Tag: old work metal outlet box

Dear Mr. Electrician: How do I go about installing an electrical receptacle box using Madison Bars?  I want to install an electrical outlet on a dedicated circuit for my window air conditioner, and someone told me to use electrical Madison Bars to mount the outlet box. Answer: Installing an electrical receptacle box using Madison Bars is a simple method for mounting particular metal electrical switch and outlet boxes in a wall. Electrical Madison Bars are also known as Old Work Box Mounts, Old Work Support Clips, F Clips, F Straps, Madison Clamps, Jiffy Clips, Hold-It Box Supports, Madison Clips, and Madison Straps.  In some parts of the country, they are called Battleships. The electrical manufacturer Hubbell Raco calls them GRIP-LOK Old Work Switch Box Supports with 1 7/8" long legs.  The catalog number is 8977. The manufacturer Steel City named them Old-Work Switch Box Steel-Mounting Holder #820D. NOTE: Some text links below go to applicable products on Amazon or eBay.  As an Amazon Associate, I earn from qualifying purchases. The photo above shows Madison Bars, which are two different lengths.  The longer ones work on walls with double drywall or a finished surface such as tile or paneling. In addition, switch box support clips are shown in the photo that can also be used to attach metal outlet boxes to the wallboard.  They clip onto the front of the electrical switch box with a little force.  Once the box is in the wall, you tighten the screw, and the clips wedge themselves between the box and the inside of the wall.  You can also buy electrical switch boxes with built-in switch box support clips. In the example below, the hole was made using a Compass saw.  The metal outlet box was held against the wall, and a pencil line was traced onto the surface.  Note the notches on the upper right and lower left corners.  They are to allow for the protruding screws on each side that all gangable metal receptacle boxes of this type have. The boxes are gangable by removing one or both sides and screwing the boxes together with additional boxes to make a multi-gang switch or outlet box.  You can add as many gangs as needed; however, the more gangs, the more difficult it will be to find wall plates to cover the finished work. You can special order multiple-gang wall plates from an electrical supply company, but you may be limited in choosing colors and styles.  I have found it best to limit your gangs to four to find wall plates easily.  Over four gangs usually must be specially ordered. Decora-style switches, outlets, and combination devices have the same style outlet cover, making it much easier to find wall plates.  The same wall plates also fit over GFCI electrical receptacle outlets. For the hole above, I held the face of the electrical box against the wall and penciled an outline to follow with my Compass Saw. Top Of Page INSTALLING AN ELECTRICAL OUTLET BOX USING MADISON BARS The ground wire above is attached to the box using a separate...