The distribution box and switch box shall be made of iron plate or high-quality insulating material, and the thickness of iron plate shall be greater than 1. Associate Members are those principal companies involved in the direct supply to all or some embers of components, materials or products. Corporate Members are clients, professional offices, educational establishments etc, which support the development. Typical Thickness: These plates generally range from 1/2 inch (12. Material Strength: Temporary plates are often made from high-strength steel to ensure they. for lighting electrical distribution boxes and control boxes with a size greater than or equal to 600mm, 2. 5mm thick cold-rolled steel plates can be used. The gauge tells us how thick the metal is.