Accurate Review


Ground Fault Protection

An Accurate Review White Paper, Spring 2018


By:  Kevin Walsh, AIA



The Basics: Ground Fault Protection



“You need a GFI there…”


Most of us have heard, or even said, this a few times. But, what exactly does this mean, and why do I need one THERE? GFCI, or commonly shortened to GFI, is an acronym for Ground Fault Circuit Interrupter, which is typically an electrical receptacle, or outlet. These receptacles, generally distinguishable by TEST/RESET buttons located in the center of the device, detect abnormal current flow to ground and “interrupt” that flow by opening, or breaking, the circuit. This abnormal flow of current is detected by monitoring the input (hot) current compared to the output (neutral) current of the receptacle; a difference as little as 4-5 milliamps will “trip” the GFCI in less than 1/10th of a second.  The interruption of the circuit reduces the risk of human injury or even electrocution by halting the flow of current when the GFCI detects leaked current.


NFPA 70, the National Electric Code, states that all 125 volt, single-phase, 15 and 20 amp receptacles installed in or near areas subject to moisture shall be GFCI protected. Such areas include bathrooms, outdoor areas, garages, laundry areas, kitchen counter, unfinished basements/crawls, and also within 6ft of sinks, bathtubs, and shower stalls regardless if they’re in the same room or not.  Refer to NEC 210.8 for additional information regarding required locations. Certain appliances also require GFCI protection such as drinking fountains, vending machines and dishwashers. Outdoor areas will typically require the use of a weather proof cover over the GFCI receptacle.


One thing to understand is that a receptacle may be GFCI protected even if the receptacle itself is not a GFCI device. Where there is a GFCI receptacle, any device “downstream” of that device is also protected by the GFCI. When inspecting areas such as kitchen counters, it is important to understand and verify the extent of the GFCI protection. Additionally, GFCI breakers may be found in the panel-box, which protects all devices within that circuit.


All GFCI intended for protection of personnel shall be listed and conform to the UL 943 Standard for Ground Fault Circuit Interrupters. An Underwriters Laboratory stamp should be on the listed device, although it may not be visible when the cover plate is installed. New provisions of the UL 943 standard require that newly installed GFCI receptacles prevent current flow when the receptacle becomes faulty. No pun intended; ok, maybe slightly. However, many existing GFCI receptacles may not have that capability. Therefore, GFCI receptacles should be tested monthly to ensure proper operation and protection due to early GFCI receptacles losing the ability to interrupt the circuit properly overtime. There are a couple ways to test GFCI receptacles. First, plug a night light or similar appliance into the GFCI protected receptacle and press the TEST button, the appliance should no longer work until the RESET button is pressed. This indicates a functioning GFCI protected receptacle; if the test failed, the GFCI should be replaced. Second, inspectors typically carry a GFCI circuit tester that can also be used to test the GFCI functionality of a receptacle.  These testers are found a many home improvement stores and the manufacturer instructions should be followed to ensure reliable testing.


As always, safety is the number one concern when it comes to electrical installation and inspection. The National Electric Code is intended for “the practical safeguarding or persons and property from hazards arising for the use of electricity.”  Only trained and qualified persons shall work on or inspect electrical system.  When in doubt, call a professional.










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