11 Arc Flash Myths, Facts and Folklore
Electricity is a unique hazard in that under normal circumstances, you can’t see it, hear it or smell it yet if you ignore or forget about it, there can be extremely deadly consequences.
Let’s look at what the top 11 facts that should be known about Arc Flash:
Arc Flash is a low frequency, high consequence event which is caused when the electric current flows through the air gap between conductors, or conductors and earth. The explosive release of energy can continue to develop until something in the system either trips, melts or vaporizes and the alarming thing is that this happens within a fraction of a second.
Characteristics of an Arc Flash include: a plasma ball reaching 19,500C, a blast powerful enough to knock you up to ten feet away, noise loud louder than 140 decibels – just like a gun going off next to your ear, molten copper vapour exploding from the blast which can literally copper plate if you’re not properly protected and finally shrapnel and debris showers.
The biggest cause is human error; many people get distracted and touch things they shouldn’t. Or they switch off the cubicle at the front, walk around the back and then open up the wrong panel and set to work believing the circuit is dead. All of which can happen easily enough; according to the Health and Safety Laboratory, as much as 90% of incidents involve human factor causes.
Lack of maintenance is also one of the bigger issues as when companies have to cut costs, a common feature of today’s economy, maintenance is usually the first to be forfeited.
Lack of maintenance can then lead to insulation and equipment failure. Once damaged, whether through substandard parts, lack of servicing or just wear and tear, contact between user and the electricity suddenly becomes much more available.
- A common myth within the workplace comes from the job veterans who have never even heard of an Arc Flash, let alone seen one. As we identified earlier, this is a hazard you can’t see or hear so whilst we hope you won’t ever experience an Arc Flash blast, it doesn’t mean that it can’t happen.
Electrical accidents occur much more often than companies would like to acknowledge. A survey conducted by the Electrical Safety Foundation International (ESFI) asking electrical engineers if they’d received an electrical shock in the last 12 months showed that 98% of them said ‘yes we have.’
When working in an Arc Flash risk area, Fire Resistant clothing just won’t cut it. As the name implies, Arc Rated clothing fabric is subjected to a series of arc flashes to determine how much energy it can block before it is likely to cause the wearer a second degree burn, 50% of the time. This amount is known as the Arc Thermal Protective Value (ATPV). The ATPV is measured in calories of heat energy per square centimeter (Cal/cm²). The higher the arc rating value, the greater the protection.
Arc Flash can be so easily prevented or mitigated by following the ERIC PD
hierarchy of controls: Eliminate, Reduce, Isolate, Control, PPE and Discipline.
By following these measures, and having something like our ERIC PD mascot around site, it is easy to go over the checklist in your mind every day before work to help stay safe around electricity.
- Don’t forget, distance is your friend! If you have no need to be in that switch gear room or substation, don’t be. And if you can operate the equipment remotely, then do so.
- And finally, PPE is your last line of defence. PPE may be used as a temporary control measure until another alternative is installed however, that said, there are often many situations where wearing it is necessary and that’s why getting the right PPE is absolutely crucial.