Dear Mr. Electrician: How do I extend my kitchen counter back splash electrical outlets from the wall a little? I am remodeling the entire kitchen and will be having a ceramic tile back splash installed. The outlets only need to extend out less than an inch.
Answer: The use of electrical box extenders or receptacle extenders are a simple and approved method for extending the depth of an existing electrical box. In order to use them the existing electrical outlet box must be in good condition and the screw holes must be able to tightly hold 6/32 machine screws. Otherwise the existing electrical box should be replaced. Note: Text links below go to applicable products on Ebay and Amazon.
Electrical receptacle or box extenders are required when adding depth to a wall as per article 314.20 in the National Electrical Code (NFPA 70). Electrical boxes are required to be flush with the finished surface to prevent any sparks from getting onto combustible wall materials and also to support the wiring device.
Extending Kitchen Counter Top Electrical Outlets
Often I find that the old original plastic electrical box is in need of replacing. In a kitchen I prefer to use adjustable boxes so I can adjust the electrical box to be at the perfect depth.
Below you can see the process that I went through to accommodate the new kitchen cabinet arrangement with electrical outlets.
Most of the existing outlets had no need to be relocated, the electrical boxes just needed extending. A new wall oven was going to be installed, so I moved the outlet from that location.
I had to make some changes to the ceiling light switch that someone had moved in a previous renovation. There was already a switch and light above the sink that I was able to use some of the existing wiring from for the new low voltage sink lights.
The first thing that I did was draw a couple of level lines at back splash height and cut out the drywall where I needed to work. The job called for installing new undercabinet lighting in addition to extending and relocating outlets. You can see part of the undercabinet lighting installation on my post here.
I like to use adjustable depth electrical boxes for kitchen and bathroom outlets and switches. That way I am prepared for any thickness of finished wall or back splash. After I install the adjustable boxes during the rough-in wiring phase of construction, I adjust them so that they are sticking out further than they need to be. That ensures that whoever installs the wall coverings will fully cut around the electrical box. If I kept the box recessed, I would wind up cutting the hole bigger to accommodate the wiring device. I have no problem cutting drywall, but tile and stone are more difficult to work with.
I like to use the deeper receptacle extenders for the rough-in phase. That way whoever installs the back splash will have to cut around my box. After the back splash is finished I changed the extenders to the proper depth. Too often it has happened where I get called in after the back splash is installed and have to make the holes in the wall bigger. I had to buy a RotoZip tool and diamond bit so I can trim the tile and stone on kitchen counter back splashes.
The Receptacle Extenders do a good job of supporting the electrical outlet or switch so that the devices are even with the finished wall. After the wall is finished you could also use box extenders instead to fill in the gap and support the wiring device.
I added the two 3/4″ Receptacle Extenders to the above switch and outlet during the rough-in phase so that any installer that mounts something over them will have to cut around the extenders, making my job easier when I have to install the new outlets, switches, and wall plates.
By attaching the 3/4″ Receptacle Extender to the existing outlet electrical box during the rough-in, I was given a very cleanly cut hole in the tile back splash to install the GFCI outlet during the finish phase of construction. I simply removed the 3/4″ extender and installed one that is the proper depth like the blue one above which is 1/2″ deep and adds 3.3 cubic inches to the overall box fill.
According to the National Electrical Code a certain amount of cubic inches is required for each wire in an electrical box. See article 314.16 for more information about box fill.
When installing wiring where kitchen cabinets are going to be installed it is a good idea to use steel protective nail plates. Cabinet installers tend to use very long screws to attach their cabinets to the wall.
You can see in the above photo the nice cutting around the electrical box that was done by the tile installer. If that black extender was not there, the opening to the electrical box would have been cut smaller.
The four sizes of receptacle extenders pictured above are 1/4″, 3/8″, 1/2″, and 3/4″. Notice the notch on the upper right corner of the 3/4″ receptacle extender. I had to cut it a little to accommodate a receptacle.
The above Arlington #BE1 Box Extenders work very well and are approved for use with electrical boxes. These are inserted into the existing electrical box in the wall after the wall has been finished and is ready for switches, receptacles, and wall plates to be installed. They can easily be trimmed back if too deep for your application.
I put Receptacle Extenders on all of the existing outlets and switches during rough-in so the person who installs the back splash tile will have to cut around them.
There was an old BX cable feeding the old peninsula outlet. I replaced it with MC cable and ran it through the inside of the cabinet to the side mounted outlet box using an MC cable connector after inserting an anti-short bushing inside the cable.
The finished GFCI Claro outlet and wall plate on the peninsula is a designer color from Lutron.
More work on this kitchen can be seen on this post.
My other kitchen posts are listed here.
What type of back splash are you planning for your kitchen counter top?