What is the minimum ampere rating for a disconnecting means that serves a hermetic refrigerant motor compressor?

The correct answer regarding the minimum ampere rating for a disconnecting means that serves a hermetic refrigerant motor compressor is defined by the National Electrical Code (NEC) and is based on ensuring the safe and effective operation of the compressor. The NEC specifies that the disconnect means should be rated at a minimum of 115% of the nameplate rated load current.

This percentage allows for the additional current that may be drawn during startup conditions, as hermetic refrigerant motor compressors typically have higher inrush currents upon activation compared to their steady-state operational load. By ensuring that the disconnect means can handle this additional current, it prevents tripping during normal operation while providing adequate protection for the equipment.

Understanding the rationale behind this requirement is crucial. It takes into account the operational characteristics of hermetic compressors, including their ability to handle various loads while ensuring safety and reliability in electrical installations. The other options suggest a disconnect rating lower than 115%, which would not adequately accommodate the potential inrush current experienced during start-up, leading to potential nuisance tripping and increased risk for the equipment.