Q-1 level places that can form explosive mixture under normal conditions shall select explosion-proof, explosion-proof ventilation and inflatable low-voltage distribution box.

(1) In places with explosive mixtures of gases or vapors

① Q-1 level places that can form explosive mixture under normal conditions shall select explosion-proof, explosion-proof ventilation and inflatable low-voltage distribution box.

② Any type of explosion-proof type can be used in Q-2 level places where explosive mixture can not be formed under normal conditions and can be formed under abnormal conditions.

③ It can not be formed under normal conditions, but it can form explosive mixture under abnormal conditions, but it is less likely to form q-3 level places, so sealed type can be selected.

(2) In places with explosive mixtures of dust or fibers.

① In a class g-1 place that can form explosive mixture under normal conditions, any class of explosion-proof type, explosion-proof ventilation type and inflatable type can be selected.

② For class G-2 places that can not be formed under normal conditions and can only form explosive mixture under abnormal conditions, dust-proof type can be selected.