I'm running new electric in a friends basement and so far uncovered a lot of bad wiring jobs, buried splice boxes, you name it. So now I noticed that the central A/C compressor is wired with 10 guage wire.I'm pretty sure its suppose to be 8 guage. And also the existing 10 guage wire is hooked up to a 40 A breaker, which of course is not right, its suppose to be a 30A breaker. So since everything is wide open now, I was wondering should I run new 8 guage wire to the A/C? The unit is a Lennox, I beleive a 3 ton unit, and the plate says "Min circuit ampacity 24.4 amps" and it also says " Max fuse or ckt bkr 40A". Even if the unit has been running fine all these years, I'm wondering what happens down the road if it needs to be replaced with a new unit that needs more amperage. the existing 10 guage wire will not be sufficient I'm thinking.