Two way switches have a com terminal as well as l1 and l2 terminals. Attach to the bonded ground wires in the switch box.

Guide To Wiring Switches Amp Sockets Knowledge Base Jim
1 gang 2 way dimmer switch wiring diagram. If two switches control a single light or a group of lights you will. Wiring a standard 3 way dimmer switch. When l1 is on l2 would be off. Wiring two switches in one box with 2 sources. Two way switching means you can switch the same light fixture from two switches that are located in different sides of a room. With a three way dimmer you can control a light with two switches.
Three wire cable is supplying the source for the switches and the black and red wires are each connected to one switch. This lets you dim from one location and turn the lights on and off from another. These wires attach to the travelers which are the pair of wires attached to the two screws at one end of the regular 3 way switch. But if youre replacing a three way switch with a three way dimmer label the common wire itll be labeled on the old switch when you remove the old switch so you can connect it to the common terminal on the dimmer. Connect the line brown wire to the l terminal together with the supply cable line wire and connect the blue wire with the brown slewing to the swl terminal together with the lamps line wire. You will need a three way dimmer and a three way switch.
However if you need two switches to control a single lighting circuit such as in the case of at the head and foot of stairs so you can switch the lights on and off in both places you need to understand a 2 way switch. A 1 gang switch will control a single lighting circuit and with a 2 gang switch you can control two lighting circuits and so on. When l1 is off l2 would be on. It doesnt matter if you reverse the two switch wires to a single pole dimmer. Plus learn how to change a single. Learn how to wire a two way switch with expert electrical diy advice from videojug and aspect maintenance and complete your electrical wiring home improvements with ease.
If only one switch controls the light purchase a single pole dimmer. In position 1 when the switch is down or on com and l1 are connected together just like the one way switch. 2 gang 1 way light switch you dont see these as much now days as many manufactures only make 2 gang 2 way light switches that serve the same purpose you just dont use the third l2 terminal on each gang however i thought we would include it just in case you come across one. 3 way dimmer switches typically come with the following pre wired leads. Wiring a two way switch. This diagram shows two switches in the same box with a separate 120 volt source feeding each.
There are two wiring options for this.