Sid,
Quote
they say (some people) if its back to back you can put your main in the panel....
they are right, this meets the requirement of 230.70(A)(1).

This can be as much as 5,6, or even 10' in some locations. I don't know of any where that would allow 50', however you might want to look at 230.6 if you must run this far.

Roger