The Electrical Code

210.22 Permissible Loads, Individual Branch Circuits. This happens all the time and basically it probably why you asked google the question as to how to add more receptacle. And all its saying that what ever you are plugging in and what is already plugged in should not go over the breakers amp rating. So in a perfect world yes this can happen but we don’t live in this type of world. And uncle Dave the electrian that loves you and you love him tried to give you what you needed but now it’s becoming a pain in the you know where to give the upgrade you need and all he does is add a new receptacle to an existing circuit. Well this article just tries to stop the breaker from tripping every time you turn on the vacuum.

“An individual branch circuit shall be permitted to supply any load for which it is rated, but in no case shall the load exceed the branch-circuit ampere rating.”