I'm doing an install to a mixed use office/house as follows. 240volt 3 wire single phase service, 400MCM copper service drop into dual meter pan. Each meters load side is 4/0 awg aluminum SE wire into two seperate 200 amp load centers in the basement. I know that I should be using 1/0 awg copper for the GEC based on tbl 250.66(400MCM), and I know that I should be using #4 solid for the grounded conductor bonding in each load center to the GEC. My question is where should I make that connection. I have had trouble in the past with making connections in the meter pan because it will be inaccessable after the electric utility locks the enclosure. My only thought on this subject is that perhaps the utility will only lock the meter enclosure sections of the dual meter pan. If that is the case, then the center, supply side connection in the meter pan will always be accessable and my problem is solved. The supply side of the meter pan is the only location where the grounded 400 mcm conductor is available. The final question is whether or not I can use a single 4awg run from the 1st loadcenter into the 2nd loadcenter and then out to the point of attachment to the 1/0 GEC
