Looks Like my 200 amp Main is Full ... adding a Sub Panel ...

[Stuart in MN]

To understand what you are saying, as long as you have multiple 15 amp duplex receptacles on a circuit, you can use a 20 amp breaker?

You can have multiple 15 amp receptacles on a 20 amp circuit, and a regular duplex receptacle counts as two, so you can have one or more duplex receptacles on a 20 amp circuit. 15 amp duplex receptacles are designed for 20 amp feedthrough, which means the insides of the receptacle can handle 20 amps passing through them on to the rest of the circuit. The only real difference between a 15 amp and a 20 amp duplex receptacle is the shape of the openings on the front, a 20 amp receptacle has an extra sideways slot like this:

 

[jake26]

Thanks Stuart. That is what I thought and just finished wiring my garage with that thought in mind. The way the post was worded confused me a bit but that is easy to do.

 

[mrb]

To understand what you are saying, as long as you have multiple 15 amp duplex receptacles on a circuit, you can use a 20 amp breaker?

one 15a duplex is ok too. you cant put one 15a single receptacle on a 20a circuit. the wiring has to be 12ga of course.

 

[Stuart in MN]

It can be a little confusing, since duplex receptacles are almost universal - you don't often see singles.