scope:

This standard specifies the instructions for the making out, issuing and cancelling of Permits to Work, Sanctions for Test and Circuit State Certificates (including HV Isolation & Earthing Certificates) for work on Network Rail owned or operated high voltage equipment. This also includes the instructions for the interface with TNOs and DNOs at supply points and also when working at the interface with 25 kV AC and 1500 V DC OLE systems.

This standard also specifies the actions required to make high voltage equipment safe prior to and during the issue of safety documentation. They apply to work on high voltage equipment in switching stations and substations, and on high voltage equipment forming part of Network Rail controlled infrastructure including electric traction systems and high voltage non-traction systems (i.e. high voltage switchgear supplying passenger stations, rolling stock depots, maintenance depots, etc).

This standard does not apply to equipment covered by the following Network Rail standards (however the requirements when interfacing with such equipment might be stated within):

a) AC electrified track: any electrical equipment or overhead line equipment covered by NR/L3/ELP/29987 or NR/L3/ELP/SAI25, (e.g. Auto Transformer Feeder cabling).

b) DC electrified track: any electrical equipment covered by NR/L3/ELP/3091, NR/L3/ELP/27051 and NR/L3/ELP/27052.

c) DC electrical equipment in 650 V / 750 V DC traction substations covered by NR/L3/ELP/21060; (e.g. rectifier transformer).

NOTE 1: Where an interface on AC electrified track is not explicitly captured in NR/L3/ELP/29987, then the risk assessment approach detailed within NR/L3/ELP/29987 should be used.

NOTE 2: Where an interface is not covered in the standards stated in b) and c), then a risk assessment is required to demonstrate how the electrical safe system of work will be managed at the interface. This risk assessment is required to be authorised by the E&PME or the DPE or the Route HoA [E&P] (or equivalent), for both maintenance and project work prior to any work being undertaken.

This standard also does not apply to the following equipment:

d) signalling power distribution networks (where the system voltage is below 1000 V AC);

e) HV electrical equipment that is completely disconnected from all possible sources of HV supply and is not part of the operational infrastructure; 

f) work on electrical equipment fitted to traction or rolling stock;

g) ETH Shore supplies (where the system is entirely below 1000 V AC); and

h) 750 V DC traction distribution equipment that supplies overhead line tramway equipment unless specified by the RHoA [E&P]. 

Purpose 

This standard specifies the requirements for making high voltage traction and high voltage non-traction distribution equipment safe to work on within Network Rail managed infrastructure