30 amp duplex

[480sparky]

So when you use a 20A CB with 15A receptacles this is legal correct? then you could potentially have 20A flowing thru a 15A device if the receptacles are line / load wired then the first receptacle would see the sum of the rest correct???

The current-carrying parts of a 15a receptacle are the same as a 20a receptacle. The only difference is whether it will accept a 20a plug.