Larry Bohn
Member
- Location
- ashland, oregon
Motor branch circuit conductors for a continuously loaded motor shall be sized at 125% of the NEC table values, Art. 430.22. Article 210.19 says that conductors shall be sized at 125% of the continuous load, or, the load after any temperature and conduit fill derates are applied. Pretty straightforward and easy to explain.
My question is: if motor conductors are required to be sized at 125% of the motor current taken from the NEC tables, does this minimum 125% apply to any derating or calculations in 210.19? In other words, can I ignore the minimum 125% required by 430.22 when derating and calculating conductor size as I would for branch circuits in 210.19, or do the conductors need to maintain a minimum ampacity of 125% of the motor load AFTER derates are applied?
The blue explanatory text in the handbook implies that motors, since they have overload protection sized greater than the full load current of the motor, and overcurrent protection sized greater than would otherwise be applied in a non-motor application, this minimum 125% shall be maintained after derating.
My question is: if motor conductors are required to be sized at 125% of the motor current taken from the NEC tables, does this minimum 125% apply to any derating or calculations in 210.19? In other words, can I ignore the minimum 125% required by 430.22 when derating and calculating conductor size as I would for branch circuits in 210.19, or do the conductors need to maintain a minimum ampacity of 125% of the motor load AFTER derates are applied?
The blue explanatory text in the handbook implies that motors, since they have overload protection sized greater than the full load current of the motor, and overcurrent protection sized greater than would otherwise be applied in a non-motor application, this minimum 125% shall be maintained after derating.