Electrical hazards can expose workers to electric shock, burns, fires, and electrocution. Extension cords, portable power tools, temporary wiring, and electrical equipment are common in construction, maintenance, manufacturing, warehouses, shops, and many other workplaces. When equipment is damaged or electrical current finds an unintended path to ground, a worker can become part of that path.
Ground-fault circuit interrupters, commonly called GFCIs, provide an important layer of protection against ground-fault electrical shock. Understanding what GFCIs do, where they are required, and how to use them correctly should be part of workplace electrical safety training.
What Is a GFCI?
According to OSHA, a GFCI is a fast-acting circuit breaker designed to shut off electrical power when a ground fault occurs. A ground fault can happen when electrical current leaves its intended path and takes another path to ground, potentially through a person.
A GFCI continuously compares the amount of current traveling to electrical equipment with the amount returning from it. OSHA explains that when the difference is approximately 5 milliamperes, the GFCI interrupts the circuit. It can shut off power in as little as 1/40 of a second.
This rapid response can significantly reduce the risk of serious injury from a ground fault.
Why GFCI Protection Is Important
Construction sites and other workplaces can be particularly challenging environments for electrical equipment. Extension cords and power tools may be moved frequently and exposed to rough handling, moisture, sharp edges, vehicles, equipment, and other conditions that can damage insulation or wiring.
OSHA notes that normal construction use can result in insulation breaks, short circuits, and exposed wires. Without ground-fault protection, electrical current from damaged equipment may travel through a worker’s body, potentially causing electrical burns, fire, or death.
GFCIs and Wet or Damp Conditions
Water increases the danger associated with electricity because wet conditions can provide a conductive path for electrical current.
GFCI protection is especially important where electrical tools, extension cords, or equipment are used in locations where ground-fault hazards may be present. Workers should also avoid standing in water while using portable electrical tools and should use equipment that is appropriate for the environment.
Never assume that using a GFCI makes it safe to use damaged electrical equipment or work carelessly around water.
OSHA GFCI Requirements for Construction
OSHA Construction Standard 1926.404(b)(1) requires employers to provide ground-fault protection on construction sites through GFCIs or an assured equipment grounding conductor program (AEGCP), as specified by the standard.
OSHA Standard 1926.404(b)(1)(ii) requires approved GFCI protection for personnel on all 120-volt, single-phase, 15- and 20-ampere receptacle outlets on construction sites that are not part of the permanent wiring of the building or structure and are being used by employees, subject to the exceptions in the standard.
Assured Equipment Grounding Conductor Program
OSHA allows an assured equipment grounding conductor program as an alternative method of providing required ground-fault protection in applicable construction situations.
An AEGCP is more than simply inspecting extension cords. It is a formal program that includes a written description, designated competent person, required inspections and electrical tests, and records of those tests.
OSHA GFCI Requirements for General Industry
GFCI requirements also apply to certain general industry installations and work situations.
For example, OSHA’s electrical requirements include GFCI protection for specified receptacles in locations such as bathrooms and rooftops. Separate requirements apply to temporary wiring used during maintenance, remodeling, repair, and similar construction-like activities.
Employers should determine which OSHA electrical requirements apply to the specific workplace, installation, equipment, and work being performed rather than assuming that construction and general industry requirements are identical.
Types of GFCIs
GFCI protection can be provided in several different forms. The appropriate type depends on the electrical installation and work being performed.
GFCI Receptacles
A GFCI receptacle incorporates the protective device directly into the receptacle. These are the familiar outlets with TEST and RESET buttons.
Portable GFCIs
Portable GFCIs can be used where permanent GFCI protection is not incorporated into the receptacle. Depending on the design, a portable unit may plug into an existing receptacle or be incorporated into a portable power distribution device.
Portable GFCIs intended for outdoor environments must be suitable for those conditions. OSHA notes that units exposed to rain must be listed as waterproof.
Cord-Connected GFCIs
A cord-connected GFCI incorporates the GFCI into an attachment plug or cord assembly. These devices can protect the cord and equipment connected to it and typically include TEST and RESET buttons.
Test GFCIs Before Use
A GFCI can only provide protection when it is functioning correctly.
Follow the manufacturer’s recommended testing procedure to verify that the GFCI operates properly. OSHA specifically recommends following manufacturer testing procedures as part of preventing ground-fault incidents.
If a GFCI does not trip or reset as expected, remove it from service and do not rely on it for protection.
Inspect Cords, Tools, and Electrical Equipment
GFCI protection does not eliminate the need to inspect electrical equipment.
Before use, check extension cords, plugs, receptacles, and portable electrical tools for visible damage. Look for conditions such as:
- Frayed, cut, or damaged insulation
- Exposed wires
- Missing or damaged grounding prongs
- Cracked tool housings
- Damaged plugs or receptacles
- Loose connections
- Evidence of excessive wear or other damage
Remove defective electrical equipment from service until it has been properly repaired or replaced. OSHA specifically identifies frayed cords, missing ground prongs, and cracked tool casings as conditions requiring equipment to be removed from use.
When GFCIs Do Not Protect
One of the most important things workers should understand is that a GFCI does not make all electrical work safe.
OSHA specifically warns that GFCIs do not protect workers from line-contact hazards, such as contacting an overhead power line or simultaneously contacting certain energized conductors. GFCIs are designed primarily to protect against ground-fault shock hazards.
Workers must still follow safe electrical work practices, maintain required distances from energized equipment and power lines, inspect tools and cords, use appropriate grounding or double-insulated equipment, and deenergize electrical circuits when required.
OSHA Construction Standard 1926.416(a)(1) requires employees to be protected when working close enough to an electric power circuit that they could contact it during the course of their work.
OSHA General Industry Standard 1910.333(a) similarly requires safety-related work practices to prevent electric shock and other injuries when employees work on or near equipment or circuits that are or may be energized.
GFCI Safety Reminders
GFCIs are an important part of electrical safety, but they should be used together with other safe work practices.
Remember to:
- Use GFCI protection where required.
- Test GFCIs according to the manufacturer’s instructions.
- Inspect extension cords, plugs, tools, and equipment before use.
- Remove damaged electrical equipment from service.
- Keep electrical equipment away from water whenever possible.
- Use equipment that is suitable for the environment.
- Never remove grounding prongs from plugs.
- Do not assume a GFCI makes unsafe electrical equipment safe to use.
- Follow manufacturer instructions and applicable OSHA requirements.
Prevent Ground-Fault Electrical Injuries
Never take electricity for granted. A damaged cord, defective tool, wet environment, or other electrical problem can create a serious hazard with little warning.
GFCIs can interrupt electrical current quickly when a ground fault is detected, providing an important layer of protection for workers. Proper GFCI use, regular equipment inspections, appropriate grounding, and safe electrical work practices work together to help prevent electrical shocks and other serious electrical incidents.
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