A generating set — comprising an engine and an AC generator mounted on a common base — is generally classified as a generating set rather than as a standalone generator or engine. The applicable heading depends on the type of prime mover (e.g., spark-ignition, compression-ignition, or gas turbine). Importers should confirm the combined-unit classification with their customs broker, as it differs from the standalone generator heading.

CBP and trade counsel typically look for rated output in kVA or kW, number of phases (single or three), rated voltage and frequency, power factor, and whether the unit is a synchronous or asynchronous (induction) type. For very large machines, the cooling method (air, hydrogen, or water) and insulation class may also be relevant. Providing a complete OEM datasheet with the entry package reduces the risk of examination delays.