Main breaker - subpanel - downsizing breaker ??

[krivalsi]

I am replacing an older subpanel in my basement.
I want 20/40 circuit spaces (Will currently only fill ~10 spaces).
I expect to be drawing less than 40A worst case (No kitchen or dryer).
The main feed is planned to be #6 NM (rated for 55A @ 60C).

I am planning on buying a 100A panel with 20/40 spaces.
I would like to swap out the 100A main breaker with a 50A main breaker!

Question #1: Do they make main breakers at the 50A level?
Question #2: Will they mechanically fit into main breaker spot?
Question #3: Does any of this sound like a bad idea?

thanks, Ken

 

[tom baker]

As your occupation listed as retired does not indicate how you are related to the electrical industry, we are not able to approve your post, being of a DIY nature.