The EX on the electrical plan is the text marking of the explosion-proof power socket, see national standard GB09DX00. The explosion-proof marking means that there is an explosion inside the electrics, and there will be no sparks to the outside. Coal mine electrical mostly use this type. Generally and IB (on behalf of the product within the intrinsically safe system) is accompanied by intrinsically safe. Means safer.
Explosion-proof marking on the electrical plan generally consists of the following five parts:
Explosion-proof marking EX-indicates that the equipment is explosion-proof electrical equipment.
Explosion-proof structural form - indicating that the device uses what measures for explosion-proof, such as d for the explosion-proof type, p for positive pressure type; i for intrinsically safe.
Explosion-proof equipment category - divided into two categories, I for the coal mine underground electrical equipment, II for the factory electrical equipment.
Explosion-proof level - divided into A, B, C three levels, indicating the strength of its explosion-proof capability.
Temperature group - divided into T1 ~ T6 six groups, indicating the maximum surface temperature of the equipment allowed.
For example: a meter explosion-proof mark for EXdIIBT4, the meaning of: EX - explosion-proof general sign; d - structural form, explosion-proof; II - - category, factory use; B - B - - category, factory use; B - - the temperature group - is divided into T1 ~ T6 six groups, indicating that the maximum allowable surface temperature of the device. - category, factory use; B - explosion-proof level, class B T4 - temperature group, T4 group, the maximum surface temperature ≤ 135 ℃.