Kitchen Counter Electrical Outlet Extension

Extending Existing Electrical Outlets on a Finished Wall

The bare Kitchen walls after all old cabinets, counter top, and appliances have been removed
The bare Kitchen walls after all old cabinets, counter top, and appliances have been removed

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.

10% OFF Coupon (Select Items) SUMMER10 Smarthome

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.

The finished kitchen after new cabinets, under cabinet lighting, counter top, tile back splash, electrical outlets, and appliances are installed
The finished kitchen after new cabinets, under cabinet lighting, counter top, tile back splash, electrical outlets, and appliances. are installed.

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 wallboard has an opening approximately 12" wide at counter top height, going around the room. This is to facilitate the installation of wiring for new under cabinet lighting
The wallboard has an opening approximately 12″ wide at counter top height, going around the room.  This is to facilitate the installation of wiring for new under cabinet lighting.

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.

Close shot of a metal adjustable outlet box, mounted on a wood wall stud, with 12/2 Romex wiring entering from the bottom. The ground wire is under a screw in the back of the box.
Close shot of a metal adjustable outlet box, mounted on a wood wall stud, with 12/2 Romex wiring entering from the bottom.  The ground wire is tight under a screw in the back of the box.

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.

Ebay Sells Adjustable Electrical Boxes

A one gang adjustable electrical outlet box, Steel City #MB120ADJ protruding from the unfinished drywall
A one gang adjustable electrical outlet box, Steel City #MB120ADJ protruding from the unfinished drywall.
Existing kitchen outlet box with a 3/4" receptacle extender to push the outlet to the new wall depth
Existing kitchen outlet box with a 3/4″ receptacle extender to push the outlet to the new wall depth.

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.

GFCI outlet mounted to the ceramic tile back splash using a receptacle extender for support
The GFCI outlet mounted to the ceramic tile back splash using a receptacle extender for support.

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.

Two existing counter top electrical boxes that I added receptacle extenders on to
Two existing counter top electrical boxes that I added receptacle extenders on to.

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.

Old counter top electrical receptacle in new ceramic tile back splash with blue receptacle extender
Old counter top electrical receptacle in new ceramic tile back splash with blue receptacle extender.

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.

Electrical outlet box in ceramic tile back splash with a blue extender attached and wires hanging out
Electrical outlet box in ceramic tile back splash with a 1/2″ blue receptacle extender attached and wires hanging out.
Finished GFCI electrical receptacle mounted on the kitchen ceramic tile back splash
Finished GFCI electrical receptacle mounted on the kitchen ceramic tile back splash.
Some Romex cables passing through a wood wall stud that has a steel protector plate fastened to its surface.
Some Romex cables passing through a wood wall stud that has a steel protector plate fastened to its surface.

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.

Old switch hanging from the switch box with a black receptacle extender attached
Old switch hanging from the switch box with a black receptacle extender attached.

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.

Dimmer switch and blue receptacle extender about to be mounted to the ceramic tile kitchen back splash
Dimmer switch and blue receptacle extender about to be mounted to the ceramic tile kitchen back splash.
Four different depth electrical box receptacle extenders
Four different depths of electrical box receptacle extenders.

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.

Three Arlington Industries electrical box extenders
Three Arlington Industries electrical box extenders.

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.

New peninsula kitchen counter with hole cut for an electrical receptacle outlet
New peninsula kitchen counter with hole cut for an electrical receptacle outlet.

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.

The 3.5" deep metal one gang electrical box mounted in the peninsula counter side all ready for an electrical outlet to be installed. The box was fastened to the wood using #6 brass wood screws. The green ground wire is tightly secured to the back of the metal box.
The 3.5″ deep metal one gang electrical box mounted in the peninsula counter side all ready for an electrical outlet to be installed. The box was fastened to the wood using #6 brass wood screws. The green ground wire is tightly secured to the back of the metal box.

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 kitchen peninsula electrical outlet on the end of the cabinet
The finished kitchen peninsula electrical outlet on the end of the cabinet.

The finished GFCI Claro outlet and wall plate on the peninsula is a designer color from Lutron.

Finished kitchen cabinets with, counter top, back splash, under cabinet lighting, and electrical outlets ready to use
The finished kitchen cabinets with counter top, back splash, under cabinet lighting, and electrical outlets ready to use.

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?