What Is Arc Flash?

Welder with protective mask.

Across industries, worker safety should take precedence in day-to-day operations. This is especially true for industries, such as the construction, electrical, and manufacturing fields whose daily activities involve the risk of workers being exposed to serious hazards. Arc flash, or arc fault, is one such risk that can cause extreme harm to workers if exposed. Within the electrical industry, workers often come into contact with live circuits and high voltages, putting them at risk of electrocution and electrical burns, from conditions such as arc flash. Implementing strong electrical safety practices and guidelines are essential to protecting workers against such risks.

An arc flash is a kind of electrical explosion or arc fault, often distinguished by a few key qualities, including the high amounts of force and energy it exerts, and its intense temperature and brightness. These types of explosions occur when there are low-impedance connections from the air to the ground or when a certain voltage phase exists in an electrical system. During an arc flash, the electrical current leaves the path and moves to the ground, or from one conductor to another, through the air. This type of explosion can happen as a result of common workplace mistakes and issues, such as equipment failure, dirt and dust, fallen tools, accidental touching, condensation, faulty installation, weathering, and corrosion.

When the explosion occurs, it is usually very sudden and violent and, the resulting damage it causes can be incredibly expensive in terms of repairs and losses. Arc faults are especially dangerous because they can continue to develop, gradually rising in temperature until they damage an entire electrical system either by melting it, dissolving it, or causing trips in the circuit.

Effects Of Arc Flashes

Arc flashes can have effects that are extremely detrimental to the functioning of an electrical system. They result in extreme heat, with temperatures surging upward, sometimes to thousands of degrees Fahrenheit. They usually involve explosions of molten metal and plasma and create vaporizing conditions that can harm buildings, equipment, and people.  Most seriously, arc flashes often result in fires and electrical burns, which can seriously injure not only employees, but bystanders as well. Injuries related to arc flashes can be wide-ranging, but also include permanent nerve and vision damage.

There are several types of equipment currently available that can protect workers against possible arc flash. Most notably, flame resistant clothing can be an excellent tool in protecting workers against possible flames and burns. Flame resistant face shields, hat, helmets, gloves, and shoes are also methods for preventing injury from arc flash.

Reducing Arc Flash

There are several ways that employers can help to reduce the risk of arc flash, as well. These efforts include conducting a hazard analysis to determine the amount of energy a potential arc flash could release throughout the system. Employers should also clearly mark areas in the workplace that are at risk for potential arc flashes, so workers are aware of them. Facilities that use non-current limiting breakers can reduce the amount of available fault current to help lower the amount of energy that could be released by an arc flash. Smaller arc flashes can also be created by shortening the clearing time of the arcs themselves. In addition, employers should ensure that they have in place strong electrical safety guidelines and that they are implemented daily.

Employers can further reduce risk by adopting remote operations, such as remote monitoring, control, and diagnostics software or remote tracking devices. These kinds of equipment allow employees to conduct their normal operations, but at a distance from the presence of potential arc flash, creating greater safety for them. Employers can also reduce risk to better anticipate the conditions under which arc faults occur and to avoid them. For example, monitoring the pressure joints and insulation integrity and using infrared windows can help to prevent conditions from developing that would cause an arc flash to occur. Arc resistant switchgear can also be a viable option as it helps to redirect the energy produced by an arc flash away from the person working.

Arc flash can be a very serious threat to employees working within electrical settings, as it can severely damage equipment and facilities. It can also cause bodily injuries, and even death, to workers. However, with the use of proper electrical safety rules, flame-resistant clothing, and preventative measures, employers can significantly reduce the risk of arc flash exposure to their workers and equipment.

 

References:

  1. http://www.paulsonmfg.com/products/arcflash
  2. http://www.safetyandhealthmagazine.com/articles/12001-avoiding-arc-flash
  3. http://www.public.navy.mil/NAVSAFECEN/Documents/OSH/training/arc_flash_handout.pdf
  4. http://arcadvisor.com/faq/what-is-arc-flash

 

Image Credit: Vladimir Gjorgiev/Shutterstock.com

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