies to all TfL and LU staff and any contractors, sub-contractors or suppliers working on behalf of TfL or LU.

This standard applies to all LV electrical distribution, sub-distribution, final circuits and installations on LU premises as follows:

a) For installations supplied from the LU Low Voltage Alternating Current (LVAC) supplies, from the Delivery Point as defined by LU standard S1105

b) For Tunnel Lighting controls supplied from the LU Direct Current (DC) traction conductor rail

c) For installations supplied by a Distribution Network Operator (DNO) to LU dedicated local High Voltage (HV)/LV transformers, from the LU owned point of isolation on the secondary side of the transformer

d) For installations supplied from a DNO LVAC supply, from and including the outgoing cable at the DNO cut-out

e) For installations supplied from self-generating power supplies, including the power source.

Note: This standard does not apply to Off Line Battery Inverters (OLBIs), DC traction systems and signalling supplies at 33.3Hz and 125Hz.

This standard does not apply to low voltage electrical installations in substations and similar power buildings. These are the responsibility of Power Engineering and the requirements for these buildings are provided in S1914. The Power Engineer may choose to adopt some elements of S1069 where deemed appropriate.

Purpose

The purpose of this standard is to ensure that Low Voltage (LV) electrical sub-distribution systems and installations on London Underground (LU) premises are designed, installed, maintained and operated in a safe and effective manner.