Ground Fault Circuit Interrupter or GFCI are devices used to detect ground faults and leakage currents and protect against electric shock. Compared to normal outlets, GFCI outlets do not have break-away fins between the lower and upper terminals. In normal outlets, only one side terminals are connected to the power supply via a neutral wire.
The GFCI outlet, combo, or circuit breaker is able to automatically switch off the main power supply and protect against electric shock. They are mainly used in cord-connected appliances and equipment used near water and other wet outdoor surroundings.
It’s possible to connect the GFCI outlet on a switch. In this case, the light bulb and the single-way switch are connected to the load terminal of the GFCI. This way, the GFCI protects the light bulb and switch. In a normal circuit, the light switch is connected to the line terminals.
Wiring a GFCI Outlet with an Ordinary Outlet / Receptacle
When wiring a GFCI outlet with an ordinary outlet, the ordinary outlet is connected to GFCI’s load terminal. In this case, the ordinary outlet connected to the load terminals of GFCI and the GFCI itself are protected earth and ground leakage current.
Wiring a GFCI Outlet with Combo Switch
In this formation, the SPST (single way) switch, the combo (switch + outlet), ordinary outlet are connected to the load terminal of GFCI. This means all loads connected to GFCI’s load terminal are protected. One bulb is controlled by the toggle switch in the combo switch outlet, while another is controlled by the single-way switch. In this case, all the loads are protected by the GFCI.
The 3 Types of GFCIs
GFCIs come in three types.
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- The “receptacle-type” GFCI is the most common one and is very similar to the normal wall outlet.
- The second types are the circuit breaker GFCIs, commonly used as replacements for common circuit breakers. The circuit breaker GFCIs offer protection to all receptacles on the circuit.
- The third category are the portable or temporary GFCIs, which are commonly used at construction sites and in homes to protect electric appliances.
How Does a GFCI Outlet work?
The GFCI is connected to the electrical outlet and constantly monitors the current flowing in the circuit. It also records any changes in current flow in real-time.
The GFCI device has three holes – two for neutral and hot wires, and the third one is the ground wire located in the middle of the outlet. The GFCI immediately cuts off power when it detects changes in the flow of electricity.
TIP: GFCI outlets are essential – and required – safety devices for every home. Here’s an article I wrote about why you need to make sure your GFCI outlets are tamper-resistant.
How to Install the GFCI Outlet
You can install a GFCI outlet yourself using DIY instructions or hire a certified electrician to do the job. It is advisable to first acquaint yourself with your home’s electrical system and how it functions. Below are steps to follow when installing a GFCI outlet:
Step 1: Check if Your Circuit is GFCI Protected
Many states in the US have building codes that require homeowners to install GFCI plugs in wet places like baths, laundry rooms, garages, and kitchens. You, therefore, need to finds out first if your home circuit is GFCI protected.
Step 2: Turn Off the Power
Switch off the power at the circuit breaker or fuse to avoid electric shock during installation. Remove the wall plate and use a tester to confirm the power is off.
Step 3: Remove The Old outlet
Remove the existing outlet at the location where you intend to install the GFCI. Pull it out of the circuit box. After removing the existing GFCI, you will find two or more additional wires.
Of the exposed wires, use a tester to identify the one carrying power.
Step 4: Install the GFCI Outlet
The GFCI outlet consists of two wires marked ‘line’ and ‘load.’ The line wire brings in power while load cable distributes the power to other outlets and also offers protection from shock.
The black (power) wire is connected to the line set, while the white one is connected to the load set of the GFCI outlet. Wrap the connections using electrical tape or secure them using a wire nut.
Connect the ground wire to the green screw on the GFCI outlet. Return the GFCI plug into the circuit box and cover it.
Where Should GFCIs Be Used?
GFCIs are mainly used in wet environments to avoid electrical shock and damage to appliances. They are installed in kitchens, bathrooms, laundry, and other areas where electricity may come into contact with water.
Why You Should Install GFCI Outlet
The National Electric Code requires homeowners to install GFCI in their buildings, especially in wet or damp areas. Below are reasons why a GFCI outlet is important:
- Prevent Electric Shock
GFCIs are used to monitor current flow in the electrical circuit. The device has sensors in its inside that detect even the slightest changes in electricity. It also monitors any power flowing along a wrong path.
If an appliance or any electrical device connected to the GFCI comes into contact with water, the GFCI immediately shuts off the power. GFCIs are ideal for protecting your home because they can detect even the smallest changes in current flow.
- Prevent Electrical Fires
Short-circuiting can ignite a fire that can burn down the entire home. Having a GFCI prevents these fires as the device shuts down the circuit whenever it detects changes in current flow.
REMEMBER: As your home ages, the wiring in the home becomes worn out, and the insulation begins to deteriorate. The damaged insulation exposes live wires that can cause a fire if they come into contact.
- Protect Electrical Devices
Short circuits and electricity leaks can cause damage to your electric devices and appliances. You can connect a GFCI to transfer power from the source to the appliance and back to the GFCI again.
The GFCI trips itself if it notices even the smallest changes and cuts off power supply to the device. Consistent electricity leaks can damage devices and shorten their life expectancy.
Precautions When Installing GFCI outlets
Like any other installation that involves handling electricity, you need to be careful when installing GFCI outlets. Below are precautions to look out for during GFCI installation:
- Before doing any wiring, ensure you switch off power from the main supply
- Use switches with the right voltage and ampere rating. Also, use the right sizes of the wires according to the load rating.
- Make sure you apply the correct polarity by verifying the Line and Load terminals. Ensure you connect the wires to the correct sides.
- Portable GFCIs need to be tested well before being used in any operation.
- When hiring a contractor, ensure you go for qualified, authorized, and licensed electricians to ensure correct wiring.
General Rules When Using
- Only one GFCI is used per circuit. Increasing the number may cause the circuit to trip.
- GFCI outlets are installed to protect additional outlets and switches, while the GFCI circuit breaker protects the whole circuit
- You don’t need to install an additional GFCI if you already have the GFCI circuit breaker.
- The GFCI must be well grounded to avoid tripping
Can I Use DIY for GFCI Installation?
Handling electricity requires some level of technical experience due to the fatal nature of even the smallest mistake. While it is possible to install a GFCI yourself using simple tools like pliers and tester, it is recommended to use an electrician who is able to install the device safely without the risk of electric shock.
GFCI are some of the most common devices in your circuit. They are used in areas with water to prevent electric shock and damage to appliances. GFCI Outlets can be wired on both light switches and ordinary outlets.