Ex e EN 60079-7 Explosive atmospheres.  Equipment protection by increased safety "e"

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:

• 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 Ex eb protection is used for just for terminals i.e. Junction boxes and occasionally motors or certain types of Luminaires, although it can be used for other simple electrical devices particularly for components such as sensors.

However, other than for junction boxes and terminals, it is generally used in conjunction with other protection methods such as Ex de and Ex em encapsulation which enables additional components to be used inside an Ex e enclosure or connected via Ex e teminals.

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.

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.

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