3.3 Ground-fault protection: GFCI or the assured grounding program
A ground fault is current leaving the circuit through a path it was never meant to take — and on a construction site, that path is often a person. 29 CFR 1926.404(b)(1) is OSHA's answer, and it is unusual in giving employers a genuine choice between two very different programs. Most sites pick one, do half of it, and think they are covered. This chapter is both options in full.
1 The choice, in one sentence
1926.404(b)(1)(i): "The employer shall use either ground fault circuit interrupters as specified in paragraph (b)(1)(ii) of this section or an assured equipment grounding conductor program as specified in paragraph (b)(1)(iii) of this section to protect employees on construction sites."
Either. Not both, not neither, and not "we use double-insulated tools." The two options protect in completely different ways: a GFCI watches for the fault and disconnects; an assured grounding program makes sure the ground path is intact so the fault clears through the conductor instead of the person.
2 Option one: GFCIs
1926.404(b)(1)(ii) is precise about what has to be protected: "All 120-volt, single-phase, 15- and 20-ampere 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 personnel protection."
Read the qualifiers. 120-volt, single-phase, 15- and 20-ampere — the outlets everything plugs into. Not part of the permanent wiring — temporary power, spider boxes, generator outlets. In use by employees — if a crew is plugging into it, it counts, whether or not it was installed for them.
A GFCI compares the current going out on the ungrounded conductor with the current coming back on the grounded conductor. When they differ, some current is leaving by another route, and the device opens the circuit. OSHA's fact sheet on generators puts the practical value in one line: "GFCIs shut off power when an electrical current is detected outside normal paths" (FS-3286).
3 Option two: the assured equipment grounding conductor program
1926.404(b)(1)(iii) requires the employer to establish and implement a program covering all cord sets, receptacles that are not part of the building or structure, and equipment connected by cord and plug that is available for use or used by employees. The paragraph then lists seven minimum requirements, and they are all mandatory.
| Paragraph | Requirement |
|---|---|
| (A) | A written description of the program, including the employer's specific procedures, available at the jobsite for inspection and copying by the Assistant Secretary and any affected employee. |
| (B) | One or more competent persons, as defined in 1926.32(f), designated to implement the program. |
| (C) | Visual inspection of each cord set, attachment cap, plug and receptacle of cord sets, and cord- and plug-connected equipment, before each day's use, for external defects such as deformed or missing pins or insulation damage and for indications of possible internal damage — except cord sets and receptacles that are fixed and not exposed to damage. Damaged or defective equipment may not be used until repaired. |
| (D) | Two tests: all equipment grounding conductors tested for continuity and electrically continuous; each receptacle and attachment cap or plug tested for correct attachment of the equipment grounding conductor to its proper terminal. |
| (E) | Those tests performed before first use, before return to service after repairs, after any incident reasonably suspected of causing damage — the paragraph's own example is a cord set being run over — and at intervals not exceeding 3 months, with 6 months allowed for cord sets and receptacles that are fixed and not exposed to damage. |
| (F) | The employer may not make available or permit the use of equipment that has not met these requirements. |
| (G) | Tests recorded, identifying each receptacle, cord set and piece of equipment that passed and the last date tested or the interval for which it was tested. |
Written program, a named competent person, a daily look, two electrical tests, a three-month cycle, and a record. A box of color-coded tape with no written program and no record is not an assured equipment grounding conductor program; it is the tape from one.
4 Which one a site should actually use
| GFCI | Assured grounding program | |
|---|---|---|
| What it does | Interrupts the fault in a fraction of a second | Keeps the fault-clearing path proven and continuous |
| Ongoing effort | Buy the devices, test them, replace failures | Written program, competent person, daily inspection, quarterly testing, records |
| Fails quietly? | Yes — a GFCI can fail to trip; the test button exists for that reason | Yes — between quarterly tests, damage is caught only by the daily visual inspection |
| Protects against | Line-to-ground faults, including through a person | Faults that can be cleared by the grounding conductor and overcurrent device |
| Does not protect against | Contact across two conductors; overhead line contact | The same, plus any fault where the ground path was fine but the exposure was not |
For most sites the honest answer is GFCIs, because the assured grounding program is a real administrative program with a paper trail, and half of one protects nobody. Nothing stops an employer from doing both, and many do: GFCIs on the outlets, plus a daily look at every cord because it is a good habit regardless of which paragraph you are complying with.
5 The trip nobody wants to hear about
A GFCI that trips has found current going where it should not. The two common responses on a jobsite are to reset it, and — when it trips again — to move the tool to an outlet that is not protected. The second is how a known fault gets handed to the next person.
General industry has a paragraph that says exactly what to do, and its logic applies everywhere: 1910.334(b)(2) prohibits manually reenergizing a circuit that a protective device has opened until it has been determined that the equipment and circuit can be safely energized, and prohibits "the repetitive manual reclosing of circuit breakers or reenergizing circuits through replaced fuses."
6 Grounding, bonding and the third prong
Neither option works if the ground path is broken. 1926.404(f)(6) states the requirement for everything on site: "The path to ground from circuits, equipment, and enclosures shall be permanent and continuous."
In general industry the same idea is written as three prohibitions in 1910.334(a)(3): flexible cords used with grounding-type equipment must contain an equipment grounding conductor; attachment plugs and receptacles may not be connected or altered so as to interrupt continuity of that conductor, and may not be altered to allow the grounding pole of a plug to enter the slots meant for current-carrying conductors; and adapters that interrupt the continuity of the equipment grounding connection may not be used.
That last one is the cheater plug, and it is prohibited by name. OSHA FS-3942 says the same thing to workers directly: "Do not remove ground prongs from cord- and plug-connected equipment or extension cords."
- 1926.404(b)(1)(i) gives two options and requires one of them: GFCIs, or an assured equipment grounding conductor program.
- GFCI coverage is all 120-volt single-phase 15- and 20-ampere receptacles that are not part of the permanent wiring and are in use by employees.
- A GFCI does not protect against contact across two conductors or contact with an overhead line.
- The assured grounding program has seven mandatory elements: written program, competent person, daily visual inspection, two tests, a 3-month cycle (6 for fixed undamaged equipment), a prohibition on untested equipment, and records.
- A trip is information. Find the fault instead of resetting, and never move the tool to an unprotected outlet — the logic of 1910.334(b)(2).
- 1926.404(f)(6): the path to ground is permanent and continuous. Cheater adapters and cut ground prongs are prohibited by 1910.334(a)(3).
Free educational content — not OSHA-authorized training, no certificate or card issued. Follow your employer's program and the standards cited.