Arc Flash Explained: What You Need to Know to Stay Safe on the Job

Key Takeaway

Arc flash remains one of the most dangerous electrical hazards on the job site. By calculating incident energy, following NFPA 70E guidelines, and selecting arc-rated, high-visibility PPE that matches the risk level, safety managers can protect teams from severe burns, blast injuries, and compliance failures. The key is choosing gear that’s tested, labeled, and designed for both visibility and thermal protection.

What Causes an Arc Flash and How Dangerous Is It?

An arc flash is a rapid release of energy caused by an electrical fault that allows current to travel through air, creating an explosion. Temperatures can exceed 35,000°F, enough to vaporize copper and cause third-degree burns at distances of several feet.

The arc itself is just one part of the hazard. Workers are also exposed to:

• Thermal radiation (intense heat and light)
• Pressure waves that can collapse lungs or rupture eardrums
• Molten metal spray that causes deep burns
• Sound levels over 140 dB, comparable to a gunshot at close range

According to NFPA, arc flash is one of the top causes of serious injuries in the utility, manufacturing, and construction sectors. In 2023, there were 142 deaths from electrical exposure in the U.S. alone.

Understanding how arc flash occurs is only the first step. To reduce risk effectively, you also need to measure how severe the energy release could be, and that’s where incident energy comes in.

How Is Incident Energy Calculated and Why Does It Affect PPE?

Incident energy is the amount of thermal energy (cal/cm²) a worker is exposed to at a given distance from an arc event. This is the core metric used to define PPE requirements under NFPA 70E and IEEE 1584.

Here’s how it works:

• An engineer models a specific electrical system using IEEE 1584-2018.
• They calculate the expected energy release based on system voltage, fault current, clearing time, and working distance.
• This determines the arc flash boundary and minimum PPE rating.

That incident energy value determines the minimum arc rating your PPE must meet. With the risk level defined, the next step is understanding how arc-rated clothing is engineered to shield workers from that intense thermal exposure.

What Does Arc Rating Mean for Protective Clothing?

An arc rating tells you how much heat a piece of clothing can withstand before causing a second-degree burn. The higher the rating, the more protection it offers.

• AR (Arc-Rated) clothing is tested using ASTM F1959.
• It must self-extinguish and not melt or drip.
• Ratings are expressed in cal/cm².

According to OSHA, many arc flash injuries result from clothing catching fire, not the arc itself. Arc-rated clothing is also flame-resistant (FR), but not all FR gear is arc-rated. That’s why choosing the right protection matters.

Of course, arc rating is just one part of the equation. In many work zones, visibility matters just as much, and that adds a second layer of PPE requirements.

Why Should Arc-Rated PPE Also Include High-Visibility Protection?

Workers in utility and construction environments often face dual hazards: low visibility and arc flash risk. That’s why ANSI 107-compliant high-vis gear that’s also arc-rated is critical for:

• Roadside electrical crews
• Substation and linemen work
• Airport ground operations with energized systems

However, not all ANSI gear meets arc rating requirements. Look for labels with:

• Arc rating (ATPV or EBT, cal/cm²)
• Compliance to ASTM F1506

So how do you find gear that balances both safety requirements? 

Who Designs PPE That Protects Against Both Arc Flash and Low Visibility?

Kishigo builds gear that delivers both real arc flash protection and dependable visibility, so workers stay protected and stay seen in every environment. We design arc-rated, high-visibility workwear for the conditions you face daily. That means clothing that handles real heat exposure, rough weather, tight spaces, and long shifts without getting in the way.

Here’s what makes Kishigo different:

• Arc-rated materials tested to meet or exceed NFPA 70E, ASTM F1506, and ANSI 107
• Invisible fusing and reinforced stress points that hold up through constant movement and repeated laundering
• Breathable mesh panels that help control heat in hot or enclosed spaces
• Ergonomic pocket layouts and tech-friendly features that support the way crews work

Workers need gear that supports them, not gear they work around. Whether you're racking a panel, climbing a structure, or handling roadside outages, Kishigo helps you stay safe, visible, and comfortable.

Explore Kishigo’s arc-rated workwear or talk with a product expert to get recommendations tailored to your tasks and hazard levels.

FAQ

What happens if arc-rated clothing is worn incorrectly?

Improper fit, layering non-compliant garments underneath, or leaving jackets unzipped can reduce protection and increase burn risk during an arc flash.

How do I know if my arc flash PPE is still compliant?

Check garment labels for ASTM F1506, NFPA 70E, and ANSI 107 markings. Inspect for wear, damage, and laundering instructions that could affect its arc rating over time.

Can you layer arc-rated garments to increase protection?

Yes, if both layers are arc-rated and tested together. The total arc rating will depend on how they perform as a system, not just the sum of individual ratings.

How does arc flash clothing help prevent burn injuries?

Arc-rated clothing is designed to self-extinguish and resist melting. It limits heat transfer to the skin, reducing the chance of second-degree burns during an arc event.

Why isn’t heavy cotton a safe substitute for arc-rated gear?

Cotton can ignite and continue to burn, making injuries worse. Arc-rated clothing is tested to resist ignition and won’t melt or drip under high heat.