23 October, 2014
Arc flash is an explosion of flame, debris, sound and force, typically in electrical switchboards causing thousands of injuries every year, resulting in serious burns and sometimes death.
The extent of the 'flash' is determined by the distance from the arc and the energy available, and is the result of either a phase to phase fault or phase to earth fault or where there is a low impedance path to ground.
The causes of arc flash are numerous and quite varied, however the major causes are due to human error, the absence of any type of preventative maintenance procedures or equipment that has not been designed to prevent arc flash.
When the fault occurs there is a rapid heating of air molecules, combined with the ionisation and vaporisation of metallic elements, before a huge blast of pressure which contains both heat and light energy.
The blast which usually lasts for less than a second can reach extreme temperatures and causes debris from the electrical component as well as molten material to be discharged through the air.
Not only are operators at risk of serious flash burns from the blast or molten material, they could suffer hearing/vision loss, physical trauma and even death. In addition to personal safety, there are significant consequences to a business. Equipment damage, production downtime, repair expenses and damage to the company image for failure to comply with OH&S requirements.
Minimise risk associated with an arc flash:
- Wearing flame resistant apparel
- Enforcement of quality maintenance procedures
- Installation of equipment and controls outside the electrical enclosure, this allows visual inspections of live circuits without opening the unit.
- Consider using FLIR IR Windows