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 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:
Electrical Distribution Panels
The Occupational Safety and Health Administration (OSHA) recommends taking the following actions:
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:
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:
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.
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.
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:
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.