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Arc Flash and Fault Level Assessment
An arc flash fault occurs when electrical current leaves its intended path and travels through the air between live conductors, between phases, or between a conductor and earth. This creates an electric arc that can release intense heat, light, sound, molten metal and a pressure wave. This type of electrical flashover is dangerous because the energy released can cause severe burns, arc flash injuries, equipment failure, electrical fire and serious injury to nearby electrical workers.
An arc fault describes the abnormal arcing condition. An arc flash describes the release of energy, heat and force that can occur when that fault develops in high-energy electrical equipment. Arc flash hazards are especially important in industrial and commercial electrical systems where fault current, voltage, protective devices and equipment condition can all influence the severity of an incident.
Fault level is the amount of fault current that could flow through an electrical system during a short circuit, earth fault or abnormal fault condition. It shows how much electrical energy could be available at a specific point in the system if something goes wrong. This matters because circuit breakers, switchboards, cables and other protective equipment must be able to withstand and interrupt that fault current safely.
A fault level assessment helps confirm whether electrical equipment is suitably rated, whether protective devices can operate correctly, and whether parts of the system are exposed to avoidable risk.
Fault level is calculated by assessing how much current could flow during a fault and what limits that current within the electrical system.
A fault level calculation considers the incoming power supply, available short-circuit current, transformer data, cable lengths, cable impedances, earthing arrangements, protective devices, equipment ratings and the layout of the electrical installation.
Higher system voltage and lower impedance can increase available fault current. Higher impedance usually limits current flowing during a fault. In commercial and industrial systems, accurate modelling is required because multiple assets, protective devices and network conditions can affect the result.
Covol Engineering uses industry-standard SKM Power Tools software to model your electrical distribution system using protection details, equipment data and cable impedances. This allows our engineers to calculate fault levels at fault-rated switchboards and compare the results against equipment ratings, manufacturer data and relevant standards.
Arc flash risk and fault level are closely linked.
Fault level shows how much current could flow during a fault. Arc flash analysis then considers how that fault current, clearing time, equipment arrangement and working distance affect the energy released during an arc flash incident.
If available fault current is misunderstood, the arc flash hazard can also be misunderstood. That can lead to incorrect arc flash boundaries, unsuitable PPE recommendations or missed opportunities to reduce risk.
A combined arc flash and fault level assessment gives duty holders, facilities teams and electrical engineers practical information on fault current, arc flash severity, equipment ratings, protective device performance, PPE requirements and mitigation options.
Arc flash hazards can be caused by a combination of system energy, equipment condition and human interaction.
Common causes and contributing factors include loose connections, damaged equipment, insulation breakdown, equipment failure, human error during operation or maintenance, short circuit faults, earth faults, work near live conductors, poorly maintained switchgear, unsuitable protective devices, high available fault current and slow fault clearing times.
Series arc faults and parallel arc faults are often discussed in relation to arc fault protection devices and arc fault detection devices in low-voltage installations. These devices can help reduce certain electrical fire risks in suitable applications, but they do not replace a full arc flash and fault level assessment for higher-energy commercial or industrial electrical systems.
We can also help with Arc Flash Mitigation to reduce hazards and improve workplace safety.
Covol Engineering provides a structured assessment designed to give you a clear understanding of your electrical system and the risks within it.
Our arc flash and fault level assessment can include site data collection, review of single line diagrams, DB schedules and asset data, modelling in SKM Power Tools, fault current analysis, review of circuit breakers and protective devices, arc flash hazard calculations, incident energy calculations, arc flash boundary assessment, PPE recommendations, arc flash warning labels and a detailed report with practical recommendations.
Where required, we can also provide updated single line diagrams and identify high-risk equipment. If complete electrical records are not available, Covol can advise on the best way to proceed before the assessment begins.
Accurate modelling depends on reliable electrical system data.
During the assessment, Covol may collect and review incoming supply details, transformer data, switchgear ratings, cable sizes and routes, circuit breaker details, protection settings, fuse and relay data, single line diagrams, distribution board schedules, asset data sheets, manufacturer characteristics, electrical loads and existing protection coordination information.
This information allows our engineers to model the electrical installation, calculate fault current, assess arc flash hazards and provide recommendations tailored to your site.
Arc flash risk should be reduced at source wherever possible. PPE is important, but personal protective equipment should not be the only control measure.
Depending on the results of the assessment, Covol may recommend adjusting protection settings, reviewing circuit breaker performance, improving protection coordination, replacing unsuitable electrical equipment, reviewing switchgear condition, reducing incident energy where practicable, improving warning labels, reviewing safety-related work practices and considering arc flash mitigation options for high-risk areas.
The aim is to protect workers, reduce equipment damage and lower the risk of operational disruption.
Covol Engineering has extensive experience delivering arc flash and fault level assessments for industrial and commercial clients across the UK and globally.
Our engineers have completed well over 1,000 studies for major clients in sectors including aerospace, engine production, chemical manufacturing and pharmaceutical manufacturing. We combine detailed electrical engineering knowledge with practical reporting, clear recommendations and a focus on worker safety.
Clients choose Covol because we provide experienced electrical engineers, detailed fault level and arc flash analysis, practical site-specific recommendations, clear assessment reports, warning labels, PPE recommendations, updated single line diagrams where required, and support with arc flash mitigation.
We do not simply produce calculations. We help you understand what the results mean and what action is needed to improve electrical safety.
Learn more about Covol today, and don’t hesitate to get in touch for more expert advice.
If your electrical system has not been assessed, has recently changed, or you are unsure whether existing fault level and arc flash data is accurate, Covol Engineering can help.
Contact Covol Engineering today to discuss your site, electrical documentation and assessment requirements. Our engineers will help identify potential hazards, calculate fault levels, assess arc flash risk and recommend practical steps to protect your people, equipment and operations.
Fault level is calculated by reviewing the power supply, transformer impedance, cable impedance, voltage, earthing arrangement and connected equipment. For commercial and industrial systems, engineers use specialist modelling software to calculate accurate fault current values across the network.
No. An arc fault is the abnormal arcing condition. An arc flash is the release of heat, light, pressure and energy that can result from an arc fault in an electrical system.
Arc flash usually refers to the heat and light produced by an electrical arc. Arc blast refers to the pressure wave and force that can occur when the arc rapidly heats air and vaporises metal. Both can be dangerous during an arc flash incident.
Arc fault detection devices can help detect certain arcing faults in suitable low-voltage installations, particularly where electrical fire risk is a concern. They do not replace a full arc flash and fault level assessment for industrial or commercial electrical systems.
ure wave and force that can occur when the arc rapidly heats air and vaporises metal. Both can be dangerous during an arc flash incident.
Arc flash and fault level assessments are important for organisations operating complex or high-energy electrical systems.
This includes manufacturing sites, chemical and pharmaceutical facilities, aerospace and engineering facilities, power generation and distribution environments, industrial plants, large commercial premises, sites with ageing or modified electrical infrastructure, facilities planning major electrical changes, and organisations reviewing electrical safety or insurance requirements.
An assessment is especially valuable after network modifications, equipment changes, protection setting changes, capacity increases or incidents involving electrical equipment.