What protection does the Code require for a 120-volt, single-phase, 20-ampere branch circuit supplying a permanently installed swimming pool pump motor?
- AArc-fault circuit interrupter protection installed at the panelboard
Arc-fault protection targets arcing faults in branch circuit wiring, largely in dwelling living areas. It does not address the shock hazard from a leaking pump motor winding.
- Ground-fault circuit interrupter protection for the outlet that supplies the motor
- CA surge protective device installed ahead of the motor controller
Surge protection guards equipment against transient overvoltage. It offers no protection to a person in contact with a faulted pump.
- DAn isolated equipment grounding conductor run back to the service
An equipment grounding conductor must be run with the circuit, but the term isolated has a specific and unrelated meaning, and no version of it substitutes for ground-fault protection of personnel.
Why B is correct
Ground-fault circuit interrupter protection is what the Code requires here, and it follows the outlet whether or not a receptacle is involved. Pump motors sit outdoors, take weather and chemical exposure, and are handled by people who are wet, so a device that opens on a few milliamperes of leakage is the appropriate protection.
What this question is testing
This checks whether you know that ground-fault protection at a pool attaches to the outlet rather than to the receptacle, so hard-wired equipment is covered right along with cord and plug connected equipment. It is a persistent field misconception that direct connection avoids the requirement, and the exam uses the pump motor to test exactly that assumption.
On the job
The classic service call is a pool pump that trips after a heavy rain, or an older pool where a tech installs a replacement motor on an unprotected circuit because that is how he found it. Replacing the motor is exactly the moment the protection has to be brought up to current requirements. Tripping is usually a genuine problem rather than nuisance: moisture in the motor, a damaged whip, or a failing start capacitor, and it is worth chasing rather than defeating.
Memory technique
Water plus motor equals GFCI, plug or no plug.
Exam tip
At a pool, assume ground-fault protection is required and look for the exception rather than the other way around.
Where to look it up
680.21(C) covers pool pump motors; 680.22 covers receptacles, lighting, and other outlets in the pool area.