Therefore, the thickness of the sheet metal of the cabinet body of the power electrical distribution box is usually not less than 1. 0mm or thicker, may be. Requirements for concrete enclosures, required when installing a secondary enclosure in an area subject to vehicular traffic. In no case shall the volume of the box, as calculated in 314. Their dimensions are generally around 2 inches wide by 4 inches tall, with depths varying from 1-1/2 inches to 3-1/2 inches. Just like travelers need clear pathways and safety protocols, your electrical circuits need proper management to prevent chaos. 5mm thick cold-rolled steel plates can be used.