Homeowners with even a modest skill set in home improvement can add a touch of elegance to their home by installing a single button doorbell. Aside from the added charm, the pleasant sound of a doorbell will beat out a sharp knock every time. Although today's sophisticated doorbells offer sounds ranging from a simple "ding dong" to a custom tune, installation has not changed much over the years. Most hardwired doorbell systems utilize a transformer that converts your home's 120 volt AC current to a much lower voltage between 8 and 24 volts. This article will focus on the installation of a simple, single button doorbell equipped with a transformer, chime, and applicable wiring.
Step 1 - Locate a Power Source
It's common to place the doorbell's transformer in the attic and connect it to an existing power source such as a ceiling light box or an attic outlet. In short, the transformer must be connected to an existing 120 volt power supply in the attic such as a ceiling light box. Use the voltage meter to verify that the connecting circuit has continuous power and is not operated by a switch, which would render your doorbell inoperative when in the 'off" position.
Step 2 - Turn Off the Power
It's essential that you turn off the power to the applicable circuit that will power the transformer. Using the voltage meter, verify that the power to the electrical ceiling box or outlet is indeed off. Connect the wires from the transformer -- black, white, and green -- to the corresponding wires in the electrical box by twisting each one together and securing them with wire nuts.
Step 3 - Run the Two-stranded Wire
Most doorbell manufacturers include the necessary wire in a doorbell installation kit. There should be two lengths of wire included in the kit, one two-stranded and one three-stranded length.
The two-strand length of wire traverses between the doorbell button and the transformer. As such, you will need to run this wire from the location of the transformer in the attic and down the wall that will support the button. You may find it necessary to drill a couple of holes and use a fish tape to snake the wire down the wall to the button location.
Step 4 - Run the Three-stranded Wire
Run the three-stranded wire from the chime to the location of the transformer. You may find it necessary to drill additional holes and use the fish tape as mentioned above.
Step 5 - Mount the Bell or Chime
Position the chime in the desired location on the wall and plumb with a small level. Using a pencil, lightly mark the location of the mounting holes on the wall. Affix the chime to the wall using plastic anchors, toggle bolts, or similar wall anchors. Often, manufacturers include them with a doorbell kit. The type of wall surface -- drywall, masonry, or wood -- will dictate the type of anchor required.
Drill applicable sized holes in the wall at the mounting hole locations and use the applicable type screws to secure the chime to the wall. It is important to remember to make sure to fish the door chime wire installed earlier through the back of the chime before securing it to the wall.
Step 6 - Connect the Chime Wires
A doorbell system requires that it be wired correctly to function properly. It is important to note the manufacturer's wiring instructions should supersede those mentioned here. Most single button installation kits are manufactured with the option of adding a second button for another entrance in the future as a convenience. As such, the chime is supportive of two buttons, hence the three wires. Whether or not you are using a second button, it is a good idea to wire the chime accordingly. Three terminals on the chime are labeled F, T, and B, which represent the front door, back door, and transformer.
Remove the outer sheathing from the three-stranded wire and strip about a 1/2 inch from the ends of each wire using a pair of wire strippers. Loop the black wire around the T terminal, the red wire to F terminal, and the white wire to the B terminal and tighten the terminal screws using a screwdriver. Install the chime cover to complete installation of the door chime.
Step 7 - Connect the Door Bell
Remove the outer sheathing of the two-stranded doorbell wire to expose a red and white inner wire. Strip about 1/2-inch from the ends of each wire. Secure the white wire to the top terminal and the red wire to the bottom terminal located on the back of the doorbell button. It is a good idea to caulk around the wire where it extends from the jamb or wall with some silicone or latex caulking. Affix the doorbell to the jamb or wall using the applicable mounting screws.
Step 8 - Wire the Transformer
At the transformer, remove the outer sheathing from both the two-stranded wire connected to the doorbell and the three-stranded wire connected to the door chime. Strip about a 1/2 inch from the ends of each wire using the wire strippers. Connect the wires according to the following sequence:
Twist together the red wire from the chime to the red wire from the doorbell wire and secure them together using a wire nut.
Loop the black wire from the chime around one of the terminals on the transformer.
Loop the white wire from the doorbell button around the remaining terminal on the transformer.
Cap the remaining white wire from the chime with a wire nut.
Tighten the terminal screws on the transformer, restore power to the circuit feeding the transformer, and test the doorbell.