Anywhere in a facility where high electrical current can exist should be properly labelled with arc flash warnings. To minimise the risk of an Arc Flash occurring your plant should identify where the biggest dangers are.

Faulty installation – if equipment is installed incorrectly it can make it difficult for electricity to follow the intended path.

Corrosion – corrosion can create a path outside the wire.

Material failure – if a wire is damaged to the point where the electricity has trouble passing through, there may be less resistance for it to go outside the wire.

Condensation – when condensation forms, electricity can escape wiring and travel through the water.

Accidental touching – if a person touches a damaged area – the electricity can flow through their body or at least out of its normal path.

Dropped tools – if a tool is dropped on a wire, it can damage it and allow electricity to pass into the tool, from there it can find another path to travel.

Dust – in dusty areas electricity may be passing outside the wiring or other equipment through the dust.

Things that can create a path with lower resistance include:

It could also be the result of someone working on a piece of equipment that makes it possible for electricity to escape from its normal path.Įlectricity will follow the path of least resistance, so an arc flash will not necessarily occur as soon as a piece of equipment is damaged, instead it will continue to work as normal until another path with less resistance becomes available.

This is determined by the potential energy present and a variety of other factors including air temperature and humidity.Īn Arc Flash can be caused by a wide range of reasons but often the cause will be a damaged piece of equipment such as a wire. The exact distance an arc flash can travel is known as the arc flash boundary. The arc blast will travel towards a ground of some type. These explosions generally occur without any warning. Arc Blasts and the resulting heat can lead to fires, pressure waves and flying shrapnel that result in serious damage to people and property. When an Arc Flashes happens they create a very bright light and intense heat and have the potential to create an arc blast. Most 400v and above electrical machinery has the capacity to cause an Arc Flash. An Arc Flash can last anywhere from a fraction of a second to several seconds. An Arc Flash is an electrical explosion due to a fault or short circuit where electric discharge travels through the air between conductors or from a conductor to a ground.

Arc flash boundary image 2018