I have 200 amp service poll with a 200 amp breaker box mounted on the poll, there are 3 wires from the meter to the box. One ground and 2 120 amp. No neutral wire. The poll has a ground wire in the ground beside it that the ground wire in the box is connect4ed to. I want run a line from bottom of box to a mobile home. There is 200 amp service box in the mobile home. Where they disconnected the service ( the home was moved) there are 4 wires in the box , 2 black, one green, one black with stripe. Can I use triplex (aluminum) wire to connect from pole to inside box or do I have to get quadraplex because that is what was there before. (if so where does the 4th wire run in the outside poll box) Also was going to run in conduit from pole to underside of mobile home (25 ft) then just let wire sit on ground under mobile home (49 ft) , then run in conduit up to box in mobile home( 6 ft). Is this okay or does the entire wire have to be buried? Does is have to be buried the whole way. (wire says direct burial) OR Should I mount the conduit to the underside of the mobile home and run the wire in it instead of laying it on the ground. The area is not zoned so there isn't any specifics to what can be done. I just want to be safe with what I do.

You absolutely DO need quadplex to feed the trailer.
You can go underground to the trailer and then lay the conduit on the slab under the trailer.

This statement is often made but so wrong:



The area is not zoned so there isn't any specifics to what can be done.

Every state in the USA has a State Electrical Code legislated by the State Congress. If any area of any state does not have any local code enforcement, the State will have Codes in effect that will cover that area.