Exam Question

(a) Explain the term flameproof (Ex d) for electrical equipment:
The most common form of hazardous area electrical equipment is the flameproof enclosure type (Ex d) . The internal apparatus may include components that arc or have surfaces that become hot. Gas may also be present inside the enclosure, so it must fulfill the following three conditions:
The enclosure must be strong enough to withstand an internal explosion without suffering damage.
The enclosure must prevent the flame and hot gases from being transmitted to the external flammable atmosphere.