Arc Flash Services
What is Arc Flash?
As defined by the Occupational Safety and Health Administration (OSHA), arc flash is “...a phenomenon where a flashover of electric current leaves its intended path and travels through the air from one conductor to another, or to ground. The results are often violent and when a human is in close proximity to the arc flash, serious injury and even death can occur.”
Arc Flash (also known as an flashover or arcover) is an extremely dangerous event that can happen in any commercial or industrial electrical system. According to the National Fire Protection Association (NFPA) and the Institute of Electrical and Electronics Engineers (IEEE), approximately 2,000 workers are treated for injuries resulting from arc flash every year.
Once an arc flash initiates, it will often travel from a single circuit to the busbars of the panel. This may cause severe physical damage and can significantly impact operations, and ultimately, a firm’s bottom line. As an owner, safety specialist, or even an operational manager, it is critical to understand arc flash, its causes, and the methods to prevent it.
Arc Flash Causes
Human interaction within live panels is the largest cause of arc flash. Specific common triggers include switching on tripped electrical circuits or racking in breakers. However, a misapplied tool or an accidental touch on the wrong surface is all that is required to initiate an arc.
Broken equipment, degraded components, normal wear and tear, contamination, and moisture can all increase the likelihood of arc flash. It is important to be aware of the ways to prevent and mitigate the harm that results from this costly and dangerous phenomenon.
Preventing Arc Flash
Safety by design is the most effective approach to minimizing electrical hazards such as arc flash. Power system studies are critical when considering a new system design. Proper electrical system layout can significantly reduce arc flash hazard risk category (HRC) level. Conveniently, safe design can also improve system reliability, reducing maintenance costs and increasing long-term productivity.
Equipment configuration is the next best way to prevent or reduce arc flash. Knowledge and understanding of an existing electrical system is key for this type of arc flash prevention. Configuration, as part of a larger power system study, is likely to include selective coordination and other mitigation techniques.
It is also important to be able to determine the proper personal protective equipment (PPE) needed for employees when interacting with electrical systems. Although a last line of defense, PPE must be included in an overall electrical risk reduction plan. Even the most robust systems will require some form of PPE and hazard assessment when employees interact with it.
Combining power system studies with proper equipment configuration and electrical safe work practices help mitigate risk to employees and operations. Arc flash studies are the best way to recognize these risks and identify opportunities to reduce potential hazards.
Power System Studies
It is more important than ever to have complete power system studies performed. This is due to arc flash hazard, as well as operational availability and regulatory requirements. Both small and large systems are considered for these studies because of their impact on operations and safety. The typical components of a power system study are short circuit studies, protective device coordination, and arc flash hazard studies.
Short Circuit Studies
Short circuit studies are intended to determine the maximum available fault current at all locations in a power system (e.g., panel boards, busways, and equipment). The National Electric Code (NEC) states: “Short Circuit Current Rating (SCCR) is a rating on components and assemblies representing the maximum level of short-circuit current that a component or assembly can withstand. This rating is used to determine compliance with NEC 110.10. ‘SCCR’ labeling is required on all panels and assemblies.”
A proper short circuit study should take into consideration all sources of fault current and identify the scenario that will supply maximum fault current. Often, in order to identify this scenario, examination of system documentation and design is required. A short circuit study may assist your company in purchasing or designing proper rated, SCCR panels.
Protective Device Coordination
Protective device coordination is meant to ensure proper settings to prevent excessive current in a power system (overcurrent). One of the intentions of coordination is to isolate the smallest section of a power system during a fault. This aims to minimize equipment downtime and strategically isolate electrical incidents.
Arc Flash Studies
Arc flash studies (also known as arc flash analysis or electrical hazard assessment) are a standard component of modern power system analysis. The general purpose of these studies is to identify extreme electrical hazards. It is important to do a full study, as a “partial” arc flash analysis may not cover electrical hazards that lie in small, downstream panels or equipment.
Arc flash analyses are important to determine the hazard that employees may be exposed to. However, they may also help your organization to become compliant with NFPA 70E and OSHA regulations.
Data collection and analysis of engineering drawings are usually the first steps in an arc flash study. From here, engineers or technicians can determine what level of additional field data collection and confirmation will be needed. They will also use specialized software to perform calculations that quantitatively determine incident energy. For more information on performing this calculation, see IEEE 1584.
An arc flash study should also include the necessary labels for equipment and panels. These labels are meant for workers, technicians, and electricians to read and understand known hazards.
An electrical arc flash study along with Electrical Safe Work Practices (ESWP) and training will keep workers safe and companies compliant with NFPA 70E and OSHA.
Current Engineering Arc Flash Services
We specialize in providing continuous arc flash services for a variety of clients in large industrial manufacturing plants where we update and maintain their models daily. We’ve worked on projects in Evansville, Cincinnati and Owensboro, as well as the greater Kentucky, Indiana, and Illinois areas.
Contact us to find out how we can help you with your Arc Flash needs.