when to use a 15amp or 20 amp circuit

[vdotmatrix]

i have been involved in many projects around the house. the latest is i want to upgrade the wiring to the washing machine and give it it's own 20 amp circuit with a gfci(12/2). i wanted to put a regular 15 amp circuit quad outlet GFCI above the basement sink which is a few feet away. right now this same circuit starts in the garageat an outlet/light with a switch, goes through the wall to the washer outlet which i have a power strip and then it continues to the panel.

my question: can i run 12/2 on a 15amp circuit or is 12/2 only for handling a higher capacity circuit and only use 14/2?

[mrcaptainbob]

You won't be wrong using 12/2 with a ground.