There are many inherent dangers involved in working with electricity. It may be a vital part of our lives both at home and in the workplace, but we cannot underestimate how powerful it can be. In high-voltage circuits especially, the problem of arc flash should never be overlooked. Should it occur, and there are many instances in which it might, it can have quite devastating consequences.
Arc flash is a curious phenomenon, and one that can be very spectacular. Put simply, it occurs when an electrical arc is formed in the air, i.e. without a physical bridge between the two contact points. The result, at high voltages, is a very dangerous release of fantastic amounts of energy in the form of light and heat, which will not only damage any material in close proximity, but will undoubtedly result in injury to the persons concerned.
You may have experienced arc flash on a minor scale in the home: have you ever been present when an incandescent light bulb ‘blows’? This happens when the filament, which connects the two contact points, breaks. In that instance, you may see a bright flash of light – the electrical arc jumping across the points – and hear a ‘pop’ which is the explosion. That is an arc flash, yet it is safely contained.
What can we do about arc flash and prevention? In truth, as it is often caused by unexpected faults, it cannot be 100% prevented, but there is plenty that can be done to minimise the risks and to protect those involved.
Prevent and Protect
Minimising the risk of arc flash involves understanding what causes it, and our brief explanation above will be expanded upon when you have your workforce fully trained in what it is all about. There are several things that can be done to keep its risk to a minimum.
First, you should always ensure that the correct shut-down and start-up procedures are strictly adhered to where high-voltage electrical circuits are concerned. This is because switching on an electrical circuit is one of the highest risk points when electrical arcs are concerned. A sudden surge of power through the circuit can cause any faults to be uncovered, and an arc may form to bridge them, with dire consequences.
Another procedure you need to undertake is the de-energising of any equipment that is involved. Electrical energy can build up on metal surface and elsewhere, and this should be checked – as should any residual voltage in the system – carefully with correct and accurate metering systems, like those sold by Power Meters, before any action is taken. De-energising can cause an arc if not correctly carried out, so it is essential that careful steps are followed.
The Right Clothing
As well as following procedure, the correct protective gear should also be worn by anyone in the potential risk zone – that is close to the point where arc flash may occur. The main injuries caused are as follows, so this should give you an idea of what you need to obtain for your workforce to wear:
- Third-degree burns to the face, hands and arms, often irreversible
- Loss of sight due to intense light radiation
- Hearing damage thanks to the loud explosion
- Internal damage caused by inhaling extreme heat
Therefore, it is easy to see that all involved should be wearing protective clothing that covers the arms and hands, plus a face mask with a visor to protect against the light, and ear protectors for the sound.
Make sure you are fully up to speed with what is needed, and you will keep your team s safe as possible at all times.