Responded to a no a/c call on a Trane package heat pump HVAC unit where the breaker was tripping on the unit, starting amps were 40.8 amps, running amps 8.1. Checked electrical connections at the unit, disconnect and the breaker box. Black wire on the breaker was a little loose. The breaker could be bad, suggest finding an electrician to replace breaker or upgrade the entire box. Call the office for a suggested electrician if you don’t have one