I posted this on the electrical forum too, but know this one gets more traffic. We have a 400 amp service with a 200 amp panel in our garage/apartment. We then have a 200 amp disconnect at our service as well. We are building a house and are installing a 200 amp panel there. I mistakenly got a 200 amp main panel, thinking I could directly use it there (garage is 250' away from service and I liked the idea of having a main disconnect). Can I add a ground bus to this box and use it as a main lug or am I better off returning it and just getting a 200 amp main lug? Thanks!