What is Arc Flash?

Electricity is an essential part of our daily lives – whether in domestic or industrial terms – and we do tend to take it for granted. It’s worth remembering, however, that electricity can also be extremely dangerous. Indeed, when dealing with electrical circuits, arc flash is one of the biggest potential dangers of all, so what is it, and what do you need to do to prevent and protect against it?

Arc flash is when an electrical connection is made through the air. For a small and simple example, think of an old-type filament light bulb. When that bulb ‘blows’ – when the filament breaks – for a brief instance a connection may be made between the two points it was connected to, across the gap. You may see a bright flash and hear a ‘pop’; that is very small arc flash.

Now, imagine that on a larger scale, perhaps with a massive voltage as required for an industrial circuit. What happens during such an arc flash is that an enormous amount of energy – in the form of light and heat – is released as a sort of explosion. This happens in a very, very short time, and yet the energy released can result in irreversible burns, other damage to the people close by, and even – quite easily – death.

Preventing Arc Flash

Arc flash is an ever-present problem that cannot be 100% guaranteed against – that is the nature of electrical circuits – yet there are many things that can be done to prevent and protect against it. Often, it is caused by a fault in the circuit, so there is a requirement for regular checks – especially in higher-voltage equipment – to make sure everything is working correctly and that such faults are not present.

Also, it is worth knowing that arc flash is more likely to occur when a circuit or system is being switched on or off; this is because of a surge of power and energy through the circuit. Hence, there need to be set routines as to switching circuits back on once they have been turned off. This is particularly important in switching boxes, where the arc flash can have devastating consequences.

De-energizing equipment – that is getting rid of residual energy that may have built up during operation – is also a vital protection against arc flash. Yet, it remains a fact that the very process of de-energizing can also be a cause of arc flash, as it releases a potentially dangerous source of energy. This is why it is important that accurate metering is carried out and the correct routines are followed when carrying out any such procedure.

Protective Clothing

Burns are the most common injury from arc flash, and they can be very severe, especially on the hands, arms and face which may be closest to the arc. Protective clothing provided by Arc Flash that is designed to give as much as possible protection against the heat and light energy is highly essential, and it is also imperative that the eyes – which can be affected to devastating results by the electromagnetic radiation – and the ears are also given the best possible protection.

In short, arc flash is an electrical phenomenon that happens when a circuit is created in the air, and in a very, very short time it results in the emission of a fantastic amount of energy that can be extremely damaging to equipment, and very dangerous and even fatal to those in close proximity. The prevention of and protection against arc flash should be part and parcel of your training, and anyone involved in working with high voltage equipment should be fully trained for every eventuality.