**A steady 21-amp reading deserves checking, but those two numbers alone don’t establish a problem.** It’s about 19% above the tag’s 17.6 amps.

Assuming “RL” means **RLA—rated load amps**, that value is used for electrical component sizing. The compressor’s allowable maximum continuous current can be higher; the exact limit depends on its model. [Copeland’s explanation of compressor current ratings](https://copeland.custhelp.com/app/answers/detail/a_id/5342).

The measurement matters:

- **During startup:** A brief current surge is expected.
- **While running steadily:** Have an HVAC technician compare the reading with the manufacturer’s specifications and check operating voltage, condenser airflow, and refrigerant pressures.
- **Measured at the outdoor unit’s supply:** The reading includes the fan’s current, which affects comparison with the compressor tag.

**Turn it off and arrange service if it trips the breaker, repeatedly shuts down, smells burned, or hums while failing to start.** Avoid further checks inside the energized electrical compartment; capacitors can retain a charge after power is disconnected. [Copeland’s safety guidance](https://webapps.copeland.com/online-product-information/Publication/LaunchPDF?Index=AEB&PDF=1154).

Was the 21 amps measured during steady operation, and was it measured on a compressor wire or the whole unit’s supply? What’s the compressor’s make and model?