A-B series 193 motor overloads come equipped with wire stubs to attach them to A-B motor starters. I measure these to be 12 ga. solid wire.
How can an overload with a range of 12 to 32A be fed with 12ga. wire?
(The trip point is 120% of dial setting, according to the label on the side of the OL case.)
Table 310.16 (2002NEC) shows 12AWG THHN rated at 90 deg C to have an ampacity of 30A*.
This table refers to 240.4(D) with the asterick.
Table 240.4(G) refers to Article 430, Parts III, IV, V, VI, & VII for motor and motor control circuit conductors.
How, when, the calculations for sizing branch circuit conductors for, let's say, a 20hp 460V 3ph AC Induction-Type Squirrel Cage motor with a FLC of 27A (from Table 430.150 2002 NEC), multiplying by 120% gives us a value of 32.4A. Refering to Table 310.16 shows 12AWG copper THHN rated 90deg C as 30A allowable ampacity.
It appears to me that 10AWG would be required for branch circuit conductors, so, how can the Overload device be used as supplied with 12AWG and a max setting of 32A. (And a trip setting of 120% of indicated dial setting.)
Am I wrong here?
