I am getting ready to hang drywall in my basement but before I do that, I need to run wire from the main panel upstairs to the future location of the central AC furnace through the basement ceiling joists. I do not know yet who will be installing my AC but I will probably outsource it. At this point I just need to know what the electrical requirements for AC are so that I can bring the cable and hang the drywall. The house has three bedrooms and two living rooms, 1800 sq ft, two floors.
What amperage/AWG am I looking at? The wire distance from the panel to the furnace is only about 20' +/- and then I plan to sit the condenser on the roof (it is a low pitched mod bit roof so I can do this, many of my neighbors with similar homes do) directly above the furnace, two floors above (so another 16-20' total). It also may be worth mentioning that I plan to use this for just AC and not heat — I have already a radiator system in place and I love radiant heat.
Best Answer
It's going to completely depend on the unit that's being installed, but commonly it'll be 30-60 amp with 10-4 AWG wire. You're probably looking at a 3.5 ton unit, so you'll be in the 30-40A (10-8 AWG) range. It might be worth it to get a few quotes from local HVAC companies, and see what they want to install. The companies may have a preferred breaker and wire size, so they may want to redo any work you do anyway.
Don't forget you'll also need high and low pressure tubing, and control wires between the indoor and the outdoor units.