- 1-in. spade bit
- Cordless drill
- Jab saw
- Wire stripper/cutter
Kitchens need to be on a dedicated 20-amp circuit and require 12-gauge wire. Today, 12-gauge wire is wrapped in a yellow sheath, but your old cable may be white. New circuits in kitchens need both arc fault and ground fault circuit interruption (AFCI, GFCI) protection. In this story, we’re adding an outlet to a kitchen that already has GFCI protection, which has been required for many years. If your kitchen is not on a 20-amp circuit, or doesn’t have GFCI protection, you’ll have to install a new circuit or circuit breaker. For more information, check out Breaker Box Safety: How to Connect a New Circuit. Also, discuss your project with your local electrical inspector when you apply for a permit. If adding a circuit still seems above your pay grade, then call an electrician.
The first step is to shut off the power. If your breaker panel is poorly labeled, plug a radio into the outlet you plan to pull power from, and start shutting down breakers until the music stops. There may also be wires from other circuits in the junction box, so probe the box with a noncontact voltage tester (try the Klein-NCVT-1) before you disconnect any wires. Cover the ends of the existing wires with wire nuts as an additional precaution.
Caution: If you discover aluminum wiring, call in a licensed electrician who is certified to work with it. This wiring is dull gray, not the dull orange that is characteristic of copper wire.
Project step-by-step (13)
Remove the existing box
It’s easier to fish the new cable if you remove the existing box in the wall. Fiberglass boxes can be busted out with a hammer and a chisel or sturdy screwdriver. It’s best to cut the nails on plastic boxes with a hacksaw. Start by probing with a screwdriver to find which side of the box the stud is on. Then pry the screwdriver between the stud and the box to make room for the saw blade.
Note: Metal boxes are difficult to remove without creating some drywall repairs. Before you attempt it, see if you can fish the cable down through the existing metal box into the hole in the cabinet.
Cut a hole for the new box
There’s no rule mandating the height of the new box, so just match the height of the existing one. The code for kitchens states that there must be an outlet within a 2-ft. reach from anywhere along the countertop, excluding those areas where there’s a sink or stovetop. This means there should be an outlet every 4 ft. If you’re just adding one outlet, you probably won’t be subject to this rule, but if you’re remodeling the entire kitchen, you probably will. It’s best to check with your local electrical inspector.
Before cutting the hole, go to the floor below and, if possible, check to see if there are any pipes or ducts running through the wall you plan to cut into. Or go outside and see if any vents are sticking through the roof in that area. If you’re not sure, make a small exploratory hole that can be easily patched.
The new box does not have to be right up against a stud. In fact, it’s easier to install if it’s not. Trace around the new box, and cut the hole with a jab saw. Don’t shove the saw all the way into the wall cavity, just in case there’s a wire or pipe hidden behind the wall.
If your backsplash is tiled, use a rotary tool fitted with a diamond tile-cutting bit. Set the depth of the bit so it cuts through the tile only. Finish the cut with a jab saw. Whenever possible, use the grout lines for two sides of the hole because cutting will be much easier. Drill starter holes in two opposite corners with a glass-and-tile drill bit.
Drill the holes for the cable
Empty the cabinets, and pull out the drawers to get better access. Lying on your back halfway inside a cabinet is not the most comfortable position, so throw down a couple of couch cushions before you get started. And be sure to wear eye protection. Drill a 1-in. hole for the new cable in the cabinet-near the top. Don’t let the bit travel too far into the wall cavity, or the insulation may twist up like cotton candy on a stick and make it difficult to pull the bit back out. Drill through the sides of the cabinet near the back for the conduit to pass through.
Fish in the new cable
Measure the distance the new cable will travel both horizontally and vertically, and then add several feet before cutting it-it’s better to throw out a few feet of cable than end up short. Shove one end of the cable through the hole up toward the box hole. It doesn’t matter if you start at the new or the existing outlet side. Our expert puts a slight bend on the end of the cable so it hugs the back of the drywall. This will help keep it from getting hung up on insulation.
Prep the conduit
Measure the length of the flexible conduit by sliding a tape measure through the holes in the side of the cabinet. Have a buddy hold the end of the tape in the hole or secure it with masking tape. Cut the conduit to length and attach a bushing or fitting to the side you plan to push the wire through. Bushings and fittings protect the cable from getting damaged on the sharp edges of the conduit. Our expert likes the 90-degree fitting because it results in a nice ‘finished’ look with no cable exposed. A standard bushing will result in a small section of exposed cable at the ends, but that’s acceptable.
Slide the conduit into place
Push the cable through the conduit so it sticks out a few inches on the other side, and then slide the conduit through the 1-in. holes in the side of the cabinets. Once the conduit is through, install the bushing/fitting on the other end of the conduit, and pull the cable the rest of the way through the conduit.
Secure the conduit
Push the cable up through the second hole in the wall the same way you did the first, and then secure both sides of the conduit with straps near the hole. If the conduit travels more than halfway across the length of the cabinet, add another strap halfway between the end of the conduit and the hole in the cabinet.
Install the new boxes
It’s easier to remove the cable sheathing before installing the new ‘old work’ boxes, but make sure to leave enough on the cable so about an inch of sheathing pokes into the box. Once the sheathing is removed, pull the wires into the box, slide it into place and secure it.
There are several kinds of ‘old work’ boxes, sometimes called ‘remodel boxes.’ ‘Old work’ boxes don’t get nailed to a stud but instead are secured with wings that clamp onto the drywall as a screw is turned. The type shown here is made from sturdy fiberglass and is available at most home centers.
In this wiring scenario, five individual 12-gauge wires are occupying the source box (all grounds count as one), so the 18-cu.-in. box shown here is large enough to handle all the wires and receptacle without crowding. You may need a larger box if there are six or more wires.
Figure A: Diagram of new cable and conduit
Install a tamper-resistant AFCI receptacle at the source outlet as shown in Figure A. The outlets downstream can be standard tamper-resistant receptacles.
Wire the new receptacles
All outlets in a kitchen require AFCI and GFCI protection. In this example, we’re working with a kitchen circuit that already has GFCI protection at some point upstream, which means that we only need to install a receptacle that has AFCI protection. One properly wired AFCI outlet will protect all the other 20-amp outlets downstream. Virtually all newly installed receptacles need to be tamper resistant, so look for the ‘TR’ before you buy.
Figure B: Wiring diagram for AFCI receptacle
All the line (incoming) and load (outgoing) wires need to be in their proper places (Figure B). If you’ve wired receptacles before, you may have used ‘pigtails’ to connect them. That’s where the hot, neutral and ground wires run continuously with small pigtail wires pulled off and connected to each receptacle. Using pigtails is a great way to ensure that if one receptacle goes bad, the rest downstream stay operational. But when wiring GFCI and AFCI receptacles, only the ground wires can be hooked up with pigtails; otherwise the outlets downstream will not be protected.
Planning to tile?
If you plan to tile your backsplash, adding outlets is even easier than we show here. Just run the new cable through a channel in the drywall. A channel is easier because you don’t have to empty out the cabinets or mess around with conduit, and the wall can be quickly patched. Make the channel with a jab saw. Cut it a bit higher than the boxes so there’s room to bend the cable down into the hole. Install a steel nail plate to protect the cable from future nails or screws.
A ground fault occurs when electricity travels outside its intended path (wires), and seeks the shortest route to the ground (you). Water is often the cause of a ground fault. That’s why, for many years, kitchens, baths and outdoor outlets required GFCI protection, which shuts down the power before injuries occur. An arc fault occurs when electricity jumps from its proper conductor to an unintentional conductor. Common causes are pinched wires, frayed or cracked wire insulation, and wires damaged by screws, nails or staples.
An arc fault can cause a fire, which is why AFCI protection has recently been mandated by the new electrical code for most of the house. Until recently, the only way to achieve both GFCI and AFCI protection on the same circuit would be to install one form of protection in the panel and the other in the first available receptacle. Now there are dual-function breakers available that offer both types of protection. The 20-amp breaker shown here costs $50 at home centers. Look for dual-function outlets in the near future.
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