What Causes an Electrical Arc Flash?

An arc flash, also known as a flashover, is a type of electrical discharge which can be caused by a fault or short circuit condition which passes through an arc gap in two electrodes. Arc flashes can be an extremely dangerous phenomenon, and they cause serious destruction within the home or workplace. In order to prevent arc flashes from happening it is essential that you understand the reasons why they happen in the first place. This article takes a look at some of the most common causes of arc, flashes and it reveals what steps you can take to minimise the risk of an arc flash in your electrical system.

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Understanding Arc Flashes

When uncontrolled conduction of electrical currents from the ground to phase, phase to neutral, phase to phase occurs, the heat energy created by this fault will cause an intense burst of light known as an arc flash. These arc faults are very dangerous and have been known to cause fatal accidents. Because of the arc fault and the concentration of voltage into one place, an enormous amount of energy is released. One of the most common examples of when an arc flash happens is in an inconsistent light bulb when it burns out. When the filament breaks, a small arc flash will envelope the bulb and create a bright blue flash. Many household light fittings will have a fuse built-in to help prevent a sustained arc flash from happening.

Causes of Arc Flashes

The primary cause of an arc flash is when the test probe of an electrical conductor touches the wrong surface or a slipped tool. This will cause an explosive change in state from solid to vapour which will result in considerable pressure, a sound blast and an arc flash. Other common reasons for arc flashes include breaks gaps or damage to the insulation surrounding the electrical system or dust and corrosion on the surface of the electrical conductors. Another reason is due to equipment failure because of improper installation, substandard parts and even wear and tear to the equipment. Arc flashes can happen on a range of electrical circuits; even 480 volt electrical items have the capacity to court cause an arc flash, although equipment that is over 600 volts has a higher risk as an arc flash hazard.

Arc Flash Injuries

Common injuries caused by arc flashes include burns which are caused by direct exposure to the large amounts of heat which can instantly burn human skin and even set clothing on fire. An arc flash can cause temperatures that are up to four times the temperature of the sun’s surface. This extremely high intensity flash might also cause damage to the eye site. Other issues in court include shock waves which can not electrician’s off their feet concussion, risks from flying debris, and shock hazards. A very large arc flash may even cause damage to hearing because of the sound shock waves that it creates.

Preventing Arc Flashes

Regular maintenance is not only a legal requirement in many states and countries, but it’s also very important for the health and safety of electrical technicians as well as for everyone living inside of the residential property that the electrical system is in. Larger electrical systems such as most power lines that are over 1000 volts will have arc flash prevention systems built to help minimise the risk of this from happening. The same applies to high tension power lines, and engineers must take extra care to ensure that the lines are insulated and not positioned too close together to prevent a discharge forming between the conductors. For these reasons, it’s essential that electrical systems are properly installed and regularly checked in order to make sure that they are safe and functioning correctly. Always follow standard protocols, and ensure frequent electrical checks are made.

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