What are the dangers of Arc Flash?

What are the dangers of Arc Flash?

In previous articles we’ve discussed 'What is Arc Flash', 'Arc Flash Analysis' and 'Arc Flash Safety' but now we really want to give you a good idea of what the consequences could be.

See video version here:

In this article, we will be going over what are the dangers of Arc Flash.

1. Extreme Heat
2. Fireball
3. Molten Shrapnel
4. Metal Vapour
5. Blinding Light
6. Deafening Sound 

So... we’ve mentioned before on how this all works but let’s just go through it quickly.

An Arc Flash is a massive release of energy from an electrical distribution system and is typically caused from a foreign object (corrosion, finger, tools, mouse, etc.) coming too close to the exposed energized conductors.

What happens next is an Arc will form through the air... followed by an inrush of current. There is so much current, so fast that everything becomes superheated and explodes...

If you are standing in the way, then this is the dangers you’ll be faced with.

See video explanation here:

Extreme Heat

First and foremost, we have an insane amount of heat energy.

We refer to this as incident energy and it’s measured in calories per centimetres squared. It takes about 1.2 cal/cm2 to cause a second-degree burn.

This heat energy is not a fireball or wall of flames... it’s heat energy similar to the energy you receive from the sun... so it’s kind of like getting a sun burn.

The only thing about an Arc Flash is that, on average, the temperature is actually 4 times greater than the surface of the sun! That would be a really bad sun burn.


Next, we have a fireball... this is what most people are visualising when they think of an explosion or an Arc Flash event.

The fireball will obviously burn you... but more importantly, it will ignite your clothing.

If your clothes catch fire, you will be in big trouble because things will continue to burn long after the Arc Flash is extinguished.

Molten Shrapnel

When copper and aluminium become heated to 20,000 degrees Celsius, they tend to melt... they also tend to expand instantaneously to about 60,000 times their normal size.

This creates quite the bang, sending millions of pieces of molten shrapnel flying in every direction.

Metal Vapour 

Along with becoming superheated... some of the metals will vaporize sending a cloud of harmful gases in your direction.

Breathing these gasses can lead to serious health issues and maybe even leave you unconscious.

Blinding Light

At the moment if ignition, an Arc Flash will produce both ultraviolet and infrared light... someone like a Welder’s Arc, but a lot more intense.

This light exposure typically blinds anyone in the area (at least momentarily, if not longer).

Deafening Sound

Accompanying any explosion, you would expect to hear a sound.

And, when copper expands to 60,000 times its normal size (as does happen in an Arc Flash) it’s going to move a lot of air... which makes a big loud sound.

A typical Arc Flash would be as loud as 160 decibels... which is enough to rupture your eardrums.

What you can do

Well now that you understand an Arc Flash is nothing to sneeze at you’ve got to come up with some mitigation techniques in order to protect yourself.

Arc Flash PPE is a great place to start and over the next few weeks we will be going deeper and deeper into solutions for you. See our full collection here.

See below our STRATA Arc FR Garment being tested against a treated garment. 

Previous article Arc Flash Safety Procedures
Next article Arc Flash Analysis

Leave a comment

Comments must be approved before appearing

* Required fields