How can switches across the room from each other control the same light in my house? Are they in the same circuit? Is there a limit to the number of switches?
In: 10
A normal, two way, switch has two wires: the input, and the output. When the switch is on, they are connected, and when its off, they are disconnected.
You can also make a three way switch which has three wires: an input and two outputs. The switch swaps which output is connected to the input. With this, you can have two switches connected to the same device(s), with the double wire going between the switches and the “input” of one switch being the true output.
You can add more switches by making them four way switches. With these, you have two inputs and two outputs, and the switch swaps which input is connected to which output. Each of these four way switches is put in between the three way switches, and if you have an even number in differing positions, the circuit fully connects.
As a note, you can always make a four way switch into a three way switch by not connecting an input. You can also make a three way switching into a two way switch by not connecting an output. The more paths the switch has, the more complex and thus the more expensive it is.
TLDR: All of the switches will be on the same circuit, and on the same side of the device. There is no limit* to the number of switches you can have controlling the same device(s), however it just adds more cost, and there is rarely a benefit in having more than two switches controlling a device.
You can also use smart switches, and have them talk to each other outside the electric flow as an alternative solution. This is more expensive, newer, and adds more points of failure, however – its only really useful if you cannot add the extra wires or want to be able to control it remotely anyways.
* Well, eventually the resistance in all the wiring will be too high and no power will flow, but that number is so insanely high as to be irrelevant.
Latest Answers