On Mar 3, 8:57*pm, bob haller wrote:
On Mar 3, 8:22*pm, Mikepier wrote:

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.

normally a new install like a replacement AC will get all new wring
and service disvconnect.

Not around these parts. Unless the wiring is too small,
deteriorated, etc. If not, then typically just the disconnect
box on the exterior is changed.




a new 8 gauge copper line with new disconnect
by the compressor will see less voltage drop, a good thing.

but new compressors will likely be more efficent and run with less
current.

if everything is open then this is the best time to upgrade, and if
breaker space is available run a couple 20 amp lines to work boxes for
future use if needed. I did that once and a few years later was glad I
did when we decided to install a new kitchen

Why can't you just add those later, when and if needed?
It's easier to just connect new wires to new breakers rather
than install boxes, deal with splices, etc.