When and where are ground-fault circuit interrupters (GFCI) needed? This is a frequently asked question from employers in all industries.

OSHA standards include specific requirements as to when these devices must be used, but they will often use the General Duty Clause and refer to consensus standards. As employers we must understand the full requirements for using GFCIs.

So, what exactly is a ground fault? OSHA describes a ground fault as a break in the low-resistance grounding path from a tool or electrical system. The electrical current may then take an alternative path to the ground through the user, resulting in serious injuries or death. The GFCI is a fast-acting circuit breaker designed to detect ground faults and shut off electric power in as little as 1/40 of a second. It works by comparing the amount of current going to and returning from equipment along the circuit conductors. When the amount going differs from the amount returning by approximately 5 milliamperes, the GFCI interrupts the current.

There are several GFCI types: Outlet, circuit breaker, portable, cord-connected, and in-line.

OSHA Construction: 29 Code of Federal Regulations Part 1926.404, Subpart K, contains the requirements for GFCIs for construction sites:

All 120V, single-phase 15A and 20A receptacle outlets on construction sites, which are not a part of the permanent wiring of the building or structure and which are in use by employees, shall have approved ground fault circuit interrupters for personal protection.

OSHA General Industry: 29 Code of Federal Regulations Part 1910.304, Subpart S, contains the requirements for GFCIs for general industry:

Temporary wiring installations that are used during construction-like activities, including certain maintenance, remodeling, or repair activities, involving buildings, structures or equipment. All 125-volt, single-phase, 15-, 20-, and 30-ampere receptacle outlets that are not part of the permanent wiring of the building or structure and that are in use by personnel shall have ground-fault circuit-interrupter protection for personnel.

Receptacles other than 125 volt, single-phase, 15-, 20-, and 30-ampere receptacles that are not part of the permanent wiring of the building or structure and that are in use by personnel shall have ground-fault circuit-interrupter protection for personnel.

OSHA Shipbuilding, Ship Repair, Shipbreaking: 29 Code of Federal Regulations Part 1915:

No specific maritime standards exist; however, several OSHA publications state: In order to ensure the safety of workers, it is recommended that all portable electric hand tools and temporary lighting systems use Ground-Fault Circuit Interrupters.

During ship repairing or shipbuilding operations, it is recommended that GFCIs are used with temporary systems or portable equipment.

The use of consensus standards, such as the NFPA 70E, Electrical Safety in the Workplace or the National Electrical Code along with consulting your local authority having jurisdiction will better explain when GFCI devices are needed.

NFPA 70E 110.4(C)

• Maintenance and Construction

  GFCI protection shall be provided for operating or using cord and plug connected tools related to maintenance and construction activity supplied by 125 volt, 15, 20, or 30 ampere circuits. Where employees operate or use equipment supplied by greater than 125 volt, 15, 20, or 30 ampere circuits either GFCI protection or an assured equipment grounding conductor program shall be implemented.


• Outdoors

  GFCI protection shall be provided when an employee is outdoors and operating or using cord and plug- connected equipment supplied by 125 volt, 15, 20, or 30 ampere circuits. Where employees working outdoors operate or use equipment supplied by greater than 125 volt, 15, 20, or 30 ampere circuits, GFCI protection or an assured equipment grounding conductor program shall be implemented.
  
  

The list below are a few of the National Electric Code (NEC) requirements for GFCI’s protection in all 15A and 20A, 125V receptacles:

• 210.8(A)(2) Residential Dwelling Units
• 210.8(B)(3) Commercial Kitchens
• 210.8(B)(5) Receptacles within 6 feet of the outside edge of a sink
• 210.63 Outlets within 25 ft. of heating, air conditioning, and refrigeration equipment
• 406.3(D)(2), (3) Receptacle Replacement
• 422.51 Cord- and plug-connected vending machines
• 424.44(G) Electric Space Heating Cables
• 511.12 Commercial Garages
• 513.12 Aircraft Hangars
• 517.20(A) Healthcare Facilities
• 525.23 Carnivals, Circuses, and Fairs
• 527.6 Temporary Installations
• 547.5(G) Agricultural Buildings
• 555.19 Marinas and Boatyards
• 590.6 Temporary installations
• 600.10(C)(2) Portable or mobile signs
• 620.23, 620.85 Elevator Pits and Escalators
• 680.22 through .51 Electrical near swimming pools, hot tubs, fountains
• Article 682 Natural and artificially made bodies of water
  
  

GFCIs should be tested periodically to ensure they are working properly. It is recommended to follow manufacturer's instructions regarding the testing of the ground fault circuit interrupter. Contractors should verify proper operation of GFCIs by testing prior to using any device when they are not familiar with the history or any prior testing.

Lastly, when using portable GFCI’s on the downstream side of a receptacle the GFCI must be used as close to the supply receptacle as possible.

Resources

• OSHA Construction eTool – Electrical incidents >>Ground Fault Circuit Interrupters
• OSHA QuickTakes – Ground-Fault Protection on Construction Sites – OSHA 3007, 1998 (Revised)
• OSHA Booklet – Controlling Electrical Hazards – OSHA 3075, 2002 (Revised)
• OSHA Document – Safety Health Injury Prevention Sheets (SHIPS) – Shipboard Electrical
• NFPA 70E Electrical Safety in the workplace (2018 edition). Available only through NFPA.org