I have 320amp service to my home. When I installed my 200 amp breaker panel in the basement I put dual lugs in the service can for future connection for my pole barn. I am wanting to put another breaker panel in the basement. I have split off all my rooms in my existing 200amp and need the extra room for my new wiring for my patio and my future pole barn to and would like to put it on the opposite side of the basement which is about 70ft from my outside service. I was looking to put in a 150 amp breaker panel, but was wondering if 100 amp would be fine. I am going to run underground wire from my second panel to my barn and that will be about roughly 150ft.

1, What would be your suggestion? I would like to stick with connecting off the dual lug in the service can through the house to the second panel.

2. What amp panel would you perfer 150 or 100?

3. Size of entry wire and ground for both panels and would I ground the second panel like I have my first 200amp panel grounded?

4. wire size from my second panel to my barn?

Thank you,
Ron :D