Metal Back Boxes

A double metal back box is a two-gang steel box sized for a double socket or a two-gang switch plate. Flush versions are set into the wall, while surface versions fix to the face of the wall. Match the depth to the accessory. The range here includes double flush boxes in several depths and a double metal clad box.

A 35mm metal back box gives a common flush depth for standard sockets and switches, with room behind the plate for the cable terminations. Shallower boxes can suit thin walls and simple switches, while deeper boxes suit bulky accessories or extra cables. The range here includes single, double and dual-plate galvanised boxes at this depth.

A metal clad back box is a steel box fixed to the surface of a wall, made to carry metal clad switches and sockets where cables run on the surface. It is tougher than a plastic surface box, so it suits garages, workshops and plant rooms. Check the IP rating, since many are made for indoor use. The range here includes single, double and grid metal clad boxes.

Yes. A metal back box must be connected to the circuit's protective earth, usually with a short earth lead linking the earth terminal on the accessory with the terminal in the box. This keeps the metal safe if a live conductor ever touches it. Look for a box with its own earth terminal. The range here includes galvanised steel boxes with a built-in earth terminal.

A metal back box is a steel box that houses the wiring behind a switch or socket and gives the faceplate screws a firm fixing. Flush types are set into masonry walls, and surface types fix to the face of the wall. Steel boxes are tough and usually carry an earth terminal. The range here includes galvanised flush boxes, extension boxes and metal clad boxes.