NJ is correct that you must use the ampacity and fuse ratings on the unit's data plate to size the feeder. However, the info from the online conversion table may be misleading in regard to your question. In practical A/C application, 1 ton = 12,000btu = 1h.p. compessor motor. Therefore, a 12 ton A/C would have a 12 h.p.(approx.)compessor or two 6 h.p.compressors.
The term "ton" comes from an early measurement of a system's capacity to reject heat. A one "ton" system would reject enough heat to melt a "ton" of ice in 24 hours.
