Electrical Equipment in Hazardous Locations

Equipment selection

For every zone of an installation with an explosive atmosphere, electrical equipment must be selected with a matching type of protection (e.g. flameproof enclosure, intrinsic safety, increased safety), equipment category and temperature class. The assignment follows from the installation’s zone plan and explosion protection document; it is the precondition for a device not becoming an ignition source itself during normal operation and expected malfunctions.

Maintenance and inspection

Unlike conventional electrical installations, a correct initial selection is not sufficient on its own: enclosure seals, cable entries and terminal connections of Ex-rated equipment must be checked recurringly under a graded regime of visual, close and detailed inspection, since even a loosened fastener or a damaged gasket can defeat the type of protection. Repairs and spare parts must only be carried out by suitably qualified personnel using components approved for the relevant type of protection.

Insurance relevance

During technical risk surveys of installations with explosive atmospheres, insurers specifically check whether the installed electrical equipment matches the current zone plan and whether a documented inspection and maintenance regime is followed. Uncertified, outdated or improperly repaired Ex-rated equipment is regarded as a serious deficiency with a direct bearing on explosion hazard.