Exam Question

(a) Intrinsic electric safety (IS) is a protection technique applied to electrical equipment and wiring used in hazardous areas. Its core principle is to prevent ignition of flammable atmospheric mixtures—such as gases, vapours, or dusts—by limiting the electrical and thermal energy available in the circuit to levels below those required for ignition.
This ensures that any sparks or hot surfaces produced by the equipment, even under fault conditions (e.g., short circuits, open circuits, component failures), cannot ignite the surrounding atmosphere.
Key characteristics of intrinsic safety:
Energy Limitation: Voltage and current are strictly limited using components such as resistors, Zener diodes, and fuses.