Electrical Testing
Wiring Device Box Mounting Basics

Wiring Device Box Mounting Basics

Doing a good job installing receptacles (and being quick about it).

If only someone gave you a nickel for every poorly installed receptacle you’ve seen. Wouldn’t that be a windfall? Think of how many times you’ve seen a receptacle that was crooked. Maybe you’ve even seen a faceplate screwed on so tightly it was bent inward toward a receptacle that was clearly too far back in the box.

Photo credit: Stockbyte/Thinkstock

In really bad cases with dual receptacles, the top socket is sticking way out past the faceplate, and the bottom one is sunken back in behind it. And you’ve seen other cases of poor workmanship, such as a loose faceplate. The root cause of these problems is nearly always an incorrectly mounted 2x4 box behind the receptacle.

Let’s start with how to mount that box, assuming it’s new construction. With wood frame structures, the fact the box is typically nailed (or screwed) to a wooden stud is where the trouble begins. How can you reliably place that box in the correct position in three dimensions?

Easy. Look at the box. You’ll see depth guides right on it. If you don’t see those, it’s a cheap box that you don’t want to use; replace it with a box that has these guides. Look at your boxes when buying them to ensure they have this feature.

If you mount the box using these guides, the front of the box will be just about flush with the drywall. Not only that, the box will be mounted squarely in all dimensions. That is, if you hold the box in position using the guides, you’ll keep the box from leaning back, tilting to one side, sticking out, or being too far back.

What if someone else mounted the box and did a bad job? And now the drywall is in place? This pretty much rules out correcting the position of the box. Don’t try to make up for this with creative “adjustments” of the faceplate. You do have a little leeway with the faceplate, but the operative word is “little.”

Here’s one “trick” that leaves a dangerous installation. Leave the mounting flange screws loose so that you can pull the receptacle tight to the faceplate. Now the receptacle is basically clamped to the drywall using the faceplate. Can you see the problems with this “solution?”

The root error is nearly always that the box is too far back (or crooked). This is fortunate, because there are easy solutions for that problem.

Receptacles come with adjustment tabs on the top and the bottom of the mounting flange. You can use these to try to correct for the box installation. Note how much offset there is before doing anything with those tabs. An even better option is to have a package of receptacle mounting spacers. That’s right — there’s a product made just for this problem. The spacers go on the mounting screws (between the box and the mounting flange). Just eyeball how many you need, put them on, and presto!

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