It is commonplace for homes today to have one or more of three different laundry circuits. Each has its own unique assignment for supplying power to the laundry appliances. One is a 20-amp circuit designated to run the 120-volt power for the washing machine and the control power for the dryer. This circuit can also supply general-use devices. It is wired with 12-gauge wire and is usually type THHN or THWN wire. This is a dedicated circuit for the laundry room only.
The second is a 240-volt outlet that supplies a 30-amp circuit to feed an electric dryer. This circuit is wired with 10-gauge wire and is also THHN or THWN type wire. This feed is exclusively for and electric dryer and nothing else.
The third is one you may not have thought of. What would a laundry room be without a circuit for lighting? The lighting circuit may not be an independant circuit, and in fact, usually isn't. It is likely it will be on the same circuit as an adjacent room or hallway.
With the following electrical wirng tips, you'll be able to add an outlet, install a dryer outlet, or install a single-pole switch in no time.