Buying Guide

Types of Electrical Boxes

Types of Electrical Boxes
An electrical box being installed.

Specific boxes are designed for use indoors or outdoors, while others are made to be installed behind or outside of walls. 

  • Handy Box: Mounts on the surface of a wall. Can contain light switches or receptacle Ideal for areas where behind-the-wall installation is difficult or not possible.
  • Junction Box: Wires connect only to each other, never to a switch, receptacle or fixture. Allows circuits to be safely split and branched into different directions.
  • New Work Box: Installed as part of a new construction project. Mounts directly to studs or joists, or placed between two studs using a bar hanger before drywall is applied.
  • Old Work Box: Also called “remodeling box.” Designed to be installed on drywall after it has been hung. Has clamps built into the box and is ideal for adding new outlets to pre-existing walls.
  • Outdoor Box: Available in metal and nonmetallic units. Protects wiring from the elements with gaskets, sealed seams and watertight covers.

Tip: Electrical code requires that all electrical boxes be fitted with box covers. Exterior covers need to be watertight.

Electrical Box Shapes and Sizes
Two different electrical boxes.

The shape of an electrical box can help you identify its purpose.

A standard rectangular shape is the most common electrical box. This unit houses a single electrical switch or outlet available in metal and nonmetallic units that protect wiring from the elements with gaskets, sealed seams and watertight covers.

A square electrical box, also known as a “double-gang box,” houses two devices, either a combination outlet/switch or pair of outlets/switches in one location

The round or octagonal box houses lightweight fixtures or safety devices in ceiling such as a light or smoke and carbon monoxide alarms.

A ceiling box is used for heavier fixtures, such as ceiling fans or chandeliers. Be sure to choose a ceiling box that is specifically designated to support extra weight.

Electric Box Materials
A metal box on the left, a plastic/pvc box on the right.

Electrical boxes are constructed of either metallic material, such as aluminum, steel or cast iron, or nonmetallic material, such as PVC or plastic. 

Metal Boxes: 

  • Many local building codes require metal junction boxes because they are durable and ensure long-lasting performance 
  • Should be used for exposed indoor applications, such as with conduit in an unfinished basement

Plastic or PVC Boxes: 

  • Inexpensive, easy-to-install 
  • Can be placed behind drywall 
  • Should only be used with nonmetallic cable
Electric Box Installation Tips and Tricks
Man installing an electrical box.

Always check with your local building inspector before starting any electrical project to ensure that you are following code. 

  • For new construction installations, diagram the room and be sure you have enough electrical boxes to accommodate all the light switches, outlets and fixtures you need.
  • When working in finished areas, use a stud finder to locate studs and make sure they don't interfere with the placement of a new box.
  • Trace an outline of the box on the wall where it will be installed to mark cutting lines. Utility knives work well for cutting holes in drywall, keyhole saws are good for plaster, and saber saws are useful for wood.
  • Light switches are generally installed about 42 inches from the floor.
  • Power outlets are generally installed 12 inches from the floor.
  • Plan for future changes by clearly labeling all wires.

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