June 15, 2023

As a homeowner, you constantly have to take care of new things that pop up and need your attention. Sometimes, taking care of them requires a little learning. For instance, you might have to do some research if you want to install a new wall switch or power outlet.

As a part of that learning, you’ll come across electrical boxes. To help you, here’s a quick crash course on everything homeowners need to know about electrical boxes.


What They Do


Why does anyone even have an electrical box in the first place?

Electrical boxes serve a couple of specific and essential functions.

First, they protect junctions in wiring. That might sound a little technical, but anytime you connect something to the wiring in your home, there is a junction. Here’s an example to clarify. Say you have a ceiling fan with a light attached to it. You can turn on the light and/or fan via a switch on your wall. If you take the switch cover off, you’ll see wires, the switch device, and an electrical box. In order to connect the switch (and ultimately the fan) to your house’s wiring, you have to physically attach wires from the fan to the switch along with wires from the house. These attachments require exposed leads, so you have wires, hot with electricity, that are exposed in order to connect everything. Your electrical box is there to protect those exposed parts to prevent electrical and fire dangers.

Second, electrical boxes stabilize your wiring. Since everything has to connect via exposed wires at some point, you have a bunch of “joints” that are vulnerable. Any outside force could easily separate these joints. Your electrical boxes prevent anything from having the chance to separate the wires and create problems. In other words, the boxes keep the lights on.


When You Need a New One


As a homeowner, you might need an electrical box from time to time. In theory, all of the electrical joints already had boxes when you bought the house, but there are two times when you might need a new box.

The first is easy to understand. If you install something that creates a new joint (like adding an outlet to the wall in a convenient location), then you need to add a box to protect that joint. Realistically, you probably need a qualified electrician to add the box, since many states, counties, and cities have strict regulations around electrical work.

The second time you might need a new electrical box is when an old box has problems. This can happen in a few ways. You might do some renovations and accidentally damage an electrical box. An old box might just wear out over time (although this is relatively uncommon). Regardless, if an existing box can no longer protect your wire joint, it needs to be replaced.


How to Pick the Right Box


Assuming you need a new electrical box, you might want to know how to get the right box. This can be broken into three shopping considerations.

Let’s start with the material. Technically, a home can use a number of different materials (depending on your local wiring codes), but inside a home, plastic boxes are the most common. They also cost less, so this is a good place to start.

Once you pick a material, you need the right size. The box has to be big enough for every joint inside of it. A single switch is easy to size, but if you’re going to put a light/fan system on a five-switch plate, you’ll need a bigger box. If you’re not sure how to size a box, consult an electrician.

Lastly, you need to think about the adjustability of the box. Typically, electrical boxes are pre-formed, and they can adjust or change once you buy them. But, there is a category known as adjustable boxes. These allow you to adjust the box’s depth relative to the wall.

To clarify this, if you have something beyond your drywall, like paneling or wainscoting, then to get the box to sit flush, you’ll need an adjustable box. They’re available for sale when you pick everything else. If you don’t need the adjustment, static boxes are usually a little cheaper.