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. 2. 0mm thick cold-rolled steel plate, and those that are less than 600mm are made of 1. 2 mm thick. Guide Design and assembly according to IEC 61439 / EN 61439 ENYSTAR Distribution Boards up to 250 A and Mi Power Distribution Boards up to 630 A Download at www. Design requirements help you follow important standards like. to date & IS: 14772 / 2000 (amended upto date) for use in electrical distribution system in Mah rashtra. The system shall be AC three phase, four wires, 415 V, 50 Hz with effectively grounded neutral.