Explosion-proof products each have an explosion-proof rating, which distinguishes the product’s type of explosion-proof design and applicable scenarios. For example, the explosion-proof rating Exd IIB T4 is explained in detail below.
Ex: Explosion-proof mark.
d: The type of explosion-proof is flameproof. There are also intrinsic safety types ia, ib; increased safety type e; oil-filled type o; sand-filled type q; encapsulated type m; and composite type (commonly used in explosion-proof distribution boxes).
II: Refers to the second category of explosion-proof electrical equipment. This category is suitable for explosive gas environments other than coal mines (Class I). There’s also Class III: Electrical equipment for explosive dust environments outside of coal mines. Class IIIA: Combustible fibers; Class IIIB: Non-conductive dust; Class III: Conductive dust.
B: Class IIB gas. There are also IIC and IIA. IIC is the highest level, applicable to IIA and IIB. IIB is suitable for IIA, but lower levels cannot use higher ones.
T4: The temperature class is T4, with the equipment’s surface maximum temperature below 135°C.
