Explosion-proof grade difference

Explosion-proof equipment definition: Electrical equipment that does not cause the surrounding explosive atmosphere to ignite under specified conditions.

Divided into two categories

Category I: Coal mine underground electrical equipment;

Category II: Electrical equipment for all other explosive atmospheres except coal mines and downholes.

Class II can be further divided into Classes IIA, IIB, and IIC. Devices that mark IIB can be applied to the conditions of use of IIA equipment; IIC can be applied to the conditions of use of IIA and IIB.

Note: The IIC mark is a higher explosion-proof rating, but it does not mean that the device performs best.

Maximum surface temperature: The maximum temperature reached by any component of an electrical device that may cause ignition of the surrounding explosive atmosphere when the electrical device is operating under the most unfavourable operating conditions within the specified range. The maximum surface temperature should be lower than the flammable temperature.

For example, the ignition temperature of an explosive gas in an explosion-proof sensor environment is 100°C, then the highest surface temperature of any part of the sensor under the worst working conditions should be less than 100°C.