08 Jul The GFCI At Work And Home

GFCI Safety at Work and Home

A Ground-Fault Circuit Interrupter (GFCI) is an electrical safety device designed to protect people from serious electric shock caused by ground faults. GFCIs are especially important on construction sites and in wet or damp locations where the risk of electrical shock is increased.

A GFCI continuously monitors the current flowing through an electrical circuit. If it detects a difference between the current leaving and returning through the circuit—indicating that electricity may be flowing through an unintended path—it quickly interrupts the circuit.

Guide for Discussion

How a GFCI Works

A GFCI compares the electrical current traveling to equipment with the current returning from it. If a small imbalance occurs, typically approximately 5 milliamperes, the GFCI trips rapidly and disconnects the power.

For example, if damaged equipment allows electrical current to travel through a worker to ground, a properly functioning GFCI can interrupt the circuit before the exposure results in a more serious electrical injury.

A GFCI is designed to protect people from ground-fault shock hazards. It is different from a conventional circuit breaker or fuse, which primarily protects wiring and equipment from excessive current.

What a GFCI Does—and Does Not—Do

A GFCI provides important protection, but it does not eliminate every electrical hazard.

A GFCI can:

• Detect small differences between outgoing and returning current.
• Interrupt power when current is leaking to ground.
• Reduce the likelihood of serious injury from certain ground-fault exposures.

A GFCI cannot:

• Protect against every type of electrical contact.
• Prevent shock when a person simultaneously contacts two energized conductors and the current remains within the monitored circuit path.
• Make damaged tools, cords, or equipment safe to use.
• Replace proper grounding, insulation, equipment maintenance, or safe electrical work practices.

Never rely on a GFCI as permission to use damaged or improperly maintained electrical equipment.

GFCIs on Construction Sites

For construction work, OSHA requires GFCI protection for 120-volt, single-phase, 15- and 20-ampere receptacle outlets that are not part of the permanent wiring of the building or structure and that are being used by employees.

This commonly includes receptacles supplying:

• Portable electric tools
• Extension cords
• Temporary power systems
• Portable lighting and equipment
• Other cord-and-plug-connected equipment

Where permitted by OSHA requirements, an Assured Equipment Grounding Conductor Program (AEGCP) may be used as an alternative for applicable receptacles. An AEGCP requires a written program, designated competent persons, inspections, testing, and documentation. It is more than simply checking a cord for continuity.

Wet and Damp Locations

Water significantly increases electrical hazards. GFCI protection is particularly important when electrical equipment is used outdoors or around moisture.

• Keep plugs and receptacles dry.
• Do not handle electrical connections while standing in water.
• Protect temporary electrical connections from rain and other moisture.
• Never use damaged extension cords or electrical tools.
• Use equipment suitable for the environment.
• Stop work if electrical equipment cannot be used safely.

A GFCI provides additional protection, but employees should still avoid using electrical equipment in wet conditions unless the equipment and installation are designed for that environment.

Inspect Before Use

Before using electrical tools, equipment, or extension cords:

• Inspect cords for cuts, cracks, fraying, or damaged insulation.
• Check plugs for missing, loose, or damaged prongs.
• Inspect receptacles and connectors for damage.
• Make sure grounding prongs have not been removed.
• Verify that guards, covers, and strain-relief devices are intact.
• Remove damaged equipment from service and tag it “Do Not Use.”
• Never make temporary repairs with electrical tape when the cord or equipment requires replacement or qualified repair.

Test GFCIs

GFCIs should be tested according to the manufacturer’s instructions.

Most units have TEST and RESET buttons. Testing verifies that the device will trip and disconnect power as intended.

If a GFCI:

• Will not trip when tested,
• Will not reset,
• Trips repeatedly, or
• Shows signs of physical damage,

stop using it and have the condition evaluated. Never bypass a GFCI because it continues to trip. Repeated tripping may indicate a ground fault, damaged equipment, moisture, or another electrical problem.

GFCIs at Home

GFCIs are also important in residential locations where electricity and moisture may be present, including bathrooms, kitchens, garages, basements, laundry areas, outdoors, and other locations specified by applicable electrical codes.

At home:

• Use GFCI-protected receptacles where required.
• Test GFCIs periodically according to manufacturer instructions.
• Replace defective GFCIs.
• Keep electrical appliances away from water.
• Never use damaged cords or appliances.
• Use outdoor electrical equipment and extension cords rated for outdoor use.

Remember

A GFCI is an important last line of protection against certain electrical shock hazards, but it does not replace safe work practices.

Inspect electrical equipment before use, keep cords and connections protected from damage and moisture, use required GFCI protection, and never bypass or defeat an electrical safety device.