I just installed a 30 amp (PS-13-HR) and a 50 amp (PS-54-HR) trailer power box from this outfit over the weekend at two different structures. I found a one inch conduit conversion for the top of the box at Home Depot and used a one inch offset to connect to the existing power panels. One inch is adequate for the four #6 wires for the 50 amp wiring.
WBCCI Life Member 5123, AIR 70341, 4CU, WD9EMC
TV - 2012 Dodge 2500 4x4 Cummins HO, automatic, Centramatics, Kelderman level ride airbag suspension, bed shell