Ex e EN 60079-7 Explosive atmospheres.  Equipment protection by increased safety "e"
Type of protection applied to electrical apparatus in which additional measures are applied to give increased security against the possibility of excessive temperatures and of the occurrence of arcs and sparks in normal service or under specified abnormal conditions.

Ex eTriangle Increased safety Ex e requires a high integrity of components, removing the ignition the ignition source, i.e. no potential sparking components. The internal temperature of the components is critical (which is different from Ex d where it was the external enclosure temperature which was assessed).

The main features are: Ex e Enclosure

  • No ignition sources, i.e. No sparking contacts
  • High Integrity connections
  • Good Mechanical Protection (Impact)
  • IP 40 if fully insulated live parts otherwise IP 54 (in most cases) i.e. not gas tight
  • Certified components must be used internally

Generally an Ex e assembly is used for just for terminals i.e. Junction boxes.

There are two protection levels Ex eb and Ex ec for Zones 1 and 2 respectively, older equipment will just be labelled Ex e covering both Ex eb and Ex ec.

Category Zone of use
Ex ec 3 Zone 2 See Ex nA
Ex eb 2 Zone 1 Conventional Ex e

The only real use for the older Ex e and Ex eb assemblies is junction or terminal boxes, although historically other components have had Ex e certification these have largely disappeared from the market leaving just terminals.
However, Ex e is often used in conjunction with another protection technique such as Ex de and Ex em encapsulation which enables additional components to be used inside an Ex e enclosure

Ex ec

This does allow a lot more flexibility than Ex eb, as it allows Ex nA and Ex ec internal components for a built solution using components other than terminals. The intention is it will completely replace the Ex nA protection method but not for some time yet.

Dust

Although older equipment has Ex e certification for dust, usually where the ambiguous 'GD' was often used. Modern certifications use Ex t as the easier protection method for dust.

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