Issues
- Ignoring basic safety measures while using generators poses serious risks, including electrical shock, electrocution, carbon monoxide poisoning, physical burns, and fires.
- A single 15-amp generator line produces 100 times the milliamps needed to cause a fatal accident. Ground-fault circuit interrupters (GFCIs) are an essential safeguard.
- One important safety factor often overlooked is that built-in GFCIs on generators are not a failsafe solution.
- Wet or damp conditions significantly increase the risk of electrical shock and electrocution.
- Incorrect generator setup or improper application of the portable power source and connected tools can eliminate the protection provided by GFCI devices.
- Generator shock hazards and electrocutions typically occur when a portable generator is not bonded or grounded properly or when safety precautions are ignored.
- Carbon monoxide from a generator’s exhaust is a significant hazard in any enclosed area.
Sources of Hazards
- Failure to follow the manufacturer’s safety guidelines.
- Improper use of power or accidentally energizing other electrical systems, causing electrical shock or electrocution.
- Carbon monoxide from a generator’s exhaust.
- Physical burns from improperly refueling a generator or approaching a generator with obvious defects.
- Improperly storing generator fuel too close to an ignition source.
- Noise and vibration hazards.
Causes – Risk Factors
- Operating generators inside enclosed areas presents a risk of carbon monoxide poisoning.
- Refueling generators while they are still hot ignores the required 20-minute cool-down period and creates burn and fire hazards.
- Running generators too close to combustible materials creates burn and fire hazards.
- Failure to provide carbon monoxide monitoring in enclosed areas can result in undetected poisoning until it is too late.
Regulations
Generator Safety
29 CFR 1926.404(b)(1)(i)
The employer shall use either ground-fault circuit interrupters (GFCIs), as specified in paragraph (b)(1)(ii), or an assured equipment grounding conductor program, as specified in paragraph (b)(1)(iii), to protect employees on construction sites. These requirements are in addition to any other requirements for equipment grounding conductors.
29 CFR 1926.404(f)(3)(iii)
Neutral conductor bonding. A neutral conductor shall be bonded to the generator frame if the generator is a component of a separately derived system. No other conductor need be bonded to the generator frame.
29 CFR 1926.404(f)(3)(i)(A)
The generator supplies only equipment mounted on the generator and/or cord-and plug-connected equipment through receptacles mounted on the generator.
29 CFR 1926.404(f)(3)(i)(B)
The non-current-carrying metal parts of equipment and the equipment grounding conductor terminals of the receptacles shall be bonded to the generator frame.
29 CFR 1926.404(f)(4)
For AC premises wiring systems, the identified conductor shall be grounded.
29 CFR 1926.404(f)(5)(i)
For a grounded system, a grounding electrode conductor shall be used to connect both the equipment grounding conductor and the grounded circuit conductor to the grounding electrode. Both conductors shall be connected to the grounded circuit conductor on the supply side of the service disconnecting means or, if the system is separately derived, on the supply side of the system disconnecting means or overcurrent devices.
29 CFR 1926.404(f)(5)(ii)
For an ungrounded service-supplied system, the equipment grounding conductor shall be connected to the grounding electrode conductor at the service equipment. For an ungrounded separately derived system, the equipment grounding conductor shall be connected to the grounding electrode conductor at or ahead of the system disconnecting means or overcurrent devices.
Important Generator Use Information and Rules
Electrical Safety Precautions
- Never attach a generator directly to the electrical system of a structure (home, office, trailer, etc.) unless a qualified electrician has professionally installed the generator with a transfer switch.
- Avoid overloading the generator’s rated capacity. Do not start generators with electrical loads connected.
- Visually inspect the generator before use. Remove defective equipment from service and mark or tag unsafe generators out of service.
- Always use grounded cords and inspect them for damage before use.
- Use the proper cord for the wattage being used.
- Inspect all cords daily and keep them organized to prevent tripping hazards and electrical shock.
- Avoid water exposure. Keep generators dry to prevent electrical shock.
- Always use GFCI protection. Our corporate policy requires 100% GFCI protection.
- Start and stop the generator only when no electrical loads are connected.
- Ensure the generator has 3 to 4 feet of clear space above and on all sides before use.
- Ensure all electrical connections are secured with strain-relief devices.
- Do not lose the grounding or grounding bond. A standalone generator poses a danger if the frame becomes ungrounded. When a frame is isolated from the ground (on a skid, in a trailer, on composite or wood decking, or in a truck), the risk of electrocution is greatly increased because it is no longer grounded.
Use
- Carbon monoxide exposure is a significant hazard. Keep generators at least 20 feet away from employees and never operate them in enclosed spaces.
- Use ground-fault circuit interrupters (GFCIs), especially where electrical equipment is used in wet or damp locations.
- Ensure the generator is properly grounded and all grounding connections are tight. Consult the manufacturer’s instructions for proper grounding methods. NEC 250.52(G).
- Never handle a generator’s electrical components if you are wet or standing in water.
- Turn off and do not use any electrical equipment that emits unusual odors or begins smoking.
- Keep portable generators as far away as possible from work areas and gathering spaces. Wear hearing protection if this is not possible.
- Place generators at least 20 feet from doors, windows, fresh air intakes, and flammable materials. (CDC guidance, April 5, 2024.)
- Never attempt to power a job site or house wiring system by plugging a generator into an outlet (backfeeding). This practice is extremely dangerous and creates an electrocution hazard for workers, utility personnel, and others served by the same utility transformer.
Remember
If the system is not bonded or grounded correctly, or you ignore safety procedures, you might become the best path to ground.
Fire Safety Precautions
- Before fueling or refueling, shut down the generator and allow it to cool for a minimum of 20 minutes.
- Store fuel properly. Keep fuel at least 20 feet away from open flames, sparks, and the generator.
- Monitor generator temperature to prevent overheating.
- Keep a 20-pound ABC fire extinguisher nearby (no more than 75 feet away).
- Generators with plastic gas tanks and unvented plastic gas caps are prohibited on job sites.
What You Need to Know About Generator Use
Important Do’s to Keep in Mind About Generator Use
- Do use generators only as intended and according to the manufacturer’s instructions.
- Do ground your generator as recommended by the manufacturer.
- Do plan for adequate ventilation and consider heat and carbon monoxide from the generator’s exhaust.
- Do allow the generator to cool for a minimum of 20 minutes before refueling.
- Do store generator fuel at least 20 feet away from the generator.
- Do wear hearing protection around operating generators.
- Do inspect the generator for damage or loose fuel lines.
- Do keep the generator dry.
- Do use GFCIs and proper grounding and bonding as required by the manufacturer’s instructions.
- Do inspect all electrical connections. Use heavy-duty, outdoor-rated extension cords with the proper power rating. Avoid overloading the generator by connecting only the tools it is designed to handle. Most portable generators require a 12-gauge outdoor-rated extension cord with GFCI protection.
- Do know your fuel type and storage requirements:
- Gasoline: Store in approved containers under proper storage conditions.
- Diesel: Store in approved containers under proper storage conditions.
- Propane: Store in approved containers under proper storage conditions and understand allowable storage quantities, occupied-space requirements, and tank placement requirements.
- Do provide additional grounding if the generator frame is not in direct contact with the earth.
Important Don’ts to Keep in Mind About Generator Use
- Don’t use generators while standing in water or in wet conditions.
- Don’t approach or use electrical equipment that has unusual odors or begins smoking.
- Don’t ignore clutter or poor housekeeping around the generator.
- Don’t start or stop the generator with electrical loads connected.
- Don’t refuel a hot generator.
- Don’t connect a generator to an existing job site temporary power distribution system.
- Don’t forget the 20-20-20 Rule:
- Place the generator at least 20 feet from doors, windows, enclosed areas, fresh air intakes, and confined spaces.
- Keep the generator at least 20 feet from combustible materials and accelerants.
- Never refuel the generator until it has cooled for at least 20 minutes. (CDC guidance, April 5, 2024.)
- Don’t isolate the generator from the ground by placing it on a skid, in a trailer, on composite or wood decking, or in a truck.
- Don’t overload electrical lines or circuits.
- Don’t overload the generator.
Centers for Disease Control and Prevention. Generator Safety. National Institute for Occupational Safety and Health, 5 Apr. 2024, https://www.cdc.gov/niosh/topics/co/generators.html. Accessed 30 June 2026.
National Fire Protection Association. NFPA 70®: National Electrical Code® (NEC). National Fire Protection Association, https://www.nfpa.org/codes-and-standards. Accessed 30 June 2026.
Occupational Safety and Health Administration. Ground-Fault Protection on Construction Sites. U.S. Department of Labor, https://www.osha.gov/electrical/ground-fault-protection. Accessed 30 June 2026.
Occupational Safety and Health Administration. Portable Generators. U.S. Department of Labor, https://www.osha.gov/portable-generators. Accessed 30 June 2026.
Occupational Safety and Health Administration. 29 CFR 1926.404—Wiring Design and Protection. U.S. Department of Labor, https://www.osha.gov/laws-regs/regulations/standardnumber/1926/1926.404. Accessed 30 June 2026.
Occupational Safety and Health Administration. Construction eTool: Electrical Incidents. U.S. Department of Labor, https://www.osha.gov/etools/construction/electrical-incidents. Accessed 30 June 2026.
