What is the minimum ampere rating required for a disconnecting means serving a hermetic refrigerant motor compressor?

The minimum ampere rating required for a disconnecting means serving a hermetic refrigerant motor compressor is specified to be 115% of the nameplate rated load current. This requirement is based on the National Electrical Code (NEC) guidelines, which ensure that the disconnecting means can handle the inrush current that occurs when the compressor starts.

Hermetic refrigerant motor compressors typically experience a significantly higher current during startup compared to their operating conditions. By using a rating of 115%, the system ensures that there is enough capacity to manage both normal operating conditions and the peak currents generated during startup, thus preventing nuisance tripping and ensuring reliable operation.

Selecting a disconnect rated lower than this percentage risk creating potential failures or interruptions in the compressor operation, which could lead to inefficiencies or even damage to the equipment. Therefore, the 115% requirement is crucial for maintaining the integrity and performance of the refrigeration system.