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Why GFCIs Make Homes Safe

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In 1971, the National Electrical Code added a landmark safety requirement that would save thousands of lives and cut home electrocutions by 50%.

What was the key addition?

Ground fault circuit interrupters, or GFCIs for short, are inexpensive electrical devices designed to protect people from severe or fatal electric shocks. In fact, the Electrical Safety Foundation International (EFSI) provides a couple of fast facts that demonstrate the importance of working GFCIs.

  • GFCI's shut off electric power in the event of a ground fault within milliseconds.
  • 26% of respondents who tested GFCI receptacles discovered one that was not working.
  • In the United States, arcing faults cause about 30,000 home fires each year, resulting in hundreds of deaths and injuries and more than $862 million in property damage.

GFCIs have played a key role in reducing electrocutions and greater use of GFCIs would help mitigate thousands of electrical burns and shock injuries that continue to occur in homes every year.

To help homeowners understand GFCIs and how they work to reduce serious injuries, please find some common questions to explain these inexpensive, yet important devices.

What is a GFCI?

A ground fault circuit interrupter (GFCI) is a device that shuts off an electric power circuit when it detects that current is flowing along an unintended path, such as through water or a person.

Ground fault protection is integrated into GFCI receptacles and GFCI circuit breakers for installation into an electrical system. Ground fault protection is particularly important for circuit outlets in areas where electrical equipment is near water (such as bathroom or kitchen sinks).

What Does Ground Fault Mean?

A ground fault is an unintentional electrical path between a power source and a grounded surface. Ground faults most often occur when equipment is damaged or defective, such that live electrical parts are no longer adequately protected from unintended contact.

Many home electrocutions, burns and shocks occur when a ground fault is not in place. If your body provides a path to the ground for this current, you could be burned, severely shocked or electrocuted.

How Does a GFCI Prevent Electrocutions?

A GFCI constantly monitors the current flowing through a circuit and opens a circuit when it detects an imbalance between the incoming and returning current. This imbalance triggers a shutoff in as little as 1/40th of a second.

GFCIs are most frequently used in wet locations, construction sites or other high-risk areas to interrupt the flow of electricity within as little as 1/40 of a second to prevent electrocution.

How Do GFCIs Work?

A GFCI is subtle.

In the US, most homes have 120-volt outlets, where there are two vertical slots (with the left slot slightly larger than the right slot) and then a round hole centered below them.

  • The left slot is called "neutral"
  • The right slot is called "hot"
  • The center hole is "ground"

How a GFCI Detects a Dangerous Current

In properly working appliances, the electricity flows from hot to neutral and the GFCI monitors the amount of current flowing from hot to neutral. If there is any imbalance, it trips the circuit to stop the flow of electricity.

For example, if you are outside with a power drill completing a project as it starts raining, you are standing on the ground. Since the drill is wet, there is a path from the hot wire inside the drill through you to ground. If electricity flows from hot to ground through you, it could be fatal. The GFCI can sense the current flowing through you because not all of the current is flowing from hot to neutral as it expects...some of it is flowing through you to ground. As soon as the GFCI senses that, it trips the circuit and cuts off the electricity.

How to Test GFCIs?

Homeowners should test all GFCIs every month, which provides a baseline testing requirement recommended by both the ESFI and most manufacturers. However, if the instructions are not readily available, here is a commonly accepted procedure.

  • Plug a lamp into the outlet and turn the lamp on.
  • Press the GFCI's test button.

Did the light go out? If not, the GFCI is not working or has not been correctly installed and you should contact a qualified electrician to correct the wiring and/or replace the defective GFCI.

If the light went out, press the reset button. Did the light come back on? If not, replace the GFCI. If the light came back on, then the GFCI is working appropriately.

Here is a video of GFCI testing instructions from the ESFI.

Where Should GFCIs Be Installed?

A GFCI should be used in any indoor or outdoor area where water may come into contact with electrical products. For reference, the National Electrical Code GFCI requirements (and effective date):

  • Underwater pool lighting (since 1968)
  • Receptacles:
    • Outdoors (since 1973)
    • Bathrooms (since 1975)
    • Garages (since 1978)
    • Kitchens (since 1987)
    • Crawl spaces and unfinished basements (since 1990)
    • Wet bar sinks (since 1993)
    • Laundry and utility sinks (since 2005)

Georgia adopted the 2023 NEC effective January 1, 2025. If your home was built or last rewired before these updates, a licensed electrician can assess whether your current GFCI coverage meets today's standards.

Consider portable GFCIs whenever operating electrically-powered garden equipment (mower, hedge trimmer, edger, etc.) or electric tools (drills, saws, sanders, etc.) for do-it-yourself work in and around the house. Unlike fixed receptacles, portable GFCIs plug directly into any standard outlet and extend ground fault protection to devices that would otherwise be unprotected.

Can I install GFCIs Myself?

No. The ESFI advises that GFCIs should only be installed by a licensed, qualified electrician.

However, portable GFCIs require no tools for installation and are an excellent DIY option. They plug directly into any existing outlet and extend GFCI protection to the devices that are connected. This protection makes them ideal for outdoor use, workshops, and job sites where a fixed GFCI receptacle hasn't been installed.

Frequently Asked Questions About GFCIs

How often should I test my GFCI outlets?

The GFCI testing requirement recommended by both the Electrical Safety Foundation International (ESFI) and most manufacturers is once per month. The test takes under a minute. Simply plug a lamp into the outlet, press the TEST button, and confirm the light goes out. Then press RESET and confirm the light comes back on. If the outlet doesn't respond correctly at either step, the GFCI is faulty and should be replaced by a licensed electrician. It's also worth testing all GFCIs after a power outage or electrical surge.

What's the difference between a GFCI outlet and a GFCI breaker?

Both provide ground fault protection, but they work at different points in your electrical system. A GFCI outlet (also called a GFCI receptacle) is installed at a single outlet location and can be wired to protect other outlets downstream on the same circuit. A GFCI breaker is installed in the electrical panel itself and protects every outlet and device on that entire circuit. No individual GFCI receptacles needed. GFCI breakers are common in older homes being updated to current code, or in situations where a single breaker can protect a large area like a garage or outdoor circuit. A licensed electrician can help determine which solution makes more sense for your home.

Can one GFCI outlet protect multiple outlets on the same circuit?

Yes, this is one of the most useful and least understood features of GFCI outlets. When wired correctly using the LOAD terminals (rather than the LINE terminals), a single GFCI receptacle can provide ground fault protection to every outlet downstream on the same circuit. This is how electricians bring older homes up to code efficiently by installing one GFCI outlet near the panel or water source and extending that protection through the rest of the circuit. If you're unsure whether your existing GFCIs are protecting the full circuit or just a single outlet, a quick electrical inspection can confirm coverage.

Have More Questions About GFCIs or Your Home's Electrical Safety?

GFCIs are one of the most cost-effective safety upgrades available for any home and understanding how GFCIs operate and fit into your electrical system puts you in a much better position to protect your family. If any of your GFCI receptacles failed the monthly test, if your older home is missing GFCIs in required locations, or if you'd simply like a licensed electrician to conduct a full electrical safety inspection, Snappy Electric, Plumbing, Heating & Air is here to help.

If you have any questions or would like to install any GFCIs, call us or request a free electrical safety inspection. Our licensed Marietta electricians will make sure your GFCIs and the rest of your electrical system are working exactly as they should.