How to Install Electrical Boxes

Make sure to Account for the Finished Drywall When Installing Electrical Boxes

By Mark J. Donovan

When installing electrical boxes on wall studs or ceiling joists it is important to account for the thickness of the finished walls and ceilings when mounting them. Installing electrical boxes with pre-marked tabs or reference lines on them is helpful for ensuring that they are installed at the right depth on the wall studs. Make sure to buy switch and receptacle electrical boxes that meet both local and national electric codes. In addition, make sure to install electrical boxes of the right size and type for the specific application.

Electrical boxes have ratings stenciled on them for how many cable wires that can be brought into them. If more cables are brought into an electrical box than it is rated for there is the risk of broken and shorted wires.

Electrical Box Types

Non-metallic electrical boxes are the most prevalently used today by electrical contractors. They are both inexpensive and easy to install. In addition, unlike metal electrical boxes they do not have to be grounded.

Non-metallic electrical boxes are however a little flimsy and thus you have to be careful when nailing them to wall studs to not crack them. With some of the larger non-metallic electrical boxes it is wise to put some blocking behind them so that their front surface remains parallel and rigid.

Metal electrical boxes on the hand are rigid and can be ganged together. However metallic electrical boxes need to be electrically grounded and are more expensive.

Here is an electric bux for a light.

How to Install Electrical Boxes

To install electrical boxes, whether it be outlet electrical boxes or switch electrical boxes, make sure you mount them straight and level, and at the proper height per local and national electrical codes.

Many of the most common non-metallic electrical boxes come with nails already integrated into them and with reference installation depth lines or tabs on them. With these electrical box types all you need to do to install the electrical box is hold it in place so that it protrudes out to the finished wall thickness and nail it to the wall stud.

To install cables into an electrical box use a pair of lineman pliers or a screwdriver to knock out the necessary knock-out tabs and feed the cables into the electrical box. Make sure all ground wires associated with the incoming cables are tied together per local and national electric codes.

Finally properly strip and connect the black, red, and white wires to the electrical outlet receptacles and switches as specified by their particular manufacturers.

For help on building a new custom home, see’s New Home Construction Bid Sheet. The New Home Construction Bid Sheet provides you with the knowledge on how to plan a custom home building project, and what to look for when hiring contractors for your new home construction. It also includes a detailed cost breakdown table and spreadsheet for estimating your own new home construction building costs.

Related Information

Additional Electrical Wiring Resources from

Free Home Addition Price Quotes with No Obligation!

Fill out our 3-5 minute quick and easy form, and receive a free price quote on a house addition from one of our prescreened and licensed home addition contractors. This process is free and there is no obligation to continue once you receive your house addition price estimate.