Electrical Hazards

​If not used properly, electricity can cause electrical shock and burns to you and your employees. It can also create fires and explosions that destroy property. All electrical installations should be performed by licensed electricians to the standards of the National Electric Code. The following information may help your organization address some common electrical hazards. 

Exposed Wiring

Exposed wiring is one of the most common electrical hazards, and in many cases it is the easiest to correct. Areas to check for exposed wiring include: 
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• Junction boxes without cover plates 
• Extension cords and power cords 
• Electrical boxes with missing knockouts 
• Electric powered machinery 
• Conduit runs that may have been damaged 
• Locations where nonmetallic sheathed cable is used below seven feet 
• Locations where wires have been run outside of conduit 

Electrical Distribution Panels

The Occupational Safety and Health Administration (OSHA) recommends taking the following actions: 
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• All panels should be labeled with the voltage, current and usage
• All control and distribution panels should remain closed at all times and opened only by authorized personnel
• A clear space (of at least three feet) should be maintained around all electrical panels to allow for access in an emergency

Extension Cords

Extension cords are used in almost every organization to temporarily power items such as fans, power tools and lighting fixtures. Consider the following when using extension cords: 
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• Do not run extension cords through holes in walls, ceilings, floors, doorways, windows, roof hatches or other similar openings
• Do not use extension cords as a substitute for permanent wiring; if an extension cord is used to power the same piece of equipment for longer than 30 days, a licensed electrician should install permanent wiring
• Do not conceal extension cords behind building walls, ceilings or floors
• Protect extension cords from damage such as sharp edges and entanglement in machinery; do not leave extension cords on floors where they can be run over by carts
• Do not permanently attach (e.g., staple or nail) extension cords to a building surface 

Inspect all extension, tool and appliance cords on a regular basis for damaged insulation, exposed wiring and damaged plugs. Cords with missing ground prongs should be repaired or replaced as soon as possible to maintain proper grounding.
Additionally, three-prong to two-prong adapters should not be used to connect a three-wire, grounded electrical device to a non-grounded circuit. If you use two-prong extension cords in your facility, they should be removed and replaced with grounded three-prong extension cords as soon as possible. 

Power Strips and Surge Protectors

Power strips and surge protectors are commonly used to provide electricity to multiple pieces of equipment from one electrical outlet. While very handy, these devices can be serious electrical hazards if not used properly. If power strips or surge protectors are present in your facility, follow the guidelines:
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• Only use surge protectors for electronics (e.g., computers, telephones, printers, etc.) as they are not designed to support resistive loads from items such as power tools, fans or lighting fixtures 
• Do not use power strips as a substitute for permanent wiring; if the same device is plugged into the same power strip for more than 30 consecutive days, additional permanent outlets should be installed
• Devices approved only for indoor use should not be used outdoors or in wet or damp interior locations
• Do not "daisy-chain" (i.e., plugging one power strip into the receptacle of another power strip) power strips and surge protectors as overloaded circuits increase the risk of fire

Lockout / Tagout Program

When working with electricity, it is important to understand the principles of a proper lockout/tagout program. Lockout/tagout is a system to prevent the release of energy or operation of machinery or equipment. The system also warns other employees that equipment is being worked on. 

• Lockout—The placement of a device that blocks the flow of energy from a power source to a piece of equipment
• Tagout—The placement of a tag on or near the lockout device to warn others not to restore energy to the equipment

According to OSHA regulations, lockout/tagout should be used whenever an employee is required to remove or bypass a guard or other safety device or is required to place any part of his or her body in the "point of operation" of the machine or where an associated danger zone exists during the machine's operating cycle. Lockout and tagout should always be performed together. While a lockout-only system is generally effective, a tagout-only system does not provide the maximum protection for employees and contractors. 

Basics of Arc flash

Arc flash is a term used to describe an electrical explosion caused by an arcing fault. The electrical explosion results in a thermal, pressure and sound wave that can cause extensive equipment damage, severe injury and death.
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A recent claim involved an arc flash incident on a high school campus. The arc flash occurred at a 100-amp, 480 volt fused disconnect switch during troubleshooting activities. Personnel were injured, the campus lost power for the day and equipment repair costs totaled approximately $140,000. If appropriate safety and maintenance practices had been followed, this incident may have been avoided.

What is an Arcing Fault?

​An arcing fault is caused by the breakdown of insulating material (usually air in low voltage systems) between energized components and the ground. Arc fault current is usually low. Therefore, protective devices, such as fuses and circuit breakers, take a protracted period of time to open to stop the fault. The arcing fault continues until the arc flash occurs.

Electrocution vs. Arc Flash

​Arc flash is not the same as electrocution. Electrocution occurs when a person comes in contact with an energized component. Electrocution can cause significant injuries and death, but typically will not cause extensive equipment damage. Since there is a significant amount of awareness concerning electrocution, people are careful to follow all safety procedures and use safety equipment when around energized equipment. Arc flash is a recently recognized electrical hazard. The National Fire Protection Association (NFPA) 70E, fifth edition, was one of the first standards to specifically address arc flash hazards. It was published in 1995. 

​Industry awareness of arc flash hazards, arc flash mitigation techniques and safety standards are continuing to evolve.

Arc Flash Factors

It is important to recognize that arc flash can happen on low voltage and high voltage systems. The following factors determine the extent of the hazard:

• Amount of energy the power system can deliver
• Time to sense a fault and open a protective device
• Distance a person is from the flash

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These factors should be evaluated in an arc flash study. The results of an arc flash study aid in the establishment of flash protection boundaries, selection of personal protective equipment (PPE) and selection of arc flash hazard labels.

Electrical Self-Inspection Checklist (AIG)
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OSHA - Electrical Safety