On explosion-proof grade of explosion-proof distribution box

Talking about the explosion-proof grade of explosion-proof distribution box

An explosion-proof distribution box will have an explosion-proof rating. What is the meaning of explosion-proof grade?

Explosion-proof mark: ExdeIIBT6

Ex means explosion-proof. d stands for flameproof type; e stands for increased safety type; II refers to the category of electrical equipment. (Electrical equipment for explosive gas environments other than coal mines) B refers to the group of explosive gas mixtures, IIA, IIB and IIC are classified according to the maximum test safety clearance or the minimum ignition current ratio. See the table below for details. T6 refers to the high surface temperature group of electrical equipment.

The specific difference of the explosion-proof form:

The flameproof type is marked d

Explosion-proof principle: When the equipment is in normal operation, the parts that may generate sparks or arcs are inside the flameproof enclosure. The flameproof enclosure can withstand the pressure of the internal explosion without causing damage, and can ensure that the flame and heat generated during the internal explosion pass When the flameproof joint surface is extinguished and the temperature is reduced, it is not enough to detonate the explosive gas outside the shell; Applicable area: Zone 1, 2 GB3836.2

Increased safety sign is e

Explosion-proof principle: During normal operation, no arc, spark or dangerous high temperature will be generated, and further protective measures will be taken on the structure to improve the safety and reliability of the equipment. Applicable areas: Zones 1, 2 and GB3836.3

Intrinsic safety symbol is I

Explosion-proof principle: The circuit inside the equipment is under specified conditions. The sparks and thermal effects generated under normal operation or specified fault conditions cannot ignite explosive gases. Applicable area: Area 0, 1, 2 GB3836.4

Positive pressure shell type symbol is p

Explosion-proof principle: keep the pressure of the internal protective gas higher than the surrounding atmospheric pressure to prevent the explosive gas from entering the enclosure, or allow a sufficient amount of protective gas to pass through the enclosure, so that the concentration of the explosive gas within the lower limit of the explosion below; GB3836.5