scope:

This standard applies to all equipment and power supply wiring, from the point where it enters the room or apparatus case up to the point of supply for individual circuits, which is usually in the form of a feed fuse or circuit breaker.

The following list is a guide to the scope of this engineering standard:

a) all wiring, transformers, switching equipment and protecting equipment from the 600V AC signal main links or isolators to the feed bus bars, and to other power supply units;

b) low voltage supply units, and feeds from these to bus bars, including rectifiers for DC supplies;

c) uninterruptible power supplies;

d) 230V wiring from the room consumer unit to any signalling apparatus;

e) power supply units for any computer apparatus;

f) batteries.

This standard supersedes E7157-A3 and TLL-ENG-S7255-A1 , which are withdrawn.

Note 1: Workshop overhaul of signalling power supply equipment is not covered by this standard.

Note 2: The maintenance of Jointless Track Circuit power supplies is not within the scope of this standard. This is covered by engineering standard S2526.

Note 3: The maintenance of cable runs is covered by engineering standard S2544.

Purpose 

This standard defines the minimum maintenance requirements for signalling power supplies.