Gas and Oil Home Heating Furnaces - 8/2 wire for heatpump

In building a house would 8/2 with a ground,, be good for wiring a 3 1/2 ton unit? the inside and outside units? thanks, David

I believe 10/2 is adequate for outdoor and indoor units. Exclusive of the electric backup circuit which usually requires a 60amp breaker. So you could use the 8/2 if you alrerady have it.

I would say look at the paper work that comes with the unit or the hvac should tell you yes or no. Dont forget on how far the unit will be from the panel. You have to look at that also.;) ED

by amp draw of the appliance and length of wire. 8/2 is recommended by several mfrs for 3.5 tons, generally see 10/2 on 3 tons and below

look on the components for a model tag. On this tag is listed the minimum circuit amps required for each piece and the maximum fuse/circuit breaker allowed for the component. Then use the wiring appropriate for the minimum circuit amps. Keep in mind the wiring for each component of any heat pump is required to be on it's own separate circuit and that the wiring for each component should NEVER BE SIZED FOR LESS than the minimum circuit amps allowed for that component. (Our company sizes wiring to the maximum fuse/circuit breaker allowed for an added margin of safety) Should your wiring exceed 75 ft. we recommend using the next wire size up. If you not sure your wiring is appropriate, it would be wise to consult with a licensed experienced electrician or HVAC installer in your area as they will be familiar for what is required by your local codes.