Updated on 25.06.2025.

Working on electrical installations is not without danger. One of the most dangerous is the electric arc, also known as arc flash. This sudden discharge of energy can lead to serious, sometimes fatal, injuries in a split second.

What are the exact dangers? And can do you best protect yourself? You can read about the explanation in this blog post.

What is an arc flash and why is it important?

An arc flash is an electrical discharge of high or low voltage current between conductive elements. This often happens due to human error, such as dropping a tool between the live parts of an installation.

The current that is released by an arc flash can cause a large amount of heat energy to explode. The consequences can be huge:

• Explosion of heat energy, up to 20,000°C
• Fatal or severe burns

Besides a heat explosion, other risks include:

• Release of toxic copper and steel fumes (due to melting of the electrical system)
• Heavy smoke resulting in possible lung damage
• Sound waves up to more than 140 dB
• Pressure waves with flying splinters from conductors
• Ultraviolet/ infrared light
• Other thermal hazards due to heat generation

For all these hazards, Vandeputte has put together a specific product selection , along with everything you need to know about ensuring the best protection.

How is arc flash risk calculated?

The arc flash risk is expressed as "incident" energy in cal/cm² and represents the radiation that strikes a worker's skin when an arc flash occurs. This mainly involves radiant energy.

From a minimum of 1.2 cal/cm², for one second, there is a risk of second-degree burns. The more calories, the higher the incident energy and therefore the better the protection must be!

However, the determination of cal/cm² is influenced and complicated by several (variable) factors:

• Current and voltage: high or low voltage
• Duration of arc: depends on the speed at which the circuit breaker turns off (the faster, the lower the risk)
• The distance of the worker from the installation: the hazard is mitigated, the further away they are (reduction factor 4)
• Power of the short-circuit arc (kA)

Ideally, employees should work at a distance from the control cabinet so that they cannot suffer second-degree burns if an arc flash occurs. Are you working within the "safe arc flash limit"? Then the necessary PPE is necessary.

How can you protect yourself against an arc flash?

A proper risk analysis and awareness will help you reduce energy levels and make work procedures safer.

Whatever remains is called the “residual risk”. That is what PPE protects you from.

The right PPE for arc flash hazards

Before choosing the correct protective clothing and other PPE, it is important to carry out a risk assessment by measuring the potential incident energy an arc flash could cause, and to which a worker could be exposed.

The distribution of thermal risks over the human body are distributed as follows (based on accident statistics):

Distribution of injuries in arc incidents:

• + 60% on forearms and hands
• 50% to head
• < 10% on torso and legs

Hands and head are often inadequately protected!

1. Arc flash clothing

How do you determine the arc resistance of clothing? The legislative framework on this is set out in the international standard IEC 61482-2. From this, two test methods have been created. Both methods may be chosen - independently - by the garment manufacturer.

1. Box-test

This involves exposing the fabric to an electric arc with a force of 4kA or 7kA, where the heat transfer does not result in second-degree burns. The test is then repeated on a garment. This garment should remain functional after exposure (seams should not burst, accessories such as zips should remain functional). If both results are positive, the garment can be marked category 1 (4kA) or 2 (7kA).

2. Open Arc test

In this test, arc resistance is expressed as the Arc Thermal Performance Value (ATPV ). This value is the maximum thermal incident energy (cal/cm²) at which a material protects the wearer from second-degree burns.

The advantage of this method is that matching PPE can be chosen in a more targeted way based on this ATPV value. The Open Arc test is often seen as the "best practice" method for selecting the right personal protective equipment.

Layer principle

When choosing protective clothing, it is important to know the thermal protection of the overall clothing concept being worn.

Each item of clothing separately (undergarments/intermediate clothing/rainwear) has a certain ATPV value. The values of the different layers can be added up, but in practice the protection value will be higher than the sum of the individual ATPV results. This is because the layers of air between the different layers of clothing provide additional thermal protection. This layer combination can, if desired, be tested by independent testing agencies.

Important: To protect against extreme heat, garments are often double-layered at the front. The extra fabric mass provides greater protection against high incident energy. Note that CE test results (Box test or ATPV) must be stated separately for single and double-layered components.

See our arc flash clothing

B. Arc flash hand protection

There is currently no harmonised standard or test method for gloves that protect against the thermal risks of an arc flash. (Not to be confused with the risk of electrocution - Standard EN 60903.) As with clothing, ATPV testing is often used by manufacturers.

You can choose from:

• Gloves that protect against electric arcs as well as electrocution (e.g. composite)
• Gloves that only protect against arc flash (provided other insulation is present)

Always be careful! Never use latex gloves while working with an arc flash risk. Latex will melt due to thermal impact/high temperature and cause severe burns. Even the seams of leather outer gloves can tear!

View our arc flash hand protection

3. Arc flash head and face protection

The great advantage of a full protective hood is that it protects the entire head from the risks of the electric arc, such as flying metal, hot substances and/or fumes. They are tested to EN50365 standard and are insulating when working at up to 1000 V.

The face shields are approved according to general standard EN166. These are additionally tested according to protocol GS-ET-29 regarding protection against the thermal risks of an electric arc. This will also include an ATPV value in cal/cm². Tinted screens are recommended for extra protection against the bright light impact and UV radiation associated with an arc.

Since this hazard often causes great damage to the head, it is also important to wear the correct personal protective equipment on this area of your body. Usually, a combination of a helmet with screen, ear muffs and neck protection is appropriate.

Three major groups can be distinguished:

• Without helmet, with protective cover: for switching work without risk of falling objects or live catenary systems
• With helmet: electrically and thermally insulated, also protects against falling objects (optional neck protection)
• With helmet and hood: full protection of head and face for increased risk

View our arc flash face protection

View our arc flash head protection

D. Arc flash foot protection

As with hand protection, there is no separate standard for foot protection for arc flash hazards because the risks in this area are small.

Insulating overshoes or boots should always be worn where there is a combination with electrocution risk.

View our arc flash foot protection

How is it different from other risks?

Some risks seem similar but are different... For example, electric arc, electrocution and static risks are not the same and each requires a different approach and PPE choice.