GFCI: Ground Fault Circuit Interrupter. Types, Working & Applications

What as a GFCI (Ground Fault Circuit Interrupter) and How Does it Work?

At home or outside, we cannot do without electricity and electrical devices. These are indispensable necessities in our modern lives. However, their accidental contact can give a painful shock, resulting in serious injuries, and, sadly, sometimes even fatal consequences. That’s why we are talking about a special protective device known as GFCI.

Related Posts:

• AFCI: Arc Fault Circuit Interrupter. Types, Working & Applications
• Difference Between GFCI and AFCI

Causes of Electrical Hazards

• Apart from ever–increasing use of electrical power and outdated home electrical systems lacking capacity to handle modern electrical appliances and devices, wiring hazards are a major cause of electrocutions and home fires.
• Misuse of surge suppressors, power strips and extension cords is also a cause of electrocutions and fires.

Don’t worry: Electrical Hazards are avoidable!

Incidents of electrical shock are avoidable for sure. For making electrical devices “shock free” and eliminating chances of fires, electrocutions and injuries to users, all one needs to do is eliminate electrical hazards with affordable devices.

Ground Fault Circuit Interrupters (GFCIs): Shield against electrical hazards.

• When it comes to preventing electrical fires and keeping your family members especially kids safe, a GFCI is the top home safety device to have.
• No home is safe without proper wiring. Properly installed and used GFCIs form an important part of household electrical safety.

Related Post: How to wire a GFCI Outlet? – GFCI Wiring Circuit Diagrams

What is a GFCI?

• A GFCI (Ground Fault Circuit Interrupter) is an automatic device that offers personal protection against lethal electrical shock or electrocution.
• It is a special electrical receptacle or outlet that can stop electrical power within milliseconds as a safety precaution.

Let’s see how?

• It trips electrical circuits whenever it detects ground faults or leakage currents. When a person’s body starts to receive a shock, the GFCI senses it and cuts off the power before any injury can occur.
• In general, GFCIs are installed wherever there is the potential for contact between a person and an electrical appliance in or near moisture, water, or water pipes.
• One needs to ensure that GFCIs are installed in his or her kitchen, bathrooms, workshop, basement, garage, swimming pools, hot tubs, outdoor outlets and fixtures, and any other areas where water and electricity are likely to come in contact.
• GFCIs are especially useful for cord-connected appliances and equipment used outdoors or near water.

Related Post: How to Wire GFCI Combo Switch and Outlet – GFCI Switch/Outlet Wiring Diagrams

How Does a GFCI Work?

• Simply put, usually a normal electrical outlet has two vertical slots and a round hole just below them. The larger “left slot” corresponds to “neutral and “right slot” is called “hot”. The third, round hole is the “ground”.
• Normally, electricity flows from hot to neutral in the outlet. The GFCI works by measuring the current leaving the hot side of the power source and comparing it to the current returning to the neutral side.
• If they are not equal, this means that some of the current is flowing along an unintended path possibly through water or through a person.
• The GFCI detects imbalance in the current flowing from hot to neutral, imbalance in the current flowing from hot to neutral and quickly cuts off electricity, thus reducing the risk of electrical shock.
• The sensor inside a GFCI detects the difference between the current flowing to the appliance and the current flowing from the appliance.
• If the electricity flowing into the circuit differs by as small as 4 or 5 milliamps from that returning, a GFCI quickly turns off all power by tripping a relay within it within a few hundredths of a second, much before the user hardly feels the shock.
• When the problem is corrected, GFCI’s can later be reset to restore power to the affected circuit.
• If the problem still exists and GFCI continues to “sense” the difference in the amount of electricity flowing into the circuit to that flowing out, it will not reset.

Related Post: Wiring of the Distribution Board with RCD (Residual Current Devices)

Types of GFCIs

Three types of GFCIs are commonly used in homes – the GFCI outlet, the GFI circuit breaker and the portable GFCI. All of these GFCIs perform the same function but each has different applications and limitations.

1.  The GFCI Outlet:

It is like a standard electrical outlet and protects any appliance plugged into it. The GFCI outlet can also be wired to protect other outlets that are connected to it.

2.  GFCI Circuit Breaker:

It controls and protects an entire circuit, and is installed as a replacement for a standard circuit breaker in a home’s main circuit board. Compared to multiple GFCI outlets, one GFCI circuit breaker can protect the entire circuit which may include all bathrooms or all outdoor fixtures.

Precautions to take: The GFCI circuit breaker should match the requirements of main electrical panel. For an older panel that utilizes fuses, GFCI outlets must be used instead of a GFCI circuit breaker.

3.  Portable GFCI:

It is used for mobile applications and can work as well as the ones installed in a house. Portable GFCIs are frequently used by contractors on worksites. But Portable GFCI protection could also be put to use whenever electrically-powered equipment is used in garden related works and when using electric tools in and around the house.

Precaution to take: Portable GFCIs should not be used in place of permanent ones in home. They are intended to be used only in situations where you must bring power from an unprotected outlet into a hazardous situation.

• Related Post: How to Wire a GFCI Circuit Breaker? 1, 2, 3 & 4 Poles GFCIs Wiring

Applications of GFCI

The National Electrical Code (NEC) requires GFCIs to be installed at following spots at home and outside:

• Underwater Pool Lighting
• Outdoor Receptacles
• Bathroom Receptacles
• Garage Receptacles
• Kitchen Receptacles
• Crawl Spaces
• Unfinished basements
• Wet Bar Sinks
• Laundry Receptacles
• Utility Sinks

NEC Code Requirements for GFCI

The NEC Code Requirements for GFCIs are aimed at providing protection to anyone who plugs into an electrical system. As per the NEC Code, the installation of GFCIs is a must in following areas:• 210.8(A) Dwelling Units

• 210.8(A) Dwelling Units
• 406.3(D)(2), (3) Receptacle Replacement
• 424.44(G) Electric Space Heating Cables
• 511.12 Commercial Garages
• 517.20(A) Healthcare Facilities
• 525.23 Carnivals, Circuses, and Fairs
• 527.6 Temporary Installations
• 547.5(G) Agricultural Buildings
• 555.19 Marinas and Boatyards
• 680.32 Swimming Pools, Storable
• 680.62 Therapeutic Tubs
• 680.71 Hydromassage Bathtubs
• 620.23, 620.85 Elevators and Escalators
• 680.43, 680.44 Spas and Hot Tubs
• 680.22(A), 680.23, 680.27 Swimming Pools, Permanent
• 680.51(A), 680.56(A), 680.57 Fountains

Related Posts:

• How to Wire an AFCI Breaker? Arc Fault Circuit Interrupter Wiring
• How to Wire an AFCI Outlet? – Arc Fault Interrupter Outlet Wiring
  
• How to Wire an AFCI Combo Switch – AFCI Switch Wiring Diagrams

Thousands of Lives Saved:

• Since the 1970s, GFCIs have saved thousands of lives and have helped cut the number of home electrocutions in half.
• If GFCIs were installed in older homes, experts suggest 70 per cent of the electrocutions that occur each year in the home could be prevented.
• Installing a GFCI in every home and workplace could prevent nearly 70 per cent of the approximately 400 electrocutions that occur each year.

Author Bio:

Jeson Pitt is a professional electrician with a keen interest in electrical products and how they work. He spends much of his time delving into the world of new electrical technologies and innovations in the industry, polishing his skills and expertise, as well as sharing his thoughts and learnings with other enthusiasts. Jeson works as an online marketing manager for D&F Liquidators, a leading electrical products supplier in CA.

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