Large living rooms and family rooms face some unique challenges when it comes to wiring. The great rooms that are so popular in "open concept" designs create large expanses of space that are quite some distance from the walls where the electrical outlets are normally installed. What do you do if your room includes a sitting area in the middle of the room? You would like a lamp or two, but you are 10 to 12 feet or more from any wall outlet. Long extension cords running along the floor can be an obvious tripping hazard.
The answer is a floor outlet. Often known in the electrical trades as a poke-thru or drop-in, a floor outlet has a specially designed mounting plate that fits virtually flush with the floor surface. The outlet receptacle itself is sometimes flush with the floor level, as well; or it can be recessed down below the surface of the floor, with a secondary cover plate that covers the receptacle opening when it is not in use.
A variety of commercial products are available to simplify poke-through floor outlet installation, including the Thomas & Betts model E971FBDI shown here. This product is especially convenient because it comes with everything you need for a complete in-floor installation, including a special tube-shaped floor box, the outlet receptacle, the wire nut connectors, and even the hole saw required to drill the hole in the floor. Not only can you use it for an electrical outlet, but it has adapters that let you use the box to run communications lines, such as a phone line or computer network cable.
Any number of other floor box products are also available, some with single receptacles and others accommodating duplex receptacles. Most have flip covers or screw-in covers for protecting the receptacles when they are not in use. Some kits include just the surface cover plate, requiring you to buy a standard electrical box and receptacle separately, while other kits include virtually all the parts necessary.
Equipment / Tools
- 1 Hole saw (or a jigsaw or reciprocating saw, depending on the shape of floor box)
- 1 Drill
- 1 Wire stripper
- 1 Screwdriver
Many of the parts will be included in a kit. Check to see if the part is included before purchasing separately.
- 1 Thomas & Betts Drop-In Floor Outlet (Model E971FBDIs)
- 1 Floor electrical box
- NM two-wire cable
- Single-receptacle or duplex receptacle
- Wire nut connectors
As with any electrical installation, a good understanding of electrical work is required if you are doing this work yourself. As an alternative, you can install the floor box, then leave the electrical connections to the circuit to a licensed electrician. Here is an overview of the process:
Cut Through Carpeting and Padding, if Necessary
If you have carpeting, cut an opening in the carpeting and padding to access the wood subfloor. The Thomas & Betts kit used here requires a 2 3/8-inch hole cut with a hole saw.
Cut the Hole in the Floor
Use a power drill to drill a hole in the flooring and subfloor. Use a hole saw sized according to the instructions that come with the kit. Some kits include the necessary hole saw. Some floor boxes may require a rectangular floor opening; if so, use a reciprocating saw or jigsaw to cut this opening.
Run Wiring to the Floor Box
Run wiring for a new circuit or circuit extension from the source (circuit breaker panel or an existing outlet on the circuit) to the floor box location.
Make sure that the cable size is appropriate for the amperage of the circuit: 14-gauge for a 15-amp circuit and 12-gauge for a 20-amp circuit.
Pull the NM Cable
Pull the two-wire (plus ground) NM cable up through the floor opening.
Prepare the Connections
Feed the end of the cable into the bottom of the floor box or tube. Strip about 3/4 inch of insulation from each of the wire conductors (white and black wires).
Connect the Cable
Connect the NM cable conductors to the receptacle—white wire to neutral (silver-colored screw terminal), black wire to hot (brass- or copper-colored) screw terminal), and the bare copper ground wire to the green grounding screw on the receptacle.
Set the Box in Place
Tighten the wire clamp holding the cable in the box. (With the Thomas & Betts model, this involves simply closing the bottom of the tube.) Insert box down through the hole in the floor.
Secure the Cover Plate
Fasten the cover plate to the floor, using the provided mounting screws.
Connect the Cable
Connect the new NM cable to the circuit breaker panel or to the source outlet being used to feed the new extension.
This is work that requires the circuit breaker panel to be shut off, and it should be done by a professional. Do not attempt this yourself unless you are very familiar with electrical work and confident in your skills.
Power and Test
Turn the power to the circuit back on and test the new floor outlet for proper operation.
You now have a power source in the middle of your floor and have eliminated any potential trip hazards from long extension cords.