As far as explosion-proof grades are concerned, they are all IIC grades, and the grades are the same; however, explosion-proof electrical equipment has a temperature group table, which is the maximum surface temperature of the equipment. The maximum surface temperature of T6 is not more than 85°C, and the maximum surface temperature of T5 is The maximum surface temperature of T4 does not exceed 100°C, and the maximum surface temperature does not exceed 135°C; IICT6 equipment can be used in places where IICT4 equipment is selected. This can be seen in the national electrical explosion-proof standard GB3836.1-2010, which is clear.

The positive pressure explosion-proof type achieves the purpose of safety by keeping the pressure of the protective gas inside the equipment shell higher than the pressure of the surrounding explosive environment. Types of positive pressure equipment protection include protection of static positive pressure inside the system, and continuous flow of air or inert gas to limit the entry of flammable mixtures into the interior of the enclosure.

Electrical equipment for explosive atmospheres

bT4 explosion-proof grade is B-level explosion-proof temperature group T4, the highest equipment surface temperature does not exceed 135 ℃, CT4 explosion-proof grade is C-level explosion-proof, explosion-proof grade can cover BT4 use, and can be used in dangerous places with hydrogen and acetylene.

The maximum equipment surface temperature of T4 does not exceed 135℃, T is the temperature group, T4 means that the equipment surface temperature does not exceed 135℃, and T6 has the highest safety level, that is, the lower the equipment surface temperature, the better.