I was helping a friend change his deep water well pump which is rated at 220 volts AC,3/4 H.P. Most of these I have seen are wired with three yellow wires that run from the pump to the pump switch on the water tank that are stranded. His was wired with three yellow stranded wires that were rated for the same voltage from the pump up to the top of the casing, where they installed the pump switch and used a coiled water tubing to connect to the pit-less adaptor to work the switch. From the switch they ran a 220 line underground, grey color, solid, three wire to the fuse box inside the house.
Which wire is better for this use? Solid or Stranded?