Fundamental Guide to Ground Fault Circuit Interrupter

Fundamental Guide to GFCI

Electricity is essential to modern life and every residential, commercial, or industrial building. It's basically what keeps everything running, and we are all dependent on it. Electricity is so important that it cannot be underestimated, and in the same way, its danger cannot also be taken for granted.

More than 20,000 workers have been injured in workplace electrical accidents over the past ten years. Although electrical hazards are not the major cause of workplace injuries and accidents, they are undoubtedly fatal and costly. These injuries and accidents can disrupt the lives of the workers and their families, affect employees' productivity, and cause significant damage to the company. This is the reason why Occupational Health and Safety Administration (OSHA) has been very strict with implementing electrical safety procedures such as Lockout Tagout in a workplace.

Electrical accidents happen not only at the workplace but even at home. An estimated 51,000 electrical home structure fires occur every year, resulting in property damage of more than $1.3 billion (National Fire Protection Association, 2003-2007). Additionally, the U.S. Consumer Product Safety Commission reports around 400 electrocution injuries in the U.S. each year.

One of the most common reasons for electric shock is a ground fault that can exist even with proper wiring and fusing circuit-breaking equipment. Its consequences can be devastating, but there are things we can prepare against them. This is where the role of GFCI comes in. To better understand GFCI, let's start this article by understanding Ground Fault first.

What is a Ground Fault?

A ground fault happens when electricity takes an unplanned path to the ground. The current drastically and quickly increases, leading to tripping of the breaker. Ground faults can be caused by damage to the appliances, incorrect wiring, or poor or worn wire insulation. These are most dangerous in areas that usually experience high moisture, such as a bathroom, kitchen, or garage.

There are times when the chosen path to the ground is outside the appliance, and when someone unknowingly touches it, an electrical shock occurs. Electrical shock is the most common hazard, but it can also lead to fires and burns. An easy yet great measure against them is adding a GFCI or Ground Fault Circuit Interrupter to your electrical circuits to prevent and stay safe from ground faults.

What is a Ground Fault Circuit Interrupter?

A Ground-Fault Circuit Interrupter (GFCI) is a fast-acting circuit breaker that measures and compares the current, both input current and output current. When it detects even a slight imbalance in the circuit caused by current leakage to the ground, the outlet disconnects electricity within 20-30 milliseconds. With this, it prevents electric shock or electrocution. It also mitigates electric fire and stops electricity in damp environments, preventing undesired accidents. This is the reason why Occupational Safety and Health Administration (OSHA) requires companies to include GFCI in their program to protect workers and prevent fatal electrical accidents.

All areas exposed to moisture require GFCI protection. Although GFCI can be helpful in any area of your home or workplace, areas where water may be present, are more of an electrical hazard than dry areas. In general, Ground Fault Circuit Interrupter should be installed in areas at home such as the kitchen, bathroom, laundry areas, garage, and outdoor areas should be equipped with GFCI protection

On the other hand, it is critical for the workplace to provide GFCI on job sites for receptacle outlets in use and not as a part of the building's permanent wiring. A company must give the approved GFCIs for all 120-volt, single-phase, 15-and 20-ampere receptacle outlets on construction areas that are not part of the permanent wiring of the building that is in use by the employees. If there is any receptacle installed as part of the permanent wiring of the building, then the company must provide GFCI protection.

What are the types of GFCI?

GFCIs are usually available in three different types: cord-connected type, portable, and receptacle. Each one has its own distinctive function and work.

1. Cord-connected type GFCI

It is an attachment plug which protects the cord and any electrical equipment attached to the cord. Similarly with portable type GFCI, it embodies a no-voltage release device that will disconnect power from the source if any supply conductor is open.

2. Ground Fault Circuit Interrupter Receptacles

These are commonly used as standard receptacles. It is placed inside regular outlet boxes, and it protects you against portable electrical device faulting. These devices are pretty popular because of their low cost.

3. Portable GFCIs

This type of Ground Fault Circuit Interrupter can be used in place of permanent Ground Fault Circuit Interrupter outlets. It can plug into a standard receptacle and come in numerous forms, such as extension cords or a simple box directly plugged into an electrical outlet. Portable GFCIs also incorporate a no-voltage device that can disconnect current to the outlets if any current conductor is open.

Installation and Testing of GFCI

Installation and testing of GFCI are vital for both the workplace and home. Although portable GFCIs do not require an electrician for installation, a licensed electrician should install a receptacle and circuit breaker. 

Ground Fault Circuit Interrupter must be tested monthly to ensure safety and functionality. To test the GFCI receptor, simply plug lamps into the receptacle and hit TEST. Once it is done, the GFCI RESET button will appear, and the light should disappear. During this time, if you notice that the light is not going out while the RESET button is popped out, it means the receptacle was installed incorrectly. Another thing, if the button does not come out and the light does not come on, your receptacle might be damaged, and you should consult an electrician.

Note, however, that you can always rely on a licensed electrical technician to inspect and assess the ground fault. It would still be best to hire licensed professionals as they would perform all the assessment work and fix any issues that might hinder its functioning and will also make it work effectively.

GFCI Facts

For years, GFCI has been preventing electrocutions and accidents. In fact, since the introduction of GFCI protection in 1975, there has been an 80% drop in electrocutions. Also, between 1975 and 2020, there was a 93% drop in consumer product electrocutions.

Now, if you will ask, what if GFCI protection was not required? Studies show an estimated 603% increase in electronic shocks and a 1,118% increase in consumer product electrocutions if GFCI protection was not required.


A Ground Fault Circuit Interrupter is designed to prevent electric shocks and its impending dangers. Since the 1970s, GFCIs have saved thousands of lives and helped reduce electrocution accidents. However, despite the presence of GFCI, electrocution remains the fourth leading cause of work-related fatalities for construction workers. There is a record of at least one workplace electrocution accident in the U.S. every day. Hence, GFCIs should be regarded just as important as smoke detectors.

Not only that, companies should also be aware and be able to address the electrical equipment hazards and violations by implementing and using electrical safety procedures. This way, we are not only saving the lives of the workers, but we are also protecting the families of the workers and the company itself.

The material provided in this article is for general information purposes only. It is not intended to replace professional/legal advice or substitute government regulations, industry standards, or other requirements specific to any business/activity. While we made sure to provide accurate and reliable information, we make no representation that the details or sources are up-to-date, complete or remain available. Readers should consult with an industrial safety expert, qualified professional, or attorney for any specific concerns and questions.


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Author: Herbert Post

Born in the Philadelphia area and raised in Houston by a family who was predominately employed in heavy manufacturing. Herb took a liking to factory processes and later safety compliance where he has spent the last 13 years facilitating best practices and teaching updated regulations. He is married with two children and a St Bernard named Jose. Herb is a self-described compliance geek. When he isn’t studying safety reports and regulatory interpretations he enjoys racquetball and watching his favorite football team, the Dallas Cowboys.