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By W. Jon Wallace, CSP, MBA
Electricity is an integral part of our life, both at home and on the job. Some employees work with electricity directly, as is the case with electricians, engineers, or people employed by electric power utility companies. Other employees, such as office workers, work with electricity indirectly. As a source of power, electricity is oftentimes taken for granted.
Electricity is truly a great invention, however, its misuse can result in tragic loss of life and significant property damage. According to OSHA, approximately 350 electrical-related workplace fatalities occur annually. Electricity should not be feared, but it must be respected. Employees must be protected from electrocution hazards due to:
In this article, we will review common electrical installation violations of OSHA 29 CFR 1910 (Standards for General Industry) Subpart S—Electrical. It is important to note that OSHA’s electrical installation requirements are derived from the National Electrical Code®. This article discusses common industrial electrical installation violations:
OSHA 29 CFR 1910.303 (b)(2) requires all electrical equipment to be used or installed in accordance with any instructions included in the listing or labeling. Common violations include consumer rated coffee makers and box fans being used in a commercial (industrial) work environment. Consumer rated products are normally not grounded and are not intended for continuous operation. The hazard is very real—use of consumer rated products in industrial settings has been responsible for numerous fires. Another violation is using electrical receptacles designed for indoor use in an outdoor environment. In this example, a receptacle designed for wet locations is required. The picture above depicts a consumer rated fan being used in a commercial environment—a violation.
Unguarded energized conductors pose a serious electrocution hazard. OSHA 1910.303 (g)(2)(i) requires all energized conductors > 50 volts within eight (8’) feet of the floor or working surface to be guarded against accidental contact. Typical violations include exposed electrical wiring, unguarded receptacles, and unguarded fluorescent lighting. An example of a serious electrical hazard in shown in the photograph at right. A circuit breaker was removed from a circuit breaker panel but the opening was not covered—exposing employees to a potential electrocution hazard.
This condition occurs whenever the hot and neutral electrical wires are reversed. If an internal fault occurs in the wiring of a piece of equipment, such as a drill or saw, the equipment would start as soon as an employee plugs the power cord into the improperly wired receptacle. Also, equipment will not stop when the power switch is released. OSHA 1910.304 (a)(2) prohibits reverse polarity. A receptacle tester may be utilized to verify that receptacles are wired correctly.
Grounding is designed to protect people from electrocution and it helps prevent electrical fires. If wiring inside a piece of energized equipment, such as a refrigerator, becomes loose and contacts the metal frame, the metal frame becomes energized. This poses a significant electrocution hazard if anyone touches the refrigerator. With a grounded refrigerator, however, this electricity is safely diverted away from the metal frame to earth.
An additional benefit of grounding is that is protects equipment from electrical fires. For instance, the 1980 MGM Grand fire in Las Vegas that resulted in 85 fatalities was the result of an ungrounded deli machine.
Refrigerators, freezers, air conditioners, clothes washing/drying equipment, motors, and tools used in wet and conductive locations are some examples of equipment that must be grounded. Refer to 29 CFR 1910.304 (f) for specific grounding requirements.
An alternative to grounding for portable hand tools is double insulation. A double insulated tool has additional insulation—if the electrical unit does short out, the operator is protected from shock by a double-insulated housing. As a result, double-insulated tools do not require three-wire grounding cords.
Flexible electrical cords, such as extension cords, are designed for temporary—not permanent use. 29 CFR 1910.305(g) addresses flexible cords and cables. Flexible cords and cables may not be used:
Shown at right are two photographs of electrical installations with numerous electrical violations.
Portable electric tools are common in the workplace. These tools are commonly powered with extension cords. Extension cords are more susceptible to damage than fixed wiring. If an employee is using a damaged extension cord in a wet environment a ground fault condition may occur creating a significant electrocution hazard to the employee.
To protect employees against ground fault hazards while utilizing extension cords, a ground fault circuit interrupter (GFCI) should be utilized. A GFCI functions by measuring the outgoing amperage to a piece of equipment and comparing it against the return amperage. If a difference (leak) of > 5 milliamps occurs, the GFCI stops the flow of electricity to protect the equipment user from potential electrocution. OSHA’s Construction Standards (29 CFR 1926) requires ground fault protection on construction sites. 29 CFR OSHA 1926.404 (b) requires ground fault circuit interrupters or an assured equipment grounding conductor program on all construction sites with temporary wiring that contain 120-volt, single-phase 15 and 20 ampere receptacles. As a best practice, GFCI protection should always be utilized when using extension cords in wet or damp environments.
GFCI’s are available as follows:
Correct electrical installation practices are critical to ensure employee safety and also to maintain equipment integrity. It is imperative that all electrical installations meet or exceed all applicable OSHA regulations as well as recognized consensus codes. The following references may be utilized to determine electrical installation requirements:
If you have any questions concerning this article or other safety issues, please contact W. Jon Wallace, "The Safety Guru", at 919.933.5548 or by