Image may be NSFW.
Clik here to view.
The dangers of working with electricity are not unknown, but there are some potential problems that can never be 100% eliminated. One of these is arc flash, and it is a hazard not just with high-voltage equipment, but also with that which is lower-rated. What is arc flash, and why is it such a danger?
Essentially, arc flash is a release of energy, caused by an electric arc that is created between two contact points. In happens very quickly indeed, and can involve extremely high temperatures that, while present only for a very, very short time, can cause serious damage – and also potential injury to a person.
There are different types, and intensity, of arc flash, but each is as dangerous as others, and all can be protected against. The use of personal protection equipment, including clothing that may prevent against burns caused by the flash, and also correct and accurate metering equipment are both recommended protections against arc flash, and those who are trained in dealing with equipment that may cause an arc must be trained in what to do if one is experienced.
Types of Arc Flash
A confined arc flash happens within an electrical distribution box, for example, and is contained on three sides. This can happen in fuse and switching boxes, and as it is contained, the flash towards the person performing the task, and can burn their hands and face.
An open flash is one that is not contained; this can perhaps occur when working on powerline connections, for example, and the flash takes the form of a 360-degree explosion. Such is the heat of an arc flash that it can, in mere seconds, melt metal, so the operator is liable to be hit by molten metal that can cause serious burns and other injuries.
These are further reasons why protective clothing and correct metering and understanding of the problem are all necessary precautions, and there are many different situations in which a flash can occur. Indeed, it can be as simple as switching a circuit back on. Turn to Power Meters for more information on the proper equipment needed.
Arc Flash Injuries
As we have already explained, arc flash may last a very short time, but the intensity of the heat and energy it disperses can be colossal. This can be affected by many factors including but not limited to:
- Voltage
- Amperage
- Confined space
- Closure time
- Arc distance
The type of circuit involved – whether single or 3-phase – is also a potential influence, and it should be known that voltages above the standard 220v present the greatest potential danger.
Arc flash injuries can be extremely severe, which is why protective PPE is always necessary when working with electrical equipment, and can be such as:
- 3rd degree burns caused by the molten metal and the extreme heat; these can often be irreversible
- Loss of sight; this is caused by intense magnetic radiation experienced during the flash
- Internal problems caused by heat inhalation
- Hearing loss caused by the explosion
The above may be permanent in some cases, and it is worth knowing that arc flash can indeed cause fatalities, thanks to the sheer intensity of the energy released and the effect it can have on those in the immediate area.
Clearly, then, arc flash can be very dangerous indeed. The precautions taken against it should not be limited to protective equipment, but should also include intensive training in the causes and effects of the problem, as well as the steps that should be taken before working on any electrical circuits. There is no 100% guarantee that arc flash will not occur, so always be prepared is the best approach.