On for example a chemical plant there may be present certain products that will ignite under certain conditions. As electrical apparatus can generate a spark and cause explosions steps have to be taken to prevent this. If something is explosion proof then it is contained within an enclosure which will withstand an internal explosion of a flammable gas or vapour that may enter it, without suffering damage and without communicating the internal flammation to the external explosive atmosphere, through any joints or structural openings in the enclosure. The enclosure will be designed for a particular gas grouping (I, IIA, IIB or IIC). This design concept is reflected in the equipment marking by the symbol ‘Ex d’. Equipment designed to this concept is suitable for use in ‘Zone 1’ and ‘Zone 2’ classified hazardous areas.
Powelectrics have developed an ATEX approved GSM / GPRS Telemetry device - the METRON ATEX.