Arc Flash & Electrical Compliance Consultants
An Arc Flash is any event in your electrical system that generates an unwanted and unexpected release of energy. This arc flash will cause significant damage to your equipment and severely injure your employees.
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What is an Arc Flash?
An Arc Flash is any event in your electrical system that generates an unwanted and unexpected release of energy. This energy release can be as small as a flash of light with a popping sound to a major fireball explosion that sounds like a howitzer being fired. The concern is that energy released above a certain level will ignite non flame resistant clothing and cause major flesh burns to a person.
These conditions can put your employees in the burn ward or cause instant death. Arc Flash events can also cause significant damage to equipment and often “shut down” a facility or a portion of a facility while costly repairs and additional maintenance are completed.
During these events, electrons travel at the speed of light in the magnitude of thousands of amps. If your electrical system is of any size at all, then it can generate enough energy during an Arc Flash to generate the following conditions:
• Blinding light to the eye
• Thermal heat 4 times that of the sun (35,000 degrees F)
• 2nd, 3rd, or 4th degree burns to unprotected skin
• Sound at levels that could rupture ear drums
• Molten metal that can splatter and burn into skin tissue
• A toxic vapor cloud that can be inhaled into the lungs
• Flying metal parts launched in all directions
• A pressure wave that will knock you down
What causes an Arc Flash?
Arcing faults cause arc flash incidents. Basically, anything that “shorts” a circuit and causes current to travel out of its normal path can set off an arc flash. Simply stated, the separation or “space” around and between energized components is compromised and the current actually flows through the ionized air causing an arc. This arcing fault releases energy out into the surrounding environment that can be devastating to employees and equipment. Typically, one of the causes below is attributable to starting an arc flash incident.
• Accidental contact by a worker or tool while working on energized equipment
• Mechanical breakdown, loose connections, and insulation failure – could be caused by unfinished or inadequate maintenance
• Dust build up between conductors
• Animals contacting energized components
• Current overload
• Voltage transients
What is an Arc Flash Hazard Analysis?
The only way to know how severe arc flash events will be at your facility is to conduct an Arc Flash Hazard Analysis. This analysis calculates the incident energy generated during an electrical arc event using the magnitude and potential time duration of these events at various electrical devices in your system. The end goal is to determine the Flash Protection Boundary and appropriate personal protective equipment (PPE) that people within the Flash Protection Boundary shall use.
The Flash Hazard Analysis requires the following items to be completed:
Collection of necessary electrical data for system modeling including:
• Available energy levels coming into the plant from electrical utility service
• Wire sizes and lengths
• Distribution equipment types and ratings
• Overcurrent protection device information (manufacturer, size, and trip settings)
• Transformer ratings and impedances
Engineering analysis to determine the incident energy and Flash Protection Boundary. This includes:
• Entering all necessary electrical system data into a professional engineering modeling program
• Determining the available fault current and time it takes the overcurrrent protection device to clear the fault at each applicable electric panel
• Creating one-line diagrams
• Calculation of energy released (incident energy) during an arc flash event
Based on the arc flash information provided by the engineering analysis, a Hazard/Risk Category (HRC), per the NFPA 70E guideline, is determined for each applicable location. PPE requirements for workers can then be established once the HRC is known for each panel location.