The width of the electrical box is 40MM, the height is 40MM plus the switch height, and the depth is 10MM plus the maximum switch depth. We have the solution to all of your onsite needs with our 20" Distribution Box! This box is great for large or small applications. No other box allows you to choose where to set your inlets or outlets. There's no need to worry about different colored fittings or plugs to inventory because as well. Electrical box dimensions typically refer to: Correct dimensions ensure: Single-gang boxes are the most common type, used for one switch or outlet. Picking the right size helps you stay safe, follow. Freestanding enclosures are designed to house taller equipment and larger back panels, often used in industrial control or power distribution systems. Dimensions included are length, width.