I have an 1,000 amp feeder that needs to go to a building 800 feet away. The feeder will need to be routed outdoors on the roof of several other buildings that are rated Class I Division 2. Due to voltage drop, I believe I'll need (4) sets of 600KCMIL. However, I don't know if I should use a cable tray or conduits. I want to use whatever makes the most sense and is the most economical. If I should use a cable tray, what types of cables should I use and what type of cable tray? Do they need to be suitable for a Class I Division 2 environment as well? I'm assuming the cable tray would need a cover since it's outdoors.