fast facts 

Ground-Fault Circuit Interrupters 

Protect You From Electrical Shock Hazards 

December 2009 

Office of Compliance 

advancing safety, health, and workplace rights in the legislative branch 

www.compliance.gov 

Purpose of the GFCI 

A ground-fault circuit interrupter (GFCI) is used to protect people from electrical shock 

hazards caused by malfunctioning electrical appliances. If a person is using a defective 

electrical appliance and also touching a wet surface or very conductive surface, the 

person could become part of the grounding pathway for the fault current. This condition 

can send a dangerous electrical current through the body, causing serious electrical 

shock or death. An electrical current as small as 10 milliamperes (mA) across the chest 

of a person is reported to cause the heart to beat irregularly, possibly resulting in death. 

According to the National Fire Protection Association’s (NFPA) National Electrical 

Code (NEC), a GFCI is “a device intended for the protection of personnel that functions 

to de-energize a circuit or portion thereof within an established period of time when a 

current to ground exceeds the values established for a Class A device.” It is installed in 

electrical outlets or in extension cord circuits which will quickly stop current flow in the 

circuit when the fault current exceeds a range of about 4 mA to 6 mA, as seen in Figure 1. In 

recent years, the Occupational Safety and Health Administration (OSHA) and the National 

 Electrical Code have expanded the applications requiring GFCIs. 

Where are GFCIs Required to be Used? 

OSHA and the NEC now require all bathroom and rooftop outlets to have 

GFCI protection. The NEC currently requires all kitchens, outdoor public 

areas, wet sinks, swimming pools, hot tubs, elevator pits, machinery 

rooms, hospital critical care, electrical life support equipment areas, snow 

melting equipment, and roof-mounted solar photovoltaic systems to have 

GFCI protection in the outlet receptacles for 125 volts single phase 

circuits or power circuits going to this equipment. See Figures 2 and 3 as 

examples of locations now covered under the NEC. 

 

 

Outdoor electrical outlets and those in bathrooms and near kitchen sinks 

are the most common places where GFCIs are found, but GFCIs are protective 

in any wet or damp area where electrically powered tools, devices, or equipment are used. Both OSHA and the NEC require all temporary wiring circuits, like extension cords used on construction 

and similar work sites, to have GFCI protection in each circuit. Many newer extension cords now have built-in or integral 

GFCI protection as shown in Figures 4 and 5. Because building repair, renovation and similar construction type work often 

occurs outdoors, where conditions may be wet or damp, GFCIs provide a good means to protect workers using regular hand

-held electric power tools and lights from electrical shock hazards caused by ground-faults. 

Figure 1 Outlet with GFCI 

protection 

Figure 2 Kitchen outlet not meeting NEC 

GFCI protective requirements 
 

This information does not constitute advice or an official ruling of the Office of Comp liance or the Board of Directors and is intended 

for educational purposes only. For further information or comments concerning this Fast Facts, please refer to the Congressiona l 

Accountability Act (2 U.S.C. 1301 et seq.) and the regulations issu ed by the Board, or you may contact the Office of Compliance , 

202-724-9249.

The Office of Compliance advances safety, 

health, and workplace rights in the U.S. Congress 

and the Legislative Branch. Established as an 

independent agency by the Congressional Accountability Act of 1995, the Office educates employees and employing offices about their rights 

and responsibilities under the Act, provides an 

impartial dispute resolution process, and investigates and remedies violations of the Act. 

If you have any questions, please do not hesitate to 

contact the Office of Compliance: 

Room LA 200, John Adams Building 

110 Second Street, SE 

Washington, D.C. 20540 

t/ 202-724-9250 

tdd/ 202-426-1912 

f/ 202-426-1913 

Peter Ames Eveleth 

General Counsel 

Mary-Margaret Smith 

Editor Download the entire Fast Facts suite at http://www.compliance.gov 

Fast Stats 

 According to the U.S. Department of Labor’s Bureau of Labor Statistics, in 2007, there were 1,480 workplace injuries 

from electrical shock and 1,100 injuries caused by contact with electric current that resulted in burns. 

 The National Fire Protection Association report for 2008 states that electrical fires and electrical failures or malfunctions 

result in an average of 53,600 home fires each year. These fires cause more than 500 deaths, injure 1,400 people, and 

account for $1.4 billion in property damage. 

GFCI Maintenance and Care 

GFCIs need to be maintained in serviceable condition to prevent electrical shock and burn injuries. This means that 

they need to be tested at least annually to make sure they are providing the desired protection using the test button on 

the GFCI. GFCI outlets are typically recognizable by their red and/or black “reset” and “test” buttons as shown in 

Figure 1, or the two buttons shown in Figures 4 and 5. The test button should be used to check to see if the GFCI is 

working properly, as it will cause the red button to pop out when the circuit is opened. The same thing happens when 

an electrical appliance malfunctions with an electrical fault or short circuit current. The GFCI interrupts the circuit and 

stops the current flow to the appliance. When this occurs, you should unplug the appliance, and then press the “reset” 

button. If you try to plug the appliance back in and the GFCI pops again, then you should get the appliance serviced 

and repaired before trying to use it again, or replace it with a properly working unit. If you find a GFCI that does not 

work properly or you see that it has some physical damage, you need to notify your supervisor and the maintenance 

technician so that it can be promptly repaired and returned to service. While the GFCI has increased safety, one should 

never forget the danger that exists when water and electricity come in contact with each other. 

A GFCI is not the sole safety device required on each circuit. There is also a requirement for overcurrent protection 

that is typically accomplished by using a circuit breaker in the panelboard. All circuits must have an effective 

grounding system with low impedance on the ground wire back to the panelboard. 

Figure 3: Bathroom receptacle not meeting 

OSHA and NEC GFCI protection 

 Figure 4: GFCI device for use with an exten- 

 sion cord for temporary service 

Figure 5: GFCI built directly into an extension 

cord for temporary service