Arc flash hazard assessments are becoming more common across UK industrial and commercial sites, driven by increasing awareness of the risks associated with electrical systems and a clearer understanding of the regulatory framework that requires employers to manage those risks. The assessment is the necessary starting point. What follows it, and how well it is done, determines whether the findings translate into genuine improvements in electrical safety or remain as a document filed after the event.
Arc Flash Mitigation is the process that bridges the gap between identifying an arc flash risk and actually reducing it. Covol Engineering, based in Billingham and working with industrial and commercial clients across the UK and globally, provides specialist arc flash mitigation services that build on assessment findings and develop practical, engineering-led solutions for the specific electrical systems involved.
What an Arc Flash Event Actually Involves
An arc flash is the result of an electrical current jumping a gap between two conductors and releasing a sudden, violent burst of energy. The energy released can include intense heat to thousands of degrees, a pressure wave, a blinding flash of light and molten metal particles. People working in proximity to electrical equipment when an arc flash occurs face the risk of severe burns, blast injury, hearing damage, and eye injury, even when wearing personal protective equipment.
The severity of an arc flash event depends on the amount of energy available at the point of the fault and how quickly the protective devices in the system clear the fault. Incident energy is the measure used to quantify this, expressed in calories per centimetre squared. Higher incident energy means greater severity and more demanding PPE requirements for anyone working on or near the affected equipment.
Why PPE Alone Is Not Sufficient
Personal protective equipment has an essential role in arc flash safety, but it is a last line of defence rather than a primary control. Appropriate PPE, correctly specified for the incident energy levels identified in the assessment, protects workers when an arc flash event occurs. It does not reduce the probability of the event happening or reduce the energy released when it does.
Engineering controls address the problem more fundamentally. The mitigation measures that Covol considers for specific systems include:
- Upgrading or adjusting circuit breakers to reduce fault clearing time, which directly reduces incident energy
- Installing current transformers and motor control centres designed for arc flash protection
- Using maintenance mode settings that limit available fault energy when maintenance work is being carried out
- Designing fault current reduction devices into the electrical system
- Improving insulation within the electrical system to reduce the risk of fault initiation
The right combination of measures depends on the electrical system being assessed, the fault current levels present, the incident energy calculations from the assessment, and the operational requirements of the site. There is no single solution that applies across all systems, which is why the assessment and the mitigation need to be treated as a connected process rather than separate activities.
The Relationship Between Assessment and Mitigation
An arc flash and fault level assessment identifies where arc flash hazards exist, calculates incident energy at each relevant point in the electrical system, and establishes the conditions under which a fault could occur. That information is the foundation on which mitigation is built.
Once Covol has the assessment findings, the engineering team can identify which areas present the highest risk, determine where engineering controls would produce the most significant reduction in incident energy, and develop a prioritised mitigation plan that fits around the operational requirements and shutdown schedule of the site. Where shutdown arrangements limit what can be done in a single outage, the mitigation approach accounts for this rather than assuming unrestricted access.
The assessment and mitigation cycle should also be revisited when significant changes are made to the electrical system. Changes in fault current from the distribution network, new equipment being added, modifications to protection settings, or changes in operating configuration can all affect incident energy levels identified in a previous study.
Awareness Training as Part of the Programme
Technical mitigation reduces arc flash risk at the system level. Awareness training ensures that the people working on or near electrical equipment understand the hazards they face, the significance of arc flash labels and incident energy levels, and the safety procedures and PPE requirements that apply to their work. Covol provides arc flash awareness training alongside assessment and mitigation services, which means the technical and human elements of an arc flash safety programme can be developed together rather than in isolation.
