Ga, Gb, and Gc are the protection levels for equipment used in explosive gas environments and are essential components of explosion-proof equipment labeling.

Equipment used in explosive gas environments with high levels of protection. During normal operation, expected or rare faults that occur are not ignition sources. Devices with Ga protection level can be used for Zone 0, Zone 1, and Zone 2

Equipment used in explosive gas environments with a high level of protection. Not a ignition source under normal operation or expected fault conditions. Gb protection level can be used for Zone 1 and Zone 2.

Equipment used in Gc explosive gas environments has a "general" protection level. In normal operation, it is not a ignition source, and additional protective measures can be taken to ensure that effective ignition will not occur in the event of expected frequent occurrences of the ignition source (such as lamp failure). Devices with Gc protection level can use Zone 2.

As is well known, the most dangerous area in Zone 0 can only adopt the equipment protection level of Ga, therefore, the equipment protection level of Ga is higher than that of Gb.