Installing a 200amp all in one box outside , not much will be on this one, just a few circuits - 30 ft away I need a 125 amp sub panel 22 breakers 15 & 20 amp & 6 240v lines that are ALU old gray type wire & will have 30,40,amp breakers. Will power a 2 ton & a 3 ton air unit.
What wire size should I run 1/0 or #2 wire to the sub ??
2 hot -1 neutral, & what size for the ground ?
please explain about keeping the neutrals and ground buss separated, only in the sub panel?
Permits are in hand.