1. What is an arc flash5 min. Video arc flash5 min. What causes an arc flash10 min. Video PPE15 min. PPE demo10 min Flash hazard15 min. ***Flash hazard analysis ***Flash protection boundary ______ 60 min.

2. An Arc flash is essentially a bolt of lightning that occurs around energized electrical equipment. It can occur spontaneously and is often triggered simply by the movement of air when an electrical enclosure is opened. Every person who has worked around energized electrical equipment is familiar with arc flash – most have seen it first hand. But it is kind of like a major automobile accident: No one really expects it to happen to them, so people have a tendency to drive with significantly less caution than they should.

3. So it is with arc flash, only worse. Similar to driving, you can make a mistake, or you can be doing everything right when someone slams into you. Specifically, what is an arc flash? An arc flash is electric current flowing through an arc outside its normal path where air becomes the conductor of high thermal energy (more than 5,000 degrees Celsius) and generates highly conductive plasma. Arc flash will conduct all available energy and generate an explosive volumetric increase of gases which blows electrical system doors off and potentially generates shrapnel.

4. Arc Flash Accident - live cam.

5. Accidental contact with energized parts Inadequate short circuit ratings Tracking across insulation surfaces Tools dropped on energized parts Wiring errors Contamination, such as dust on insulating surfaces Corrosion of equipment parts and contacts Improper work procedures The vast majority of arc faults occur when the door is open or being opened.

6. An arc faults happens when electric current flows through air gaps between conductors. Insulation failure and accidents caused by touching a test probe to the wrong surface or slipped tool are the most common causes of an arcing fault. The fault current magnetic fields make conductors to separate producing an arc. In other words, arc flash is caused by uncontrolled conduction of electrical current from phase to ground, phase to neutral, and/or phase to phase accompanied by ionization of the surrounding air. Because of the expansive vaporization of conductive metal, a line- to-line or line-to-ground arcing fault can escalate into a three phase arcing fault in less than a 1/1000 of a second. The heat energy and intense light at the point of the arc is called arc flash.

7. Short circuits and arc faults are extremely dangerous and potentially fatal to personnel. The product of arc fault current and voltage concentrated in one place, results in enormous energy released in several forms. Arc fault generates large amounts of heat that can severely burn human skin and set clothing on fire. Temperatures at the arc can reach four times the temperature of the sun's surface. The high arc temperature vaporizes the conductors in an explosive change in state from solid to vapor. Copper vapor expands to 67,000 times the volume of solid copper. Conductive vapors help sustain the arc and the duration of the arc is primarily determined by the time it takes for over current protective devices to open the circuit. For example, fast acting fuses may open the circuit in 8 ms or faster while other devices may take much longer to operate and open. Metal is blasted and splattered from the fault location. The arcing faults also produce large shock waves that can blow personnel off their feet. The other exposure risks to arcing faults include flying debris, severe sound waves, shock hazard due to touching energized conductors etc.

8. Arc Flash Demo

10. Note: 1.Electrical equipment and circuit wiring are considered energized unless placed in an electrically safe work condition such as locked, tagged, tried, tested and grounded. 2.Standard PPE (i.e. Hard Hat, FRC, Safety Glasses and Safety Shoes) is required for all electrical work. 3.PPE requirement (i.e. UV face shield) is based on the assumption that work is performed within the arc-flash boundary. 4.Voltage rated gloves with leather protectors are required for all energized work / voltage testing.

13. A dangerous condition associated with the release of energy caused by an electric arc. Arc flash incidents involving workers who are not properly protected results in more than 2000 workers being admitted to burn centers each year. The best protection from the arc flash hazard is to establish an electrically safe work condition. If that is not feasible, the alternative is to conduct a flash hazard analysis according to a published safety procedure, then wear appropriate FR clothing.

14. A study investigating a workers potential exposure to arc- flash energy, conducted for the purpose of injury prevention and the determination of safe work practices and the appropriate levels of PPE. An arc occurs when an insulating medium such as air breached by a conducting component. An arc flash, defined as the energy released during an arcing fault, occurs when current flows through a medium that is not intended to conduct electrical current. Because the arc current is not intended, the arc current releases energy that also in not intended, thus exposing a worker to unexpected hazards

15. A flash hazard analysis must consider the possibility that an arcing fault might occur. If an arcing fault occurs, workers are exposed to unexpected conditions. The flash hazard analysis must determine the degree of the hazards associated with the unintended conditions. In an arc flash event, electrical energy is converted to other forms. The other forms of energy include heat, pressure, IR, UV, visible light, and energy at other electromagnetic frequencies. As currently practiced, however, the flash hazard analysis considers only exposure to thermal energy. The analysis must determine the amount of thermal energy to enable a worker to select appropriate PPE.

16. An approach limit at a distance from exposed live parts within which a person could receive a second degree burn if an electrical arc flash were to occur. The flash protection boundary id the first issue to be defined in a flash hazard analysis, the Flash Protection Boundary defines the point at which FR protection is necessary to avoid a second-degree burn. Any of all body parts of a worker are required to be protected. If a workers hand and arm are within the Flash Protection Boundary, the hand and arm must be protected from the thermal hazard. If a workers head is within the Flash Protection Boundary, the workers head must be protected from the thermal hazard.

17. A complete Fr clothing and equipment system that covers the entire body, except for the hands and feet. This includes pants, jacket, and bee-keeper –type hood fitted with a face shield. The personal protective equipment industry has experienced a dramatic evolution of protective schemes and equipment for workers. During this time, the term flash suit has not been used consistently throughout the industry. This definition clarifies the specific components that comprise a flash suit and points out that a face shield may not be used when a flash suit is required.

18. Does a shock hazard exist? Will the worker be exposed to the shock hazard at any point during the work task? What is the degree of the hazard? What protective equipment is necessary to minimize the exposure? Does an arc flash hazard exist? Will the worker be exposed to a thermal hazard at any point during the work task What is the degree of the arc flash hazard? Both a shock analysis and an arc flash analysis are required before any person is permitted to approach the exposed live part. There analysis must answer the following questions:

19. What protective equipment is necessary to minimize exposure to the thermal hazard? Does a co-occupancy hazard exist? What measures will be taken to minimize the impact of other work? Will other workers be exposed to an electrical hazard because of the work task? Will the worker be exposed to any other electrical hazard while executing the work task? What authorization is necessary to justify executing the work task while the exposed conductor/s is/are energized?

20. Qualified workers who are permitted to work on or near exposed energized conductors of circuit parts must select and use work practices that provide protection from shock, arc flash, and other electrical hazards. The work practices that are used must minimize any potential for injury. For instance, body position is one factor that a qualified person should recognize as an element of the analysis that could reduce exposure to electrical shock or arc flash. The hazard / risk analysis must determine whether any conductor will remain energized for the duration of the work task. The analysis must determine the shock approach boundaries and the Flash Protection Boundary.