What Size Box Is Required For Indoor Illumination In A Household Setting? Shallow pancake boxes (4 in. deep) are commonly used for flush-mounting light fixtures, while 4S deep boxes are suitable for installing GFCI receptacles or needing more room for. Choosing the correct electrical box dimensions is essential for safe wiring, code compliance, and long-term reliability. This. Many renowned manufacturers today provide relevant technical specifications for their luminaires online. These specifications, which are subject to permanent innovation due to rapid developments in LED technology, can be kept up-to-date. connected load, luminous efficacy. Electrical enclosure sizes are not universal, but most manufacturers follow common size families. This guide explains typical wall-mount and floor-standing dimensions, how to read catalog sizes, and how to choose the right enclosure size for your layout. Common enclosure sizes range from compact wall-mounted boxes to. Boxes and Covers for Electrical Systems include the following product types Pre-fabricated Metallic Boxes and Assemblies Steel Outlet and Switch Boxes, including: 4" Steel Square Boxes 4-11/16" Steel Square Boxes 5" Steel Square Boxes Utility (Handy) Boxes Switch Boxes Gang Boxes Masonry Boxes.