tmmccauley
Member
Table 430.22(E) indicates that for a continuous rated motor the ampacity of the cable feeding it must be twice (200%) the nameplate current rating when the motor is used for varying loads. That does not seem reasonable. If the motor is continuously rated for 20 Amperes and is supplied by a cable whose ampacity is 20 amps under the environmental conditions prevailing, why do I need a cable rated for 28 amps when the motor is running intermittently (less heat generated in the cable) and 40 amperes when the motor is carrying a varying load (less heat generated in cable)?
