In the relative humidity of close to 100% of the special humid places and corrosive gas or steam places should be used for protection. In the relative humidity is not more than 75%, and there is no dust, no corrosive gas or steam, no inflammable and explosive material is less dangerous place, the low-voltage distribution box can choose open type.
Distribution box in flammable liquid and suspended, piled combustible dust or combustible fiber H-1, H-2 fire danger place, should choose dustproof type; Optional protection type in h-3 fire danger place with solid combustible material. Dustproof distribution box should be selected in dusty places that can produce a large amount of dust.
