Article and photos by Greg Havel
Since
our earliest firefighter training, we have been warned about the dangers of electrocution. We have been taught to avoid touching overhead wires with ladders and to confirm that electric power is disconnected before beginning large-scale interior operations.
Additional hazards are present in buildings that are under construction or undergoing remodeling or maintenance, as well as at fire and rescue incidents that involve electricity. The requirements in National Fire Protection Association (NFPA) 70, National Electrical Code, Article 590, are intended to protect workers on the project and in the area, and are enforced by the Occupational Safety and Health Administration (OSHA) under the electrical standards for construction (sub-part K of 29 CFR 1926.400-499, especially under 1926.404(b)(1)) as well as under the “General Duty Clause.” The National Electrical Code is also enforced in most states as part of the building and safety code.
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When we respond to incidents at construction, remodeling, or maintenance job sites, we should expect to find:
- Temporary wiring that meets or exceeds the requirements of Article 590 of the National Electrical Code.
- Temporary lights connected to circuits that are separate from those used for power tools and other electrical equipment.
-
Ground-Fault Circuit Interrupter (GFCI) protection for all temporary electrical receptacle circuits rated for 15, 20, and 30 amperes at 120 volts single-phase, which will be used for power tools and other electrical equipment; including those supplied by generators. Photo 1 shows an electrical receptacle that incorporates GFCI protection. Photo 2 shows a circuit breaker in a panel that incorporates GFCI protection for its circuit. (Note that the GFCI circuit breaker has a different profile than its neighbors; and that it has a “Reset” button.)
- GFCI protection for all permanently wired circuits rated for 15, 20, and 30 amperes at 120 volts single-phase, which will be used for power tools and other electrical equipment (photos 1 and 2). Photo 3 shows a UL-listed cord set (“pigtail”) that includes a GFCI protector in the male plug, which is used where the permanent wiring does not already include GFCI protection.
If we need to use the contractor’s temporary receptacle circuits, for our own protection we must use them “as is
,” without bypassing the GFCIs. We must remember to test each GFCI before using it. This is a quick and simple procedure:
- Press the “Test” button on the GFCI receptacle. The GFCI should trip, usually with a “click,” and the “Reset” button will pop out; or
- Turn off the GFCI circuit breaker. The GFCI should trip, and the “Reset” button will pop out. Then
- Press the “Reset” button (after turning on the GFCI circuit breaker), which should lock back in, and electrical power should be restored.
- If the GFCI will not reset, it is defective and another protected circuit should be used.
If the extension cord or power tool that we plug in causes the GFCI to trip, it is an indication that there is a potential defect in our cord or power tool that can cause injury or fatality, and suggests that we need to remove the cord or tool from service immediately and send it to be inspected and repaired.
We cannot afford to view tripping GFCIs as defective or as a nuisance, whether at a construction site,
an incident, or the fire station. Today’s GFCIs are designed so that they cannot be reset if they are defective. If the GFCI trips, there is a reason for it: electrical current is leaking from the energized conductor or power tool parts, causing an imbalance that is sensed by the GFCI, causing it to trip.
The most common cause of tripping GFCIs on construction job sites and on the fireground is moisture. This can be found in tools operated under wet conditions, and in cords and plugs that have been immersed in water. This results in water wicking back into the fiber packing between the insulated conductors and the cord jacket, reducing the resistance of the insulation and allowing a current leak.
Article 590 of the
National Electrical Code also requires employees who use electrical equipment, power tools, and extension cords to inspect them daily before use. This inspection includes looking for damage of any
kind, missing or broken grounding conductors on plugs, and missing parts. Any electrical equipment found to be defective must be removed from service immediately, tagged, and sent for repair.
Since emergency services are time critical,
the best time to perform this before-use inspection is during our preshift equipment inspection, and as we are picking up equipment and reconditioning it after use at an incident.
GFCI manufacturers state that each GFCI must be tested monthly to ensure that they are working properly. On construction job sites, this test is to be performed and documented weekly. Fire and rescue service personnel should check their GFCIs during each routine equipment check, and while reconditioning equipment after use.
The reason for periodic testing of GFCIs is simple: Some older GFCIs could fail and still function as an ordinary unprotected electrical receptacle. Although today’s GFCIs are designed so that they should not conduct electricity when tripped or after failure, they are still mechanical devices and could still conduct after failure. Pressing the test button on the GFCI will cause it to trip and shut off the electricity. Pressing the reset button will restore the function of the GFCI. Whether the GFCI is new or old, if the GFCI has failed, pressing the reset button will not reset it and should not restore electrical power.
Gregory Havel is a member of the Town of Burlington (WI) Fire Department; retired as deputy chief and training officer; and is a 30-year veteran of the fire service. He is a Wisconsin-certified fire instructor II and fire officer II, an adjunct instructor in fire service programs at Gateway Technical College, and safety director for Scherrer Construction Co., Inc. Havel has a bachelor’s degree from St. Norbert College; has more than 30 years of experience in facilities management and building construction; and has presented classes at FDIC.
Subjects: Building construction for firefighters
