Chapter 1:
Purpose and Scope

1.1 What is the purpose of this guide?

This guide is a practical risk assessment tool for the European Engineer, which is primarily designed to evaluate and manage dangerous levels of arc flash incident energy in electrical distribution systems.

It is clear from the European Council Directive 89/391/EEC (EU Workplace Health and Safety Directive) that there is an obligation on behalf of the employer to assess levels of risk involved in the workplace and the effectiveness of the precautions to be taken. For electrical work, this should include all the hazards of electricity, including the arc flash hazard, and not purely shock, as is often the case. A key element of risk assessment for electrical work is that hazards are identified and evaluated as part of a decision-making process, beginning with the justification for working on or near energised equipment.

A major objective of this guide is to provide the predictive tools to determine the arc flash hazard severity and the means to prevent it causing harm. For hazard severity, the guide provides calculators and tables to assist engineers in evaluating the magnitude of the arc flash incident energy – the first step in the risk assessment process. Whilst simple in nature, the calculators are also accurate to the extent that they are based upon the latest research. Where requirements for assessment are more complex in nature, then there is guidance on how to approach the subject of outsourcing system studies and the choices of software for modelling complex electrical engineering systems. There are several advantages to using the guide which are:

  • The guide will identify significant risks quickly.
  • It will provide scalability, flexibility and be a steppingstone to a more complex approach, should it be necessary.
  • It is a very low cost and accessible alternative and inclusive of more members of the engineering team.
  • It can easily be adopted into dynamic risk assessments.
  • Easy “What if” scenarios for those times when the accuracy of input data is questionable.
  • It provides a source of awareness, training & information which is in my view the biggest step change that duty holders can make.
  • The guide is web based as well, so updates to standards and legislation will allow the reader to be kept up to date.
  • Information is provided in developing a strategy for managing the risk.
  • In depth information for carrying out complex system studies. This includes planning and pitfalls as well as information on the protective relays that may be encountered.
  • There is benefit of years of shared practical experience throughout and there is a separate section on arc flash myths and mistakes.
  • Use of the guide will reduce costs through:
    • Low Initial cost of the guide with associated calculator tools and accompanying tables. This is deliberately based upon the strategy of making the advice as accessible as possible.
    • Optimising PPE by taking the reader through a process of practically avoiding or reducing the risk which will often lead to more comfortable and less expensive solutions.
    • Complex software and training costs are expensive, so the use of this guide is not only highly beneficial in other ways but extremely cost effective as well.
    • Cost reduction strategy, commercial contracts, and vendor advice should a more complex approach be required.
    • Identify and group low level circuits into categories that can be excluded from complex arc flash studies.