Many occasions call for the use of temporary power — post-disaster recovery, extreme weather events, construction work and more. Regardless of what the purpose of a temporary power system may be, most of these installations will depend on the use of portable generators as the central source of energy.
That’s why every electrician should be ready to deploy portable generators as the core of a temporary power system. But what’s safe for a system wired to the central power grid may not be safe for a high-voltage generator (and vice versa). Temporary power systems present their own hazards and, consequently, their own safety guidelines that can reduce the risk for installation and maintenance teams.
Here are a few things electrical workers should keep in mind when using portable generators to create temporary power installations:
- Temporary power systems must comply fully with the National Electrical Code (NEC). Just like permanent electrical wiring, temporary power is governed by the NEC. Article 590 of that code provides safety rules specifically for temporary installations. Be sure to familiarize yourself with Article 590 before installing a temporary power system. Remember that for certain uses, such as temporary holiday light displays, the NEC places a 90-day limit on use of the power system.
- Portable generators should never be used indoors. These gas-burning machines use internal combustion engines to turn an alternator, thus generating electricity. Generators produce carbon monoxide as a byproduct, similar to a car’s engine. This odorless, colorless gas will poison bystanders if it’s allowed to accumulate in any meaningful concentration. This is why it’s crucial to avoid placing generators in any enclosed space, even one that’s ventilated by open windows and doors. The Occupational Safety and Health Administration (OSHA) recommends a minimum of three feet clearance on all sides of a generator, including above the unit, for optimal ventilation.
. The intense heat these engines generate can ignite spilled fuel on contact. Avoid this fire risk by turning off generators and giving them adequate time to cool completely before adding fuel. Refuel generators only when they’re shut off and cool to the touch
- Use ground-fault circuit interrupter (GFCI) outlets. Reduce the risk and severity of electrical shock by employing GFCIs, which are designed to trip and cut power in the event of an unsafe energy path. The NEC requires GFCI protection on all receptacle outlets rated 125-volt, 125/250-volt, single-phase, and 15-, 20- or 30-ampere.
- Use extension cords safely. This means grounded, insulated, outdoor-rated cords with wire sized for the appropriate current load. Remember that longer extension cords reduce voltage, boosting the current; when the conductors aren’t large enough to handle this current, they can overheat. Similarly, don’t connect multiple extension cords to achieve the desired length.
These connections can cause overloads, overheating and even fire.
Please keep in mind that this list is far from exhaustive. Consult the NEC and OSHA standards 1910 Subpart S (for general industry) or 1926 Subpart K (for construction) for full details on working safely with temporary power systems.