On formal explosion-proof electrical equipment, there will be an Ex mark, and each explosion-proof electrical equipment will have a uniqueExplosion proof signsTaking the following explosion-proof signs as an example:

Note 1: Ex is the explosion-proof symbol of China and the International Electrotechnical Commission, indicating that electrical equipment complies withGB3836One or more explosion-proof types listed in IEC60079

Note 2: Common symbols for various explosion-proof types are as follows:

Explosion proof type"D", increased safety "e"Intrinsic safety type"I", sand filled mold "q"Positive pressure type"P", immersion type "o", "n" typeexm"M"

The explosion-proof symbol in the example is for explosion-proof electrical equipment

Note 3: Equipment category symbol

(1) Class I: Electrical equipment for coal mines that are prone to producing gas

(2) Class IIA, IIB, IIC: Electrical equipment for explosive gas environments other than Class I, i.e. electrical equipment for factories

Note: IIB equipment can be used for the usage conditions of IIA equipment, similarly, IIC equipment can be used for the usage of IIA and IIB equipment; Condition, therefore, explosion-proof level IIC>IIB>IIA

Note 4: For Class II electrical equipment, the symbols representing temperature groups are as follows:

The highest surface temperature group of Class II electrical equipment

Note 5: The device protection level is divided into "Ga", "Gb", "Gc", "Ma" or "Ma".

Equipment Protection Level (EPL): The fixed protection level for equipment based on its potential as an ignition source and the different characteristics of explosive gas environments, explosive dust environments, and coal mine methane explosive environments.

——EPL Ma: Equipment installed in methane explosive environments in coal mines has a "very high" level of protection, which is sufficient in terms of safety to prevent the equipment from becoming a source of ignition during normal operation, expected or rare failures, and even in the event of a sudden gas appearance and equipment still being charged.

——Mb level (EPL Mb): Equipment installed in methane explosive environments in coal mines has a "high" level of protection, which is sufficient in terms of safety to prevent the equipment from becoming a source of ignition under expected fault conditions during normal operation or between sudden gas appearance and equipment power outage.

——Ga level (EPL Ga): Equipment used in explosive gas environments, with a "very high" level of protection, and is not a source of ignition during normal operation, expected failures, or rare failures.

——Gb level (EPL Gb): Equipment used in explosive gas environments, with a "high" level of protection, and is not a source of ignition under normal operation or expected fault conditions.

——Gc level (EPL Gc): Equipment used in explosive gas environments, with a "general" protection level. It is not a source of ignition during normal operation, and additional protective measures can be taken to ensure that effective ignition will not occur in the expected frequent occurrence of ignition sources (such as lamp failures).

——Da level (EPL Da): Equipment used in explosive dust environments, with a "very high" level of protection, and is not a source of ignition during normal operation, expected failures, or rare failures.

——Db level (EPL Db): Equipment used in explosive dust environments, with a "high" level of protection, and is not a source of ignition under normal operation or expected fault conditions.

——Dc level (EPL Dc): Equipment used in explosive dust environments, with a "general" protection level. It is not a ignition source during normal operation, and additional protective measures can be taken to ensure that effective ignition will not occur in the expected frequent occurrence of ignition sources (such as lamp failures).

According to the current national standard GB 3836.1-2010 "Explosive Atmospheres Part 1: General Requirements for Equipment", under the same conditions, electrical equipment with explosion-proof markings meeting the Ex d IIC T6 Gb standard shall have a higher explosion-proof level than electrical equipment with explosion-proof markings meeting the Ex d IIB T6 Gb standard.

For more information on explosion-proof certification, please contact Zhongnuo Testing directly

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