Electrical safety of process instrumentation in areas with potentially explosive gas atmospheres

Many European installation rules (including DIN 57 165/VDE 0165, BS 5345, NE 3410) on electrical systems in areas with potentially explosive gas atmospheres are generally in line with the recommendations of publication IEC 79-14 with regard to selection of the recommended type of protection. These recommendations also apply to electronic process instrumentation. Process instruments are often unavoidably in contact with this atmosphere so they must be contained. The author looks at the safety of these instruments