Protect every temporary outlet on site with a GFCI, keep well clear of overhead power lines, which is 10 feet for general equipment and 20 feet for a crane, lock out and tag out anything energized before you service it, and bin damaged cords instead of taping them. Electrocution is one of OSHA's Focus Four killers, and most electrical deaths on site come from three things: contact with overhead lines, faulty tools and cords, and working on equipment that was supposed to be dead but was not. The rules live in 29 CFR 1926 Subpart K. This is federal OSHA in 2026, and some states require more.
GFCI on temporary power
Construction sites run on temporary power, and temporary power is where a lot of shocks happen. OSHA gives you two ways to comply under 1926.404(b)(1):
- Ground-fault circuit interrupters (GFCIs) on all 120-volt, single-phase, 15-, 20-, and 30-amp receptacle outlets that are not part of the permanent wiring. A GFCI cuts the power in a fraction of a second when it senses current leaking to ground, which is what saves you. This is the option most contractors use because it is simple and reliable.
- An assured equipment grounding conductor program (AEGCP), a documented system of regular cord and tool inspections and testing. It is more paperwork and easy to let slip, so GFCIs are usually the safer choice.
Use GFCIs even where you are not sure they are required. They are cheap and they work.
Cords, tools, and grounding
- No damaged cords. Cuts, exposed conductors, a missing ground pin, taped-over splits. A damaged cord gets replaced, not repaired with tape. This is one of the most common and most preventable causes of shock.
- Grounded or double-insulated tools only. Never defeat the ground pin to make a plug fit.
- Keep cords out of water and out of traffic where they get crushed and cut.
- Right cord for the load. An undersized extension cord overheats.
Overhead and underground lines
- 10 feet for general equipment. 20 feet for a crane. Under 1926.600(a)(6), equipment, ladders and materials stay at least 10 feet from a line rated 50 kV or below, plus 0.4 inch for every kV above 50. Cranes and derricks are a different rule and a bigger number: 1926.1408(a)(2) makes 20 feet the trigger, and if any part of the machine, the load line or the load could come within 20 feet at maximum working radius, then the utility de-energizes and grounds the line, or you hold 20 feet with the required encroachment precautions, or you work to Table A for that voltage. 1926.1407(a) says the same for assembly and dismantling. Scaffolds have their own two tables at 1926.451(f)(6), where 10 feet is the figure for everything except an insulated line under 300 volts. Assume every line is live. Cranes, dump beds and scaffold poles contacting lines kill workers every year, which is precisely why the crane number is the larger one.
- Call 811 before you dig. Have underground utilities located and marked before you break ground, and it is free. Hitting a buried line is both an electrocution and an explosion risk.
Lockout, tagout, and working de-energized
The safest energized circuit is a de-energized one. Before you service or repair equipment, the rule is to de-energize it, lock it out, and tag it so no one can switch it back on while you are in it. In construction, the requirements for tagging and controlling circuits sit in Subpart K (1926.417), and they matter most for anyone working on machinery, panels, or wiring.
The principle is simple: the person doing the work controls the lock, verifies the circuit is actually dead with a meter before touching it, and no one else removes that lock. "I thought someone turned it off" is a line that ends careers and lives. If a circuit genuinely cannot be de-energized, that is qualified-electrician work with proper protective equipment, not something to improvise.
Common questions
Do I need a GFCI on a construction site?
Yes. Federal OSHA requires GFCI protection on temporary 120-volt, 15-, 20-, and 30-amp receptacle outlets on construction sites, or an assured equipment grounding conductor program instead. Most contractors use GFCIs because they are simple and cut the power in a fraction of a second when current leaks to ground. Use them even where you are unsure they are required.
How far do I have to stay from overhead power lines?
Ten feet for general equipment and materials, but 20 feet if it is a crane or derrick. Under 1926.600(a)(6) the minimum is 10 feet from a line rated 50 kV or below, plus 0.4 inch for every kV above that. Under 1926.1408(a)(2) a crane triggers at 20 feet, and the employer must then de-energize and ground the line, hold 20 feet with the encroachment precautions, or work to Table A for that line's voltage. Assume every overhead line is live and energized. If you cannot keep the clearance, the utility has to de-energize, insulate, or move the line before work goes ahead.
Can I fix a damaged extension cord with tape?
No. A cord with cuts, exposed conductors, or a missing ground pin has to be taken out of service and replaced, not taped. Taped-over damage is one of the most common causes of shock on site because the tape fails and the fault is still there. Damaged cords and tools get tagged and removed, not repaired on the fly.
What is lockout/tagout and when do I need it?
Lockout/tagout means de-energizing equipment, locking the power off, and tagging it so no one can switch it back on while you work on it. You need it any time you service, clean, or repair equipment that could start up or shock you. The person doing the work holds the lock, verifies the circuit is actually dead with a meter, and no one else removes it.
Do I have to call 811 before digging?
Yes, and it is free. Call 811 to have underground utilities located and marked before you break ground. Hitting a buried power line is both an electrocution and, with gas, an explosion risk. Wait for the utilities to be marked before you dig, and dig carefully near the marks.
The honest bit
- The GFCI requirement, the 10-foot overhead clearance, and the lockout/tagout principles here are federal OSHA in 2026 under 29 CFR 1926 Subpart K. Verify current standards at osha.gov.
- About 22 states run their own OSHA program and can require more. See Working in Your State.
- Work on energized circuits and anything beyond basic tool and cord safety is qualified-electrician work. This is general guidance, not training, and not a substitute for a licensed electrician where the code requires one.
Know someone who needs this?
Keep reading
Templates you might need
Sources
- 29 CFR 1926.404 - Wiring design and protection · GFCI protection and the assured equipment grounding conductor program on construction sites
- 29 CFR 1926.1408 - Power line safety (up to 350 kV), equipment operations · The 20-foot trigger for a crane or derrick operating near a power line, and the three options once it is triggered: de-energize and ground, 20-foot clearance with encroachment precautions, or Table A clearance for the line's voltage
- 29 CFR 1926.600 - Equipment (general requirements) · The general equipment clearance at 1926.600(a)(6): 10 feet for lines rated 50 kV or below, plus 0.4 inch for each 1 kV over 50
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