What wire do you need to run from a 35 amp breaker. The application is for an air conditioner.

Never seen any ac run on a 35 amp? Usually 30 or 40. What size is the unit? Best bet is to go 40 amp 8 wire

It's a commercial unit the label said 43.1 amp

Read the A/C nameplate; there are special rules for A/C units that allow for smaller wire than typical rules of #10/30A, #12/20A, #14/15A, etc. the nameplate will tell you max breaker size and min wire size. Due to large startup/surge current. A/C's compressor should have an internal overload to protect the smaller wire while running...