Arc flash is one of the most serious electrical hazards present in industrial and commercial environments, yet it remains widely misunderstood. Many duty holders are aware that arc flash incidents can lead to severe injury and equipment damage, but far fewer understand how the risk develops or what is required to manage it effectively. 

For us as electrical engineers, the message is simple: duty holders do not need to know the technical details behind every calculation, but they do need a clear understanding of their responsibilities and the factors that influence arc flash risk. That understanding is essential for ensuring the safety of anyone working on or near electrical equipment.

What Arc Flash Risk Really Means

An arc flash occurs when electrical current leaves its intended path and travels through the air, creating a sudden release of heat, pressure and intense light. The temperatures involved can be extremely high, and the resulting pressure wave can cause tools, debris or equipment parts to become airborne. Even at low voltages, an arc flash can be strong enough to cause burns, hearing damage or loss of visibility.

Because arc flash does not always require direct contact with conductors, even personnel working nearby may be exposed. This is why duty holders must understand the risk, not from a technical perspective, but from a practical and duty-of-care perspective.

Arc flash happens quickly. It happens silently until the moment it occurs. And in many cases, it happens because the underlying risk was not fully understood.

Why Duty Holders Play a Critical Role

A duty holder is anyone responsible for the safe operation, maintenance or management of electrical systems. This can include site managers, facility owners, senior engineers, and health and safety professionals. Regardless of job title, the responsibility remains the same: ensuring that electrical work can be carried out safely and that foreseeable risks are controlled.

Managing arc flash risk requires duty holders to:

• Understand the condition of the electrical system

• Ensure system documentation is accurate and up to date

• Commission appropriate risk assessments

• Ensure protective devices operate as intended

• Facilitate relevant training and safe work practices

• Provide suitable equipment and suitable PPE

Why System Design Plays a Major Role in Arc Flash Risk

Arc flash does not develop in isolation. The behaviour of an arc flash event is heavily influenced by the way the electrical system is designed, configured and protected. Factors such as protection settings, cable routes, transformer arrangements and switchboard layouts all affect how a system behaves during a fault.

If the electrical network has been modified, extended, or upgraded without updated system studies, duty holders may be operating with an outdated view of the risks. In some cases, this can lead to an underestimation of arc flash severity. In others, it may result in overly conservative boundaries or unnecessary restrictions on maintenance activities.

What Happens When Arc Flash Risk Is Not Understood

When arc flash risk is overlooked or misunderstood, the consequences can extend far beyond the incident itself. Even a small arc flash event can lead to:

• Injury to personnel working near the equipment

• Significant damage to switchgear or distribution boards

• Extended downtime while repairs are carried out

• Unexpected operational disruption

• Increased maintenance or replacement costs

• Questions from insurers or regulators about duty-of-care compliance

Arc flash incidents often reveal deeper underlying issues such as outdated drawings, incorrect protection settings or unrecorded system changes. These hidden weaknesses become clear only after something has gone wrong.

Why Arc Flash and Fault Level Assessments Matter

Arc flash and fault level assessments allow duty holders to make informed decisions based on how the electrical system will behave under fault conditions. These assessments are not about providing complex data; they exist to highlight risk areas in a way that is practical and easy to understand.

An arc flash and fault level assessment helps identify:

• Where arc flash hazards are present

• How severe a potential incident could be

• Whether existing protection systems minimise the risk

• Whether equipment is appropriately rated

• Where improvements or mitigation  may be required

Incident Energy: What Duty Holders Need to Know

Understanding the severity of Incident energy levels is a key outcome of an arc flash  assessment. While the calculation behind it is technical, the principle is simple: it represents the thermal energy someone could be exposed to at a given distance during an arc flash incident.

Duty holders should understand incident energy not as a number but as an indicator of:

• How close someone can safely work to an electrical asset.

• What level of PPE  is required.

• Whether mitigation steps should be considered.

• Whether protective devices are clearing faults fast enough.

The purpose of incident energy analysis is to support safe working practices, not to burden organisations with technical information.

Practical Steps Duty Holders Can Take Today

Even without technical expertise, duty holders can greatly reduce arc flash risk by taking practical, straightforward actions:

Keep system documentation accurate

Outdated drawings or missing protection information can lead to incorrect assumptions about risk.

Ensure assessments reflect the current system

If changes have been made, or if equipment is ageing, assessments may no longer be valid.

Review labelling and signage

Clear, consistent labelling ensures personnel understand risk boundaries before work begins.

Promote a culture of electrical safety

Training and awareness are essential. Personnel must understand how to identify hazards and respond appropriately.

Coordinate protection systems

Protection devices must operate in a way that reduces the duration of faults. This mitigation alone can significantly reduce incident energy levels.

Engage competent electrical specialists

Reliable assessments and advice come from experienced engineers who understand fault behaviour and protection strategy.

Why Arc Flash Risk Must Be Reviewed Regularly 

Electrical systems rarely remain unchanged. Loads increase, equipment deteriorates, operational demands shift, and new technology is introduced. Each of these changes alters how the electrical system behaves and therefore influences the arc flash risk.

Duty holders have a responsibility to ensure assessments remain current. A study carried out several years ago may no longer reflect the system today.

NFPA 70E recommends an arc flash risk assessment must be updated whenever a major modification or renovation takes place. The assessment must also be reviewed periodically, at intervals not exceeding 5 years.

Get in Touch for More Advice on Arc Flash

Arc flash risk is a real and manageable part of electrical safety. Duty holders are not expected to become protection engineers or calculation experts, but they are expected to understand the hazards, recognise their responsibilities and ensure the right assessments and controls are in place.

With up-to-date system information, coordinated protection and clear risk awareness, organisations can significantly reduce arc flash hazards and maintain a safer working environment.

For more advice on arc flash and fault level risk, don’t hesitate to get in touch with our expert team at Covol Engineering.