Before installing an electrical box in your home, you should decide on its location. When installing the electrical box, make sure to choose one that is designed to withstand moisture, fumes, or both. 

For example, if you’re installing the electrical box in a paint shop, make sure you pick one that’s designed to withstand fumes. If you have multiple wires coming from the same location, multiply the number of wires you’ll need in the box by two. 

You can also multiply that number by 2.25 for a 12-gauge wire. For a more convenient way to determine how many wires you’ll need to plug into your outlet, consider the largest ground wire.

When choosing an electrical box, keep in mind the type of wiring and devices you’ll be installing. Choosing the right box for your home will help you avoid a dangerous electrical fire. 

It’s best to choose a rectangular box for your outlets and wall switches, as these are the most common. For multiple devices, however, you should opt for square boxes, which have more space to accommodate wiring connections. 

How Do I Choose an Electrical Box?

There are many different types of electrical boxes available. You’ll find them in the round, octagonal, standard, and nonmetallic varieties. Before you buy one, it’s helpful to know the features of each type. Read this article to make the best choice. 

• Styles

Electrical boxes come in several styles. You can find small rectangular boxes for single light fixtures or medium-sized ones for standard power outlets and telephone jacks. Rectangular boxes typically have dimensions of 2″ x 3″ and a depth of 1.5″ to 3.5″. Many rectangular boxes are gangable, which means you can install several of them instead of having to choose one for each location. 

• Type of Box

If you are building a new house or renovating an existing one, you’ll want to consider the type of electrical box you’re going to use. Some are square, and other types are portable, weatherproof, or floor-mounted. A standard rectangular electrical box can be either metal or plastic. In either case, it will protect the wiring from the elements. If you have more than one outlet, you may want to choose a double-gang box. 

• Material

When choosing an electrical box, you have several options. You can get nonmetallic boxes made of PVC, aluminium, fibreglass, or cast aluminium. A metal box is usually a better choice for installations that are exposed to the elements. Its design can accommodate both metallic and nonmetallic cables and is more durable than its plastic counterpart. Plastic electrical boxes are generally easy to install and can be concealed behind drywall. Metal electrical boxes are the safest option for exterior installations, however.

• Size

The size of an electrical box is determined by the total cubic inches of its interior space. A single or double gang box should contain 18 cubic inches of space. The volume should be at least equal to the size of the wiring and electrical components contained inside it. A new nonmetallic box should come with this information, but most will not.