Indoor electrical distribution box wall thickness

Indoor electrical distribution boxes typically have wall thicknesses of 1/16 inch (≈1.6 mm) for metal boxes and up to 1/8 inch (≈3 mm) for plastic boxes.Metal BoxesMetal electrical boxes, commonly made from stamped sheet steel, usually feature thin walls around 1/16 inch (1.5–1.6 mm). This thickness provides sufficient structural strength while maximizing internal volume for wiring and devices. Metal boxes are often shallower than plastic boxes but allow for precise wire placement and easier installation of stiff conductors, such as 12 AWG solid wires, without compromising safety .Plastic BoxesPlastic (PVC or polycarbonate) boxes generally have thicker walls, up to 1/8 inch (≈3 mm), to maintain rigidity and durability. The thicker walls help prevent cracking during installation and provide reinforcement for mounting screws and connectors. Plastic boxes may also include internal ribs or rounded corners, which slightly reduce usable internal space but improve structural integrity .ConsiderationsInternal Volume: Wall thickness affects the internal volume of the box. Thicker walls reduce usable space, so it's important to verify the internal cubic inches when planning for multiple wires or devices .Device Depth: Modern smart switches, GFCIs, and USB outlets often require deeper boxes. Choosing a “deep” version compensates for thicker walls and ensures proper device fit .Standards Compliance: While wall thickness is not universally standardized, manufacturers design boxes to meet NEMA or IP ratings for indoor use, ensuring adequate protection and mechanical strength .SummaryFor typical indoor electrical distribution boxes:Metal boxes: ~1/16 inch (1.5–1.6 mm) wall thicknessPlastic boxes: up to 1/8 inch (≈3 mm) wall thickness Always check the manufacturer's technical drawings to confirm wall thickness, internal volume, and compatibility with the devices you plan to install .