An old work (retrofit) electrical box is a game-changer when it comes to adding outlets, light switches, or other devices to an existing wall or ceiling. Unlike new construction, where electrical boxes are installed before the drywall, retrofit boxes are designed to be installed after the drywall is already in place, saving you the headache of tearing down walls. These boxes play a crucial role in safely enclosing wire connections, minimizing the risk of electrical hazards such as short circuits and fires.
Getting Started:
Installing an old work electrical box is a straightforward task that requires minimal tools, making it accessible even for those with basic electrical repair skills. While running cable through walls may be time-consuming, installing the box itself is typically a quick process.
Choosing the Right Box:
Old work electrical boxes come in various sizes and materials, including metallic (steel) and nonmetallic (PVC, phenolic resin, or fiberglass) versions. Metallic boxes require grounding, whereas nonmetallic boxes do not. Selecting the appropriate box depends on the specific requirements of your project and the type of cable you’ll be using.
Understanding the Anatomy:
Before diving into the installation process, it’s essential to grasp how old work boxes function. Unlike traditional electrical boxes, which are secured directly to studs during new construction, old work boxes utilize a unique fastening system. This system relies on retention tabs and mounting ears to anchor the box securely in place against the drywall or plaster, ensuring a snug fit without the need for stud attachment.
Safety First:
Before proceeding with any electrical work, safety should always be the top priority. If you’ll be working with live electrical wires, it’s imperative to turn off the circuit breaker controlling the circuit to prevent accidents. If unsure, it’s safer to shut off the main breaker to cut power to the entire house.
What You’ll Need:
- Equipment / Tools
- Flat-blade and Phillips-head screwdrivers
- Pencil
- Keyhole saw
- Wire-stripper
- Torpedo level
- Utility knife
- Materials
- Old work nonmetallic electrical box
- Wire connectors
Step-by-Step Instructions:
- Prepare the Retention Tab Screw:
- Before installation, tighten the retention tab screw slightly to pre-cut the threads, making it easier to secure the box later without damaging the wall.
- Prepare the Box’s Cable Clamp (PVC Boxes Only):
- For PVC boxes, pry open the clamping tab to facilitate the insertion of the electrical cable, ensuring a smooth installation process.
- Prepare the Electrical Box Opening in the Wall:
- Trace the outline of the box on the wall and use a utility knife to score along the outline. Carefully cut the hole using a keyhole saw, ensuring the dimensions match the box size.
- Run Cable and Strip the Sheathing:
- Run the electrical cable through the wall opening, leaving excess cable for flexibility. Use a wire stripper to remove the outer vinyl sheathing, exposing the conductors and ground wire.
- Insert the Cable Into the Box:
- Thread the stripped cable into the old work box, ensuring the sheathing is securely clamped under the clamp or clamping bar.
- Insert the Old Work Box Into the Wall:
- Position the box in the wall opening, ensuring the mounting ears are tight against the front of the drywall. Tighten the retention screws to secure the box in place against the wall.
- Strip Wire Insulation From the Conductors:
- Using a wire stripper, strip insulation from the ends of the wire conductors, exposing the metal conductors for connection.
- Attach Wire Nuts:
- Screw wire nuts onto the ends of the wires to protect the exposed conductors until final connections are made.
By following these steps, you can confidently install an old work electrical box, adding functionality to your space without the need for extensive renovations. Just remember to prioritize safety and attention to detail throughout the process for a successful outcome.
