Electrical boxes come in many shapes and sizes. These boxes are used for outlets, switches, ceiling fixtures, junction boxes, and for keeping wires splices dry. Depending on the size and shape of the box, electrical boxes hold different amounts of wires. There are round, square, retangular, shallow, weatherproof, and extension boxes.
Electrical boxes come in plastic and metal varieties. Plastic boxes are non-conductive and are relatively inexpensive. They come in different styles that either nail on or are the cut-in variety. These cut-in boxes come equipped with wings that hold the box in place tightly against the drywall.
Metal or steel boxes are more durable than plastic boxes and some, like gangable boxes, can be joined to add more devices. These boxes are used in garages and basements where they are likely to be exposed and require more wear and tear traffic. Unlike plastic boxes that crack easily, metal boxes are built to last.
Switches and outlets use square and rectangular boxes. The square boxes use drywall rings that come in single-gang and double-gang varieties. The single-gang ring holds one device, while the double-gang ring holds two devices. Retangular boxes are specifically designed to accomodate a single device and has its own mounting brackets.
Weatherproof boxes are specially designed to keep water and moisture out. These boxes can be mounted outside in all weather conditions and have special covers that keep the wiring and devices dry inside.