ABSTRACT
This chapter focuses on the manufacturing side of the business alone and in particular to the avoidance–through proper electrical safety measures–of explosive risk to both plant and personnel. “Explosion-proof” and “Flameproof” are two very different concepts as far as design specification and manufacturing construction is concerned. Shunt diode barriers are usually mounted in the safe location, although they can be mounted in the hazardous location, provided only that they are contained in an enclosure that is flameproofed or pressurized to Zone 1 requirements. Galvanic isolators, provide a signal path between devices in the safe and hazardous locations without a direct physical connection between the two. The grounding system must include all power available at a site–i.e., distribution, lighting, equipment and accessories power, instrumentation, and signaling equipment. Common-mode voltages are those that appear equally on each side of a signal line pair to a common reference point, which is usually the system ground.
