The most common shock-related, nonfatal injury is a burn. Burns caused by electricity may be of three types: electrical burns, arc burns, and thermal contact burns. Electrical burns can result when a person touches electrical wiring or equipment that is used or maintained improperly. Typically, such burns occur on the hands. Electrical burns are one of the most serious injuries you can receive. They need to be given immediate attention. Additionally, clothing may catch fire and a thermal burn may result from the heat of the fire.
Arc-blasts occur when powerful, high-amperage currents arc through the air. Arcing is the luminous electrical discharge that occurs when high voltage exists across a gap between conductors and current travels through the air. This situation is often caused by equipment failure due to abuse or fatigue. Temperatures as high as 35,000°F have been reached in arc-blasts.
There are three primary hazards associated with an arc-blast.
Five technicians were performing preventative maintenance on the electrical system of a railroad maintenance facility. One of the technicians was assigned to clean the lower compartment of an electrical cabinet using cleaning fluid in an aerosol can. But, he began to clean the upper compartment as well. The upper compartment was filled with live circuitry.
When the cleaning spray contacted the live circuitry, a conductive path for the current was created. The current passed through the stream of fluid into the technicians arm, and across his chest. The current created a loud explosion.
Co-workers found the victim with his clothes on fire. One worker put the fire out with an extinguisher, and another pulled the victim away from the compartment with a plastic vacuum cleaner hose. The paramedics responded in 5 minutes. Although the victim survived the shock, he died 24 hours later of burns.
This death could have been prevented if the following precautions had been taken:
Electricity is one of the most common causes of fires and thermal burns in homes and workplaces. Defective or misused electrical equipment is a major cause of electrical fires. If there is a small electrical fire, be sure to use only a Class C or multipurpose (ABC) fire extinguisher, or you might make the problem worse. All fire extinguishers are marked with letter(s) that tell you the kinds of fires they can put out. Some extinguishers contain symbols, too.
The letters and symbols are explained below (including suggestions on how to remember them):
|A (think: Ashes) = paper, wood, etc.|
|B (think: Barrel) = flammable liquids|
|C (think: Circuits) = electrical fires|
Do not try to put out fires unless you have received proper training. If you are not trained, the best thing you can do is evacuate the area and call for help.
Thermal burns may result if an explosion occurs when electricity ignites an explosive mixture of material in the air. This ignition can result from the buildup of combustible vapors, gasses, or dusts. Occupational Safety and Health Administration (OSHA) standards, the NEC, and other safety standards give precise safety requirements for the operation of electrical systems and equipment in such dangerous areas. Ignition can also be caused by overheated conductors or equipment, or by normal arcing at switch contacts or in circuit breakers.
A 29-year-old male maintenance worker was found at 3:45 a.m. lying on his back and convulsing. Beside him were an overturned cart and an electrical welding machine, both lying in a pool of water on the concrete floor. Arcing was visible between the welding machine and the floor. The worker was transported to the closest hospital, where he was pronounced dead.
An examination of the welding machine showed that there were exposed conductors in the machine’s cables. There were numerous cuts and scrapes in the cables’ insulation. On other parts of the machine, insulation was damaged or missing. Also, the machine did not have a ground connection.
Investigators concluded that the maintenance worker was electrocuted when he tried to turn off the welding machine, which was sitting on the cart. The metal frame of the machine had become energized due to the damaged insulation. When he touched the energized frame, he completed the conducting path to the ground. The current traveled through his body to the ground. Since he was probably standing in water, the risk of ground fault was even greater.
You must take steps to decrease such hazards in your workplace:
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