1. The equipment installed in the explosive environment of coal mine gas is divided into Ma class and Mb class:

Ma Level EPL Ma

It has a "very high" protection level that is safe enough to make it impossible for the equipment to operate properly, for expected or rare failures, or even to become a source of ignition in the event of a sudden gas occurrence where the equipment is still charged.

Mb EPL Mb

Has a "high" protection level that is safe enough to make it impossible for the equipment to become a source of ignition under expected failure conditions during normal operation or in the time between the sudden appearance of gas and the power failure of the equipment.

2, equipment installed in explosive gas environment is divided into Ga, Gb, Gc level:

Ga Class EPL Ga

Has a "very high" protection level and is not a ignition source during normal operation, expected failure, or rare failure.

Gb Level EPL Gb

Has a "high" protection level and is not a ignition source under normal operation or expected failure conditions.

Gc Level EPL Gc

With a "general" protection level, it is not a ignition source in normal operation, and some additional protection measures can be taken to ensure that effective ignition will not be formed in cases where the expected failure of the ignition source occurs frequently (such as the failure of a lamp).

3. Equipment installed in explosive dust environment is divided into Da, Db, Dc levels:

Da Level EPL Da

Has a "very high" protection level and is not a ignition source under normal operation, expected failure, or rare failure conditions.

Db Level EPL Db

Has a "high" protection level and is not a ignition source under normal operation or expected failure conditions.

Dc Level EPL Dc

With a "general" protection level that is not the ignition source during normal operation, additional protection measures can also be taken to ensure that effective ignition will not be formed in cases where the ignition source is expected to occur frequently (such as luminaire failure).

References: GB 3836.1-2021 Explosive atmospheres - Part 1: General requirements for equipment