Just had annual maintenance, so a bit suspicious... Have a heat pump in the attic, and an A/C unit outside. Since service call, when the system is turned on at the thermostat, the circuit breaker trips after a few minutes. Heat pump continues to run.

Do you mean you have a heat pump with an air handler in the attic?
Do you mean that the circuit breaker to the air handler in the attic trips when system comes on?

If so either call technician back, or go up to the attic and open air handler. Look for bare wire, pinched wire or missing wire nut in high voltage wiring between relay and fan. Should be pretty obvious.

Thanks. Yes, heat pump/air handler in the attic and central A/C unit outside. Circuit breaker to the A/C unit trips. Main GFCI is also tripping, but not every time the breaker trips. My electrician is coming tomorrow. Since he doesn't normally work on A/C units, it will be helpful for him to have some things to look for.

Have the same service people back and ask them what they did to your unit.

Hui