GFCI Circuit Protection
A Ground Fault Circuit Interrupter (GFCI) device protects us from receiving an
electric shock from faults in the electrical devices we use.
Because of the potential for shock, GFCI protection is used to protect human life.
Circuit breakers and fuses protect equipment—they will not protect people
How Does it Work ?
A GFCI works by comparing the current on the hot side to the current on the neutral side. If
there's the slightest difference in current (5 milliamps), then there is current leaking out
somewhere, possibly through somebody's body. To protect us in this situation, the device quickly
cuts off the power supply to the leaking device, greatly reducing any possible human tissue
damage from electrical current.
A GFCI can remove electrical power in as little as .025 seconds.
A ground-fault circuit interrupter (GFCI) can help prevent electrocution. If
a person’s body starts to receive a shock, the GFCI senses this and cuts off
the power before serious injury.
Water or wet objects are able to conduct electricity easily and can
connect your body to a ground potential, thus increasing your chances
of receiving a shock from a ground fault.
A ground fault happens whenever electricity escapes the confines of
the wiring in an appliance, light fixture, or power tool and takes a
shortcut to ground. When that shortcut is through a human, the
results can be deadly.
About 200 people in the U.S. alone die of ground faults
each year, accounting for two-thirds of all electrocutions
occurring in homes.
GFCI Circuit Protection
Where should we have GFCI Protection?
GFCI protection should be provided anywhere there is a receptacle installed in an area subject to
moisture, as the presence of moisture greatly increases the danger of accidental shock.
GFCI receptacles are most often found in kitchens, baths, laundry rooms, outside the home and in
the garage where electric power tools might be used.
What types of GFCI Protection is Available
There are several types of GFCIs protective devices available today.
The most often used “GFCI Receptacle”, similar to a common wall outlet, is
the type with which most consumers are familiar.
Circuit breaker GFCIs are often used as replacements for electrical
panel standard circuit breakers and provide GFCI protection to all
receptacles on that individual circuit.
Temporary or “plug-in” GFCIs are frequently used in construction and
in outdoor settings with electric tools, mowers, trimmers, and similar
devices. They should not be used as a permanent alternative to a
regular GFCI.
There are GFCIs that attach to appliance cords, such as this one
found on a hair dryer.
When a GFCI is tripped and the problem has been corrected, the GFCI can be manually reset by
pushing the reset button or resetting the breaker switch.
GFCI Circuit Protection
Benefits of Using GFCI Receptacles
 GFCI receptacles cost less than a GFCI breaker
 Additional receptacles can be protected downstream from a single GFCI receptacle
 Using a GFCI receptacle gives the flexibility of breaking up the protection of the circuit
so one receptacle tripping doesn't take out a bunch of receptacles
 When a power fault happens, power can be restored at the receptacle, instead of at the
electrical panel
 There are many models on the market today, breakers might be hard to find depending
on your electrical panel type
Benefits of Using GFCI Breakers
 Protects all receptacles on the circuit it controls
 May last longer than a GFCI receptacle
Testing GFCI Protection
GFCIs should be tested monthly to ensure they are in working condition.
For a GFCI receptacle, pushing the TEST button should cause the
RESET button to pop up.
Remember to push the RESET button to reestablish power and
protection.
If the reset button will not reset, there could be damaged reset
circuitry or the electrical power to the receptacle remains off.
For a GFCI circuit breaker, pushing the TEST button should cause
the breaker switch to move to the tripped position.
Remember to reset the breaker switch to reestablish power and
protection.
Temporary GFCIs should be tested prior to each use.
Many consumers don’t check their GFCIs to verify they are working. GFCIs
are electronic devices that can be damaged or wear out.
GFCI Circuit Protection
Issues with some GFCI protective circuits
 Some stationary motors, such as a bathroom vent fan or fluorescent lighting fixtures,
may produce enough leakage to cause a GFCI to trip.
 Long circuits with many connections can also cause a GFCI to trip. If possible, keep
GFCI circuits less than 100 feet long.
 Using GFCI receptacles outdoors can be problem due to moisture. Moisture can cause
corrosion with the trip circuitry and ultimately lead to failure. Consider mounting a
GFCI receptacle inside the home that controls standard protected outlets outside.
 One must consider how a receptacle will be used, before protecting all receptacles with
GFCI protection. If a receptacle will be used for refrigerators, freezers, garage door
openers and sump pumps, you might be better suited to utilize standard receptacles. If
a GFCI receptacle was to trip, food inside might spoil. If a sump pump receptacle was
to trip, your basement might fill up with water.
It is not possible to tell if a receptacle is GFCI protected or not by just looking at it. If any
particular receptacle doesn't seem to be providing power, not only should you check the
circuit breakers, but also check any GFCI receptacles with push buttons in the area.
The great thing about GFCIs is that they protect you whether or not your
wiring is grounded.
Other uses for GFCI Protection
 GFCIs can be used to upgrade older two-prong (non-grounded) receptacles. The GFCI
is installed in the electrical box without connecting the ground screw (as there is no
ground wire). A label that says "No Equipment Ground" must be placed on the GFCI
receptacle and all downstream receptacles.
 Owners of older houses can upgrade to GFCI receptacles at those locations or have
GFCI breakers mounted in the main breaker panel.
The most effective shock prevention system for electrical equipment and circuits is
a good equipment grounding conductor run from the electrical panel, through the
wall wiring, to the wall receptacle and connected to all metal equipment.
How does a GFCI differ from an AFCI?
 Arc-fault circuit interrupters (AFCIs) are a recently developed electrical safety device
for homes to provide enhanced protection from fires resulting from unsafe home
wiring conditions.
 AFCIs should not be confused with ground-fault circuit interrupters or GFCIs. While
both AFCIs and GFCIs are important safety devices, they have different functions.
AFCIs are intended to address fire hazards, GFCIs address shock hazards.
As local building authorities may have additional requirements, you should see
your local building authority for the latest requirements.