Journeyman Electrician Exam (NEC)Special Occupancies, Equipment, and ConditionsHard
A new outdoor swimming pool is being installed at a residential property. The pool's circulation pump motor is rated for 2 horsepower (hp), 230 volts, single-phase. What is the minimum size, in AWG, of the copper equipment grounding conductor required for this motor circuit, assuming the overcurrent protective device is sized at 125% of the motor FLC?
- A12 AWG
- B8 AWG
- C14 AWG
- D10 AWG
Show answer & explanationAnswer & explanation
Correct answer: A. 12 AWG
First, find the FLC for a 2 hp, 230V, single-phase motor from NEC Table 430.248, which is 12A. The OCPD is 12A * 1.25 = 15A. According to NEC Table 250.122, for an OCPD of 15A, the minimum size copper equipment grounding conductor is 14 AWG. However, NEC 680.21(A)(4) specifically requires that the equipment grounding conductor for pool motors shall not be smaller than 12 AWG copper, or be installed in a raceway.
Why the other options are wrong
- B. 8 AWG is larger than required by NEC 680.21(A)(4) for this motor.
- C. 14 AWG would be correct based solely on Table 250.122 for a 15A OCPD, but NEC 680.21(A)(4) overrides this for pool motors, requiring a minimum of 12 AWG.
- D. 10 AWG is larger than required by NEC 680.21(A)(4) for this motor.
Pool Motor EGC Sizing
Equipment grounding conductors for swimming pool motors must be a minimum of 12 AWG copper, regardless of the overcurrent protective device size, as per NEC Article 680.
- Specific requirement for pool motors (NEC 680.21(A)(4)).
- Overrides general EGC sizing rules (NEC 250.122).
- Applies to all pool pump motors for enhanced safety.
Memory trick: Pool motors: 'Twelve' gauge for ground, always safe around water.