Dust explosion-proof electrical equipment a and b type difference

There is no conflict of principle between Type A and Type B, just different methods adopted by different equipment to achieve the purpose of protection.

Firstly, both Type A and Type B are specified according to tD, which is the enclosure protection in dust protection

Secondly, Type A needs to be tested for the level of protection: the dust-tight enclosure, IP6X, can be used in Zone 20, Zone 21, or in Zone 22 with conductive dust, and the dust-tight enclosure, IP5X, can be used in Zone 22 with conductive dust

Type B needs to be analyzed in terms of the width of the explosion-explosion-proof mating surfaces and the clearances.

The two types of protection provide equivalent protection.

Specific parameters are given in IEC 61241-0 (general standard) IEC 61241-1 (enclosure protection tD)