The fire-proof high-voltage distribution room of distribution box shall be of class I and II fire-resistant buildings. The fire resistance rating of LV distribution room shall not be lower than level III. The windows of the power distribution room shall be provided with waterproof, rain and snow proof measures to prevent small animals from entering. When the high and low voltage power distribution devices are in the same room, the distance between them shall not be less than 1 m.

Selection of fuse for distribution box. The rated current of the total overcurrent protection fuse at the low-voltage side of the distribution transformer shall be greater than the rated current at the low-voltage side of the distribution transformer, generally 1.5 times of the rated current, and the rated current of the melt shall be determined according to the allowable overload multiple and fuse characteristics of the transformer.