[franco0783]

What size of braker do I need if I have a size 10 wire for A/C

[MarkwithaK]

If you look on the information plate one the side of your condensing unit it should list the maximum current protection for your specific unit.

[codyman144]

To elaborate on what mark said, the breaker needed and wire size required depends on how many Amps the unit is rated for (draws).

For Example 15 Amps requires at least # 14
20 AMP at least # 12
30 AMP at least # 10

So if you know you need size 10 wire odds are unit draws a max of 30 Amps. But like he said it should tell you on the unit how many Amps it requires. Wire accordingly.

For simplicity I am leaving out voltage drop considerations, but if the unit is a sizeable distance from the service panel you may need bigger wire. How far away is it?

[MarkwithaK]

Most condensing units will tell you what the min. ampacity rating is as well as the max. fuse protection size.