An electric arc is one of the most devastating incidents that can occur in an electrical installation. Besides immediate danger to life for persons, it often leads to total destruction of switchgear and prolonged downtime. Understanding does not start with guesswork, but with arithmetic.
As an installation manager or engineer, it is your job to ensure safety. A thorough Arc Flash Study gives you the data you need to select the right PPE and optimise your safety settings. Avoid false safety; base your safety policy on facts.
Short on time? These are the key points every technical professional needs to know:
This knowledge page is written for professionals responsible for the safety and continuity of heavy electrical installations (Low Voltage & Medium Voltage):
An arc (in English: Arc Flash) is basically a short circuit that does not pass through a fixed connection, but through the air. Think of it as lightning, but trapped inside your distributor or switchboard. The air, which normally insulates, ionises and becomes a conductor of plasma.
The equation: Imagine a short circuit as a tap breaking open and spraying water. An arc is like that water instantly turning into steam and blowing up the entire bathroom. It's not just about electricity; it's about an explosive release of energy.
Why is attention to electric arcs essential?
The impact of an arc incident is often underestimated. The consequences are threefold:
Personal injury: Heat is more intense than the surface of the sun. Fatal burns can occur even a few metres away, not to mention the damage caused by the pressure wave (Arc Blast), flying copper and glare.
Economic damage: A distributor in which an arc has occurred is often a total loss. The replacement time of specific components (such as busbar systems or circuit breakers) can take weeks to months.
Compliance and Liability: As an employer, you are obliged to provide a safe working environment. Without up-to-date arc calculations and associated labelling, you may not comply with RI&E obligations.
An arc itself is a sudden event, but the risk factors have often been present in your installation for a long time. Pay attention to the following signs during inspections:
Want to know more about electric arcs and how to deal with them? Check out our training!
Statistics show that a significant proportion of incidents occur during operations (maintenance, measurements, switching).
Wearing Personal Protective Equipment (PPE) does not prevent an arc, but it does determine the difference between 'scare' and life-threatening trauma. In the safety hierarchy, it is the last step (last resort), but a crucial one.
No cotton or polyester Standard workwear is more dangerous in an electric arc than no clothing. Synthetic fabrics melt directly into the skin, aggravating burns. Arc-resistant clothing (Arc Rated) is self-extinguishing and thermally insulating.
Selection based on facts (Categories) You choose PPE not on a guess ("just do the heaviest suit"), but on the basis of calculated incidental energy (cal/cm²). Clothing that is too heavy is uncomfortable and increases the risk of errors due to heat stress or limited visibility.
Eliminating arc risks starts with insight. There is no 'one-size-fits-all' solution; it requires a layered approach.
1. The basics: Arc Flash Study
You cannot manage risks if you do not quantify them. An arc calculation, often performed according to the US standard IEEE 1584, calculates the incident energy at various points in your installation.
2. Engineering measures (Hardware & Settings)
3. Operational measures
1. Quick wins (Settings & Maintenance):
This label must be clearly displayed on each distributor according to NEN 3140 and international standards (such as NFPA 70E). It tells the technician at a glance:
Note: DC installations and labels Increasingly, we see arc risks in DC (direct current) environments, such as in large battery storage systems (BESS), data centres or PV installations. A DC arc behaves differently from AC and is often more difficult to interrupt (no zero crossing). Standard AC calculations are not sufficient here; make sure your labels are based on specific DC simulation models to avoid false safety.
An arc study is complex. You need specialist help when:
You doubt whether your current protection settings are still correct for the current load.
You work with complex grid structures (rings, emergency generators, PV installations) that affect short-circuit currents.
The calculated arc energy in your installation is so high that standard PPE is not sufficient ("Dangerous" category).
You seek a balance between maximum safety and selectivity (preventing unnecessary outages).
Deepen your knowledge with these related topics:
Gambling with safety is not an option. Do you doubt the current risks in your installation or have your security settings not been checked for years? Our engineers will be happy to help you with a clear diagnosis.
HyTEPS
Beemdstraat 3
5653 MA Eindhoven
