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Hazardous Area Electrical Equipment - Technical Guide

Hazardous Area Overview

A hazardous area is an area where flammable liquids, vapours, gases or combustible dusts are likely to occur in sufficient quantities to cause fire or explosion. Industries such as metalliferous mining, oil and gas infrastructure, automotive refuelling stations, chemical processing plants, printing industries and cement works often have hazardous applications.

There are three basic conditions that must be satisfied to create a fire or explosion:

Ex triange

  • Flammable or combustible material - such as flammable liquid, vapour or combustible dust must be present in sufficient quanity and concentration.
  • Oxygen
  • Ignition source

Hazardous area electrical quipment works by suppressing or separating one or more of these three components to avoid a fire or explosion.

Ignition Sources

The following ignition sources have the potential to cause an explosion in the right circumstances:

  • Electric arcs and spark
  • Flames
  • Hot surfaces
  • Electrostatic sparks
  • Thermite sparks
  • Mechanical friction
  • Mechanical sparks produced by grinding
  • Smouldering deposits
  • Compression ignition
  • Electromagnetic radiation
  • Chemical reactions
  • Ultrasonics

IEC Standards & Certification

IEC Ex is an internationally recognised scheme for the certification of hazardous area electrical equipment. The IEC Ex system is designed to facilitate internation trade in equipment and services for use in hazardous areas, while maintaining the required level of safety.

Required Information

There are 4 important pieces of information required when selecting equipment for hazardous areas:

  • Zone Classification
  • Gas Group
  • Temperature or T Rating
  • IP Rating


B&R Ex Systems recommends the undertaking of hazardous area training for any persons involved in the installation and maintenance of electrical equipment for hazardous areas. Optec is a registered training organisation offering a variety of courses to proessionals in hazardous area industries. These courses are held regularly at B&R offices regularly.

For more information visit

Useful Links

This website is for the Internation Electrotechnical Commission System for certification to standards relating to equipment for use in explosive atmospheres.

Showcases the entire B&R Ex Systems range. It is continually updated as new products are released and is the best source of information on B&R Ex Systems products.

Showcases the entire B&R Enclosures range of products including industrial, data & communications, multiple application, climate control & hazardous area equipment.

Optec are a leading provider of training and consultancy services to the energy & allied industries. The consultancy services offered include the preparation of statements of conformity & audits, design, risk assessment and hazardous area wiring dossiers.

Ex e Enclosures

Ex e Enclosures

A range of Ex e rated, increased safety enclosures suitable for hazardous locations. These include sloping roof, hinged roof and screwed lids designs.

Ex d Enclosures

Ex d Enclosures

A range of Ex d rated aluminium enclosures suitable for flameproof applications. Round, square and larger rectangular enclosures are available.

Hazardous Area Lighting


A range of lighting for hazardous area locations includes IEC Ex certified fluorescents, well glass lights, floodlights and LED lights, rated to Ex d, Ex n and Ex e.