ok, so after some digging in the insulation I've found that I've got plenty of wire and I don't have to rerun the entire thing back to the breakers, just lop off the burnt stuff (plus a foot) and move the box to a different (and infinitely better) location. just need to buy new longer wire to run back into the heat pump assembly. plus a new lockout assembly of course. my big fear is that the 50volts I was detecting at the blower motor (which lead me back to the lockout box) has hurt something else in the system. we shall see. one step at a time...