Electrical Boxes: How to Add Capacity

Two ways to solve this common remodeling problem

If you're adding wires or a bigger device to an electrical box, you may need additional capacity. There are two ways to enlarge an existing box without tearing the wall open.

By the DIY experts of The Family Handyman Magazine

Make room for a new device

Although your current electrical “box fill” may meet code, it’s not safe to jam a new device in if the box is already full of wires. You have two options: Add a plastic surface-mount extender box (like Leviton No. 6197-W; available through our affiliation with amazon.com; Photo 1), or remove the old 12.5-cu.-in. box and replace it with a flush-mount 20-cu.-in. box that’s 7/8 in. deeper (Photo 2).

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Required Tools for this Project

Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.

  • Cordless drill
  • 4-in-1 screwdriver
  • Electrical tape
  • Hacksaw
  • Drywall saw

Required Materials for this Project

Avoid last-minute shopping trips by having all your materials ready ahead of time. Here's a list.

  • Extender box
  • Deep remodeling box