Electrical apparatus selected for the various hazardous locations
Zone 0 Ex “ia”, Ex “s”
Zone 1 Any type suitable for Zone 0 and Ex “d”, Ex “ib”, Ex “p”, Ex “e” & Ex“s”
Zone 2 Any type suitable for Zone 0 and Zone 1 and Ex “N”, Ex “o”, Ex “s”
Ex “d” Flame proof Enclosures designed to with stand an internal explosion of flammable gas or vapor with out suffering damage or allowing the gas or vapor surrounding the enclosure to ignite.
Ex “e” Increased safety apparatus designed in such a way so as to give increased security against the possibility of sparking or excessive temperature.
Ex “N” Non sparking similar in basic concept to Ex “e”
Ex “i” Intrinsic safe apparatus designed in such a way as to restrict the energy to a level below that which cause ignition.
Ex ‘p” Pressurizing, use of air or inert gas to maintain positive pressure to prevent the entry of flammable gas or vapor into the enclosure or room.
Ex “O” Oil immersed, ignition of flammable gas or vapor is prevented by immersion of live part of apparatus in oil.
Ex “q’ Sand filled, similar to oil filled, but the live part surrounded with sand or powder.
Ex “s” Special protection, this concept used to permit certification of designs and mentioned above.