Differenceof explosion-proof levels

- Jun 10, 2020-


Definition of explosion-proof mark

Explosion-proof mark refers to the mark used to describe the explosion-proof level, temperature group, explosion-proof type and applicable area of explosion-proof electrical equipment.


Explosion mark requirements

Explosion-proof electrical equipment must have a clear permanent convex mark "Ex" in the obvious place. Small equipment can be welded on the casing with a sign plate or marked with a concave mark.

The nameplate of the equipment casing must be clearly marked and firmly fixed. The nameplate should have the following contents: an obvious “Ex” mark on the upper right; an explosion-proof mark indicating the type, category, level, temperature group of the explosion-proof in order; Numbers and other special conditions that need to be marked, as well as the date of manufacture or product serial number.


(Q & A)


1. What are the parts of China's explosion-proof signs? Explain their meaning separately?


Explosion-proof mark generally consists of the following 6 parts:

① Explosion-proof mark EX—indicates that the equipment is explosion-proof electrical equipment;

② Explosion-proof structure form—Indicate what measures the equipment adopts for explosion-proof, such as d is flameproof type, p is positive pressure type; i is intrinsically safe type;

③ Explosion-proof equipment categories-divided into two categories, I is the electrical equipment used in coal mines, and II is the electrical equipment used in factories;

④ Explosion-proof level-divided into three levels of A, B, and C, indicating the strength of its explosion-proof ability;

⑤Temperature group—It is divided into six groups T1 ~ T6, indicating the allowable high surface temperature of the device.

⑥ Equipment protection level: Ga, Gb, Gc.


2. The explosion-proof mark of an instrument is EXdIIBT4 Gb, please explain its meaning.


Answer EX-General mark of explosion-proof;

d——structure form, flameproof type;

II——Category, for factory use;

B——Explosion-proof level, B level

T4——temperature group, T4 group, the highest surface temperature is ≤135 ℃.

Gb-equipment protection level Gb.