Protection type "n": Slightly simplified application of the other zone-2 protection types – "n" stands for "non-igniting". (Standard EN 60079-15, IEC 60079-15).
Can be broken down into five categories: "nA" (protection against the risk of sparks or heat); "nC" (protected by a sealing envelope preventing penetration by an explosive atmosphere); "nR" (enclosures constructed to reduce the infiltration of gas); "nL" (using energy-limited circuits); and "nP" (maintaining pressure to prevent entry of any explosive gas).
Flameproof enclosure “d”: If an explosion occurs inside the enclosure, the housing will withstand the pressure and the explosion will not spread outside the enclosure. (Standard EN60079-1, IEC 60079-1, FM 3600, UL 2279 REPG).
Intrinsic safety “i”: By limiting the energy in the circuit, the formation of impermissibly high temperatures by electric sparks or arcs is prevented. (Standard EN 50020, IEC 60079-11, FM 3610, and UL 2279 REPG).