How to Prevent Arc Flash
There are many inherent dangers in working with electrical equipment and circuits. Electricity can be extremely violent in some forms, and few more so than when it manifests as an arc flash. Arc flash occurs when there is a fault that causes an electrical arc to form between two points. This happens faster than the blink of an eye, and can have devastating consequences.
During an arc flash – which can last a very, very short time – a simply colossal release of energy can occur. This can cause extreme heat and light, enough to melt metal and other substances in close proximity, an also very severe burns and other injuries to persons within range.
Arc flash occurs in many different circumstances, and it is essential that anyone dealing with electrical circuits, switching systems and other areas with any level of voltage take all the precautions they can to prevent it happening. How do you prevent arc flash? Let’s have a look at that problem.
Precautions to Take
The simple fact is that arc flash can occur in any electrical circuit. It is more intense – and therefore more dangerous – in higher-voltage circuits, where it can be very, very dangerous indeed. It can occur in both closed environments – control and switching boxes, for example – and in open areas, perhaps where power lines are being repaired or serviced.
There are industry guidelines that are in place to help prevent the possibility of arc flash, but it remains the first priority to isolate any energy supplies that are associated with the equipment, and to de-energise the equipment involved.
However, there is a problem in that de-energising can in itself be a cause of arc flash, as if there are faults inherent, it may cause the same release of energy. For this reason, the use of personal protection equipment (PPE) and clothing is highly recommended.
PPE and Arc Flash
Another precaution to take is that of a detailed risk assessment of the area involved. Where electrical circuits are concerned, there should always be an assessment carried out to check for the risk of arc flash, bearing in mind the intensity of the arc can be influenced by voltage, amperage and many other factors. Therefore, a high-voltage circuit will present a greater risk than a 220volt circuit, for example.
The correct procedures for shutting down circuits should also be followed, as it is often when shut down and switched on that arc flash is most likely. This is all part of necessary training for persons involved in areas where arc flash is a possibility, as is the use of PPE.
The main injuries caused by arc flash are burns – often very severe thanks to extreme temperatures and molten debris – plus damage to sight and hearing, caused by the intense light and loud noise. Protective equipment should extend to clothing that protects against heat, visors for the light and also hearing protection, and there is plenty more available from the best suppliers of arc flash PPE equipment.
There is also a need for metering equipment, which can be used to check the circuit for residual energy before work begins. Turn to Power Meters for recommendations. This will indicate the need for further de-energising, and if this is not correctly assessed, the consequences can be unthinkable – arc flash can easily cause death in many cases.
It is clear, then, that while the possibility of arc flash cannot be completely eliminated, and there are many other causes than those we have briefly mentioned, prevention and protection is the approach that needs to be taken. The use of correct and accurate metering and risk-assessment, plus sensible training and protective equipment, is the way forward.