Hi all, My Daughter just bought a house that was a mobile home, double wide, that was
put on a foundation. Outside there is a service entrance panel with a 200A main breaker.
That feeds into the basement to an empty box where it is bolted to an SE cable that runs
the width of the house to the rear and up into the kitchen. There she has a 200A main panel
with all the branch circuits.

I want to finish the basement for her. Assuming there is plenty of juice (there are 7 spares
in the panel upstairs), here is what I would like to do if it is legal, safe and compliant with
NEC (in Maryland),

Shut off the Main 200A outside
Undo the bolted "feed thru" in the basement
Rebolt it along with another set of 4ga/4 wires and put another panel there
to feed the basement.

I know I could just use a subpanel in the basement and feed it from the kitchen, but
if TWO main panels in parallel is legal, it would save me a lot of wire ($$).
If I can do this, I would use a panel with say a 70A main breaker in it in the basement
and not just a subpanel with main lugs.

Your thoughts? Thanks.