Can You Have Two Dimmers on a Three-Way Switch?

A 3-way dimmer is very similar to a 3-way toggle switch.

Three-way switches are a common feature in household electric devices. Allowing for multiple switches to control the same light fixture can be useful for many situations, such as multiple story stairwell lights or the light in a long hallway.

Three-Way Switches

All household electrical functions operate on the principle of closed versus open circuits. Standard light switches only have two positions, open or closed, to either complete or break a simple circuit. Three-way switches are used in conjunction with three wire cabling to provide two separate routes for circuit completion.

Dimmer Switches

A dimmer switch has always been similar in function to a toggle switch, in that it completes a circuit. The variance between the two is that dimmer switches allow the user to alter the amount of electricity that reaches a light bulb. Many dimmer switches accomplish this by dampening the amount of voltage that flows through the circuit, while some modern switches actually open and close the circuit a variable number of times per second.

Dual Switches

Since dimmer switches and toggle switches perform essentially the same function, that is opening and closing a circuit, there is no reason why one cannot substitute the other. Additionally, using modern dimmer switches is an excellent way to prolong the life of a light bulb and thereby reduce replacement costs and electricity use.

References

• Ask the Builder: Dimmer Switch
• Ask-the-Electrician.com: Easy to Understand 3 Way Dimmer Switch Wiring
• Rick Matthews, WFU: Tutorial -- 3-Way Switches and 4-Way Switches