Insulated working under impressed voltage conditions (NSI5 equivalent for contractors)

£1,250 +VAT

Course Duration:

One Day

Format:

In-Person

Location:

Stoneleigh Park

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Course Overview

The Insulated Working Under Impressed Voltage Conditions (NSI5 Equivalent) course provides essential training for contractors and operatives who work on or near high-voltage equipment. This accredited programme equips delegates with the skills and knowledge to safely carry out live working on insulated electrical systems under impressed voltage conditions, ensuring compliance with industry safety standards.

Designed to meet National Grid and ENA (Energy Networks Association) requirements, the course covers the principles of insulated working, hazard recognition, and safe working practices to minimise risk when working on live circuits. Delegates gain practical awareness and competence to perform tasks safely on high-voltage substations, overhead lines, and cable networks while complying with statutory and company procedures.

This training is suitable for all personnel involved in projects near high-voltage infrastructure, including contractors, engineers, site operatives, and supervisors, and provides nationally recognised NSI5 equivalent certification.

This course is designed to provide guidance and best practice for those working on or in proximity to National Grid Electricity Transmission (NGET) assets, it references NGET procedures and industry practices to support understanding and application in the workplace. It is not an official NGET training course and is not endorsed by or delivered on behalf of NGET.

Course Duration:

One Day

Format:

In-Person

Location:

Stoneleigh Park

£1,250 +VAT

Certification Awarded

In-House Certificate

Valid for

One Year

Awarding Body

Who should Attend This Course

This course is suitable for:

HV/LV cable contractors working with systems under impressed voltage
Competent Persons seeking EUSR NSI‑5 endorsement
Site personnel involved in insulated working environments
Utility engineers and supervisors managing NV/LV cable sheath or accessories

Prerequisites

National Grid Competent Person Substations NSI 6 and NSI 8 and a good understanding of cable systems.

What To Have With You To Attend The Course

Photo ID

Assessment

Delegates will be evaluated through a combination of practical exercises, oral questioning, multiple-choice assessments, and written responses, ensuring a comprehensive understanding of the course material.

Course Content

Delegates will gain a thorough understanding of insulated live working principles and safe methods for managing impressed voltage risks.

Impressed Voltage

Purpose and scope of impressed voltage awareness
Definitions and key concepts
Dangers and potential consequences

General Requirements for Work on Cable Systems

Requirements for working on LV and HV cables
Principles for work under impressed voltage conditions

Specific Work Practices

Work on HV cable sheath disconnecting link boxes and link pillars under impressed conditions
Procedures for cable serving tests under a permit for work
Work on metallic cooling pipes under impressed conditions
Work on or near faulty or damaged HV and LV cables

Safety Procedures & Compliance

Application of insulated and earthed working protocols
Correct use of insulated PPE and tools
Permit processes, documentation, and supervision to ensure safe practice

Additional Information

Delivery Format: Instructor-led in-person training

Frequently Asked Questions

What is NSI 5 and why is it needed?

It covers hazards and safe work methods for cable systems under impressed voltage, essential for safe operation in live utility environments.

Is this course accepted by National Grid?

Yes, it aligns with National Grid’s NSI 5 technical guidance and is EUSR endorsed for contractors.

Who needs NSI 5 certification?

Contractors working on or near HV/LV cables under impressed voltage, especially where cables run alongside live overhead lines.

How often do I need to renew NSI 5?

Certification is valid for 1 year; a refresher required to maintain compliance

Specialist Cables & Impressed Voltage Safety

We work with Alcomet, a specialist supplier of electrical cables, earthing equipment and substation components. Their range includes IV Drain Earth leads, designed to help manage induced and impressed voltages and inadvertent backfeed in overhead line and substation applications. Alcomet’s specialist products complement our focus on safe working practices and impressed voltage awareness across the electricity industry.

Find out more about our partnership with Alcomet.

Discover Alcomet’s specialist cables and equipment.

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