I would like to replace some of the existing light switches in my home.

To simplify this explanation, my hallway has a light fixture at the top (2nd floor) and bottom (foyer) of the stairs. Two sets of switches controls each light fixture. Two are at the top of the stairs, and they control the top and bottom light. One exists alone at the bottom of the stairs, which controls the 2nd floor light. Another sits by the front door, and controls the bottom light (foyer).

I stopped myself from replacing the switches because when checking the wiring on one of the switches, I noticed two wires connected to one screw. I am sure this is normal, but before I update my switches, I would like to know what I am doing.

Could anyone provide information on this wiring arrangement. Also, do I need to use a specific switch to accommodate this wiring arrangement?

 

You need what are called three way switches. Three way switches allow a light to be controlled from two different locations.

These switches have three screw terminals on them (not counting the ground screw). One screw will be a slightly different color than the other two. All you need to do is to make sure that you connect the wires to the same terminals on the new switch.

As for two wires under one screw, this is not allowed. When you replace this switch you will need to use a wire nut and connect these two wires and a short piece of wire (called a pigtail) together. This pigtail is then connected to the screw terminal of the switch.

 

There are lots of reasons why two wires might connect to the same screw (with a pigtail). If you're just replacing the switches, it's not important to figure it out. Just follow Bob's directions and work methodically. And before you disconnect anything, make a detailed drawing of the existing connections. And don't throw away the old switches until it all works perfectly.

 

Thank you. I will most likely take of care this either this Saturday or Sunday. I'll post the result then.