NSI 26

NSI 26 details the safe working arrangements on railway feeders where the alternative return currents need to be eliminated from the work area.

This arrangement is very similar to my last 275kV cable repair where the cable was connected to an overhead line at both ends and I needed to eliminate possible fault currents and transfer potential in the joint bay.

The NS 5 jointers earths are approx. 15mmsq and although very good for induced voltages have a poor fault rating. Back in those days NSI 26 was an NSI number waiting to be allocated and I found it difficalt deviating from the conventional guidance of NSI 5 which back then and now does not lend itself to working with single point earthing.

The pass mark is set at 90%

National Grid NSI 26 Training
Lesson Plan



Course Title:Railway Connection Circuits
Pre Course Qualifications:

The course covers working on National Grids Railway Connection Circuit(s).

Candidates should ideally be Competent Persons and hold BESC for Substations (safety rules and NSI 6 & 8) and the relevant practical knowledge, training and experience to work on earth systems.

Objectives:

To enable safe and effective work processes in compliance with National Grids safety instruction NSI 26.

To understand the role and responsibilities of a Competent Person and SAP within National Grids environment.

Note: Words in bold are terms defined in National Grids fourth Edition Safety Rules. Words in italics are definitions found in NSI 26.

At the end of the training:

On completion of the training the candidates will have received sufficient information instruction and guidance to enable competence.

The candidate will partake in an assessment to confirm his/her knowledge and understanding.

Duration:

1/2 Day (Number of candidates approximately 10)

Course Content:
  • History of rail electrification
  • Typical arrangement - advantages and disadvantages
  • BT mode
  • AT mode
  • BT mode current flow diagram
  • AT mode current flow diagram
  • Inside of the Train
  • UK electrified lines
  • Purpose and Scope
  • Definitions
  • Dangers
  • Control of Alternative Current Return (ACR) current
  • Switching and establishing ACR safety precautions
  • Management of Links
  • Inadvertent ACR current parallel paths
  • Working on Cables
  • Testing
  • Example of a completed Safety Document
  • Switching Instructions for Railway Connection Circuits
  • Configurations Index
Requirements:
  • Training room
  • Digital Projector (optional)
  • Screen (or suitable light coloured surface)
  • Flip chart or white board and pens
  • Pens and paper for candidates
  • Name Cards
  • Tea/coffee machine or facilities to make drinks
  • Lunch arrangements (lite snacks or sandwiches)
Trainer:

Barry Hodgetts