What Happens If the GFCI Trips? New protection requirements for outdoor outlets in dwellings

Shutterstock / Paradise on Earth
Shutterstock / Paradise on Earth
Published On
Nov 15, 2021

Ground-fault circuit-interrupter (GFCI) protection for outdoor outlets has been a requirement in the National Electrical Code since 1971, but it was limited to 15A and 20A, 120V receptacles. With the acceptance of the 2020 NEC , 210.8(F) now requires all single-phase branch circuits rated at 150V or less to ground and 50A or less and located outdoors for dwelling units to have GFCI protection for personnel. This is a major change in the 2020 NEC that many electricians and electrical contractors may miss at first.

What prompted this change? I asked myself this question when I first noticed this major change in the GFCI requirements for dwelling units. What technical substantiation was given that there was a danger to the public from these larger receptacles and the load supplied by these outlets? Since this GFCI requirement applies to all 50A and smaller outlets rated at 150V or less to ground, was testing done to air conditioning units, such as heat pumps, split units or other similar heating and cooling equipment, as well as other larger outdoor electrical equipment?

One of the key issues here is the use of the word “outlets” in the requirement. The term “outlet” is defined in Article 100 as “a point on the wiring system at which current is taken to supply utilization equipment.”

Not all outlets are receptacles

As pointed out in the NEC Handbook’s commentary on the term “outlet,” the term is often frequently misused within the electrical industry to apply only to receptacles. A receptacle is certainly an outlet, but not all outlets are receptacles. There are lighting outlets, appliance outlets and smoke alarm outlets, just to name a few. An air conditioning unit disconnecting means is technically considered to be an outlet, since the disconnecting means is supplying use equipment.

In the 2017 NEC , 210.8(C) required GFCI protection to be provided for “outlets” not exceeding 240V that supply boat hoists installed in dwelling-unit locations, such as dwelling-unit docking facilities. This requirement for GFCI protection of dwelling-unit boat hoists has been moved to 555.9 in the 2020 NEC but still applies to any boat hoist outlet, such as a receptacle outlet or a fusible or nonfusible disconnecting means. A GFCI receptacle could be used for the boat hoist, or the disconnecting means with a GFCI circuit breaker at the panelboard could be used.

Leakage of 4–6 milliamps of current or more is required to trip a Class A GFCI off and remove the power to the electrical equipment. This power outage could leave the dwelling unit without air conditioning or heating. If the home is located in a part of the country where high temperatures and high humidity, or just high temperatures, are an issue, will the GFCI trip off when the air conditioning unit turns on or, in the case of a heat pump, when the heat pump goes into defrost cycle? If the GFCI trips off and the owners are gone for the day or the weekend, is the loss of power to the air conditioning unit going to be an issue?

This situation could be harmful or even deadly for any pets in the home. I know of at least one incident where the cooling system at a small pet-boarding facility located behind a home failed, and as many as 40 dogs perished in the high heat that resulted inside the building.

In addition, people who are bedridden or have certain disabilities may not be able to reset the GFCI circuit breaker in their panelboard, and the home may be subject to high temperatures until someone can respond to troubleshoot the problem.

There are many other scenarios that could occur with very adverse results due to this application. In an extremely cold environment, will the heat pump trip the GFCI, leaving the home without heat and resulting in frozen pipes and other similar issues?

One example to examine more closely is where larger outdoor pumps are required to be GFCI-protected, and this protection hasn’t been an issue with swimming pool pump motors. Temporary loss of power to a GFCI-protected swimming pool pump motor certainly wouldn’t be a safety issue, so a comparison between a swimming pool pump and an air conditioning or heating unit is ridiculous.

GFCI protection provides incredible personnel protection against electrocution, but we certainly need to ensure that inadvertent tripping due to normal operation of the electrical equipment does not occur. Testing of electrical equipment, such as air conditioning and heating equipment, should be done well in advance of requiring the use of GFCIs as found in 210.8(F) of the 2020 NEC .

About the Author

Mark C. Ode

Fire/Life Safety, Residential and Code Contributor

Mark C. Ode is a lead engineering associate for Energy & Power Technologies at Underwriters Laboratories Inc. and can be reached at 919.949.2576 and Mark.C.Ode@ul.com.

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