Arc-Flash Hazard Arc Flash Overview Tom Studer Eaton Electrical Power Systems Engineering Tempe, AZ Who is Eaton?: Company Overview Electrical Engineering Services What is Arc-Flash?: Definitions / Examples Dangers Costs What Can Be Done?: Engineering Studies & Training A.R.M.S. Arc-Resistant Gear Remote Power Racking 2003 Eaton Corporation. All rights reserved. Who is Eaton $12.3B 2006 Sales Global Diversified Industrial Company Leader in fluid power systems; electrical power quality, distribution and control; automotive engine air management and fuel economy; and intelligent drive train systems for fuel economy and safety in trucks. Business Segments Headquartered in Cleveland, OH Eaton has 60,000 employees and sells products in more than 129 countries. 195 Manufacturing Sites Website: www.eatonelectrical.com NYSE Ticker: etn Eaton PSE s Power Systems Engineers (PSE s) Average 15 years experience with multiple manufacturers equipment/devices (GE, Square D, ABB, AB) Greater than 30% of PSE s with Masters in EE Licensed Professional Engineers Use state of the art Software tools Centralized core group and field deployed resources Active on standards committees and recognized industry power experts Automotive Electrical Fluid Power Truck Engineering Studies Power Quality Studies Harmonic Analysis Transient Analysis Effective Grounding Safety & Reliability Studies Power Quality Site Surveys Arc Flash Studies & Labeling Disturbance Monitoring Protective Device Evaluation Protective Device Coordination Power System Investigations Grounding Short Circuit Power System Audit. As In many more cases, and more the industry excessively addresses high arc arc flash flash incident electrical energies safety We will address the multiple ways to significantly lower arc flash make In Several most cases, real world NFPA examples 70E Hazard will be Risk discussed. Category 2 or lower can be concerns, not be they are discovering high risk associated with what used to incident so normal always all maintenance energy acceptable exposure must to tasks. the by be new process done system with industries. equipment design and de-energized products, -- ABSTRACT obtained retrofits, settings, retro-fills, etc. with the right equipment methods. modifications, alternate protection 1
Standards Covering Arc Flash So National Fire Protection Agency (NFPA) NFPA 70-2008 National Electric Code (NEC). NFPA 70E-2009 Standard for Electrical Safety in the Workplace Occupational Safety and Health Administration (OSHA) OSHA 29 CFR Part 1910 Institute of Electrical and Electronics Engineers (IEEE) C2-2007 National Electric Safety Code (NESC) 1584-2002 Guide for Performing Arc Flash Hazard Calculations. What does each standard have to say about the Arc Flash Hazard?. NEC 2008 Edition Section 110.16 Flash Protection Electrical equipment, such as switchboards, panelboards, industrial control panels, meter socket enclosures, and motor control centers that are in other than dwelling occupancies and are likely to require examination, adjustment, servicing, or maintenance while energized shall be field marked to warn qualified persons of potential electric arc flash hazards. The marking shall be located so as to be clearly visible to qualified persons before examination, adjustment, servicing, or maintenance of the equipment. NEC Arc Flash Label Warning Sign NFPA 70E-2009 NFPA 70E-2009. Article 100. Arc Flash Hazard. A dangerous condition associated with the possible release of energy caused by an electric arc. FPN No. 1: An arc flash hazard may exist when energized electrical conductors or circuit parts are exposed or when they are within equipment in a guarded or enclosed condition, provided a person is interacting with the equipment in such a manner that could cause an electric arc. Under normal operating conditions, enclosed energized equipment that has been properly installed and maintained is not likely to pose an arc flash hazard. FPN No. 2: See Table 130.7(C)(9) for examples of activities that could pose an arc flash hazard. FPN No. 3: See 130.3 for arc flash hazard analysis information. 130.3 Arc Flash Hazard Analysis An arc flash hazard analysis shall determine the Arc Flash Protection Boundary and the personal protective equipment that people within the arc Flash Protection Boundary shall use. 2
Arc Flash Hazard Analysis and Labeling OSHA Code of Federal Regulations. 1910.269(l)(6)(ii) The employer shall train each employee who is exposed to the hazards of flames or electric arcs in the hazards involved. 1910.269(l)(6)(iii) The employer shall ensure that each employee who is exposed to the hazards of flames or electric arcs does not wear clothing that, when exposed to flames or electric arcs, could increase the extent of injury that would be sustained by the employee. 1910.335(a)(1)(i) Employees working in areas where there are potential electrical hazards shall be provided with, and shall use, electrical protective equipment that is appropriate for the specific parts of the body to be protected and for the work to be performed. IEEE C2-2007 (NESC) IEEE 1584-2002. Section 41. Supply and communications systems A. General 1. The employer shall inform each employee working on or about communications equipment or electric supply equipment and the associated lines, of the safety rules governing the employee s conduct while so engaged. When deemed necessary, the employer shall provide a copy of such rules. 2. The employer shall provide training to all employees who work in the vicinity of exposed energized facilities. The training shall include applicable work rules required by this Part and other mandatory referenced standards or rules. The employer shall ensure that each employee has demonstrated proficiency in required tasks. The employer shall provide retraining for any employee who, as a result of routine observance of work practices, is not following work rules. 3. Effective as of January 1, 2009, the employer shall ensure that an assessment is performed to determine potential exposure to an electric arc for employees who work on or near energized parts or equipment. If the assessment determines a potential employee exposure greater than 2 cal/cm 2 exists (see Neal, Bingham, and Doughty [B59]), the employer shall require employees to wear clothing or a clothing system that has an effective arc rating not less than the anticipated level of arc energy.. 1.1 Scope This guide provides techniques for designers and facility operators to apply in determining the arcflash hazard distance and the incident energy to which employees could be exposed during their work on or near electrical equipment. 1.2 Purpose This guide presents methods for the calculation of arc-flash incident energy and arcflash boundaries in three-phase ac systems to which workers may be exposed. It covers the analysis process from field data collection to final results, presents the equations needed to find incident energy and the flash-protection boundary, and discusses software solution alternatives. Applications cover an empirically derived model including enclosed equipment and open lines for voltages from 208 V to 15 kv, and a theoretically derived model applicable for any voltage. Included with the standard are programs with embedded equations, which may be used to determine incident energy and the arc-flash-protection boundary. NFPA 70E 2009 NFPA 70E 2009 NFPA 70E Standard for Electrical Safety in the Workplace 2009 Edition Arc Flash Hazard-Definition A dangerous condition associated with the possible release of energy caused by an electric arc. FPN No. 1: An arc flash hazard may exist when energized electrical conductors or circuit parts are exposed or when they are within equipment in a guarded or enclosed condition, provided a person is INTERACTING with the equipment in such a manner that could cause an electric arc. FPN No. 2: See Table 130.7(C)(9) for examples of activities that could pose an arc flash hazard. FPN No. 3: See 130.3 for arc flash hazard analysis information. Arc Flash Hazard Analysis. A study investigating a worker s potential exposure to arc flash energy, conducted for the purpose of injury prevention and the determination of safe work practices, arc flash protection boundary, and the appropriate levels of PPE. Under normal operating conditions, enclosed energized equipment that has been properly installed and maintained is not likely to pose an arc flash hazard. 3
What is an Arc-Flash? An arc flash starts with an arcing fault. An arcing fault can be defined as the flow of current through a path where it is not intended to flow. The current creates an electric arc plasma and releases dangerous amounts of energy What is an arc-fault? An electric arc is the passage of substantial electrical current through ionized air and gasses. Bolted Fault A B Arc Fault A B Example: NFPA 70E CALCS FOR FLASH PROTECTION BOUNDARY AND INCIDENT ENERGY Bolted Fault Short-Circuit Basics Causes of Bolted Faults Re-energizing without removing temporary grounds Incorrect connection of a parallel run of cables to a motor terminal box Conduit #1 Conduit #2 Motor NFPA 70E CALCS FOR FLASH PROTECTION BOUNDARY AND INCIDENT ENERGY Arcing Fault NFPA 70E CALCS FOR FLASH PROTECTION BOUNDARY AND INCIDENT ENERGY Arcing Fault Faults which are not bolted. Poor electrical connection between conductors can cause arcing. Arcing results in tremendous heat. 35,000 0 F 4
NFPA 70E CALCS FOR FLASH PROTECTION BOUNDARY AND INCIDENT ENERGY Common Causes of Arcing Faults Insulation deterioration and failure Work related incidents when working with tools, removing panels, taking power measurements, etc. Loose connections (cable terminations, transformer connections, etc.) Arc Flash Introduction Numerous workers injured/killed each year while working on energized equipment. Defining incident energy hazards raises awareness of the harm to humans that can result from an electric arc. This includes: Severe skin burns Hearing damage Face and eye injuries Blast pressure injuries DEVELOPMENTS LEADING TO NFPA 70E-2004 Important Temperatures Skin temperature for curable burn 176 0 F Skin temperature causing cell death 205 0 F Ignition of clothing 752 0 F-1472 0 F Burning clothing 1472 0 F Metal droplets from arcing 1832 0 F Surface of sun 9000 0 F Arc terminals 35,000 0 F NFPA 70E-2009 NFPA 70E 2009, Table 130.7(C)(10) PPE Requirements Energy Typical Personal Protective Equipment HRC cal/cm 2 Non-Melting natural fibers such as 100% cotton (fabric weight at least 4.5 oz/yd 0 >0 to 1.2 2 + Safety Glasses & Hearing Protection 1 layer Flame Resistant (FR) clothing, min arc rating of 4 cal/cm 1 >1.2 to 4 2 + Hard hat, safety glasses, Hearing Prot., Faceshield & Hand Prot. 1 layer FR clothing, min arc rating of 8 cal/cm 2 2 >4 to 8 + Hard hat, safety glasses, Face shield, Hearing Prot., Hand Prot. & Foot Prot. (cotton T-shirt is optional, not required) Multilayer of FR clothing, min Arc rating of 25 cal/cm 2 3 >8 to 25 + Flash suit hood, safety glasses, hearing protection, hand & foot protection (cotton T-shirt is optional, not required) Multilayer of FR clothing, min Arc rating of 40 cal/cm 2 4 >25 to 40 + Flash suit hood, safety glasses, hearing protection, hand & foot protection (cotton T-shirt is optional, not required) Undergarments: Must be non meltable fibers such as 100% cotton FR clothing: Shirt and pants. Alternative is coveralls Hand Protection: Leather gloves or Leather protectors over Rubber gloves Foot Protection: Leather Work shoes or boots NFPA 70E Protective Clothing and PPE Table (Table 130.7(C)(10) NFPA ) NFPA 70E Protective Clothing and PPE Table (Table 130.7(C)(10) NFPA ) Hazard/Risk Category Protective Clothing and PPE Hazard/Risk Category Protective Clothing and PPE Hazard/Risk Category 0 - Protective Clothing,Non-melting (According to ASTM F 1506-00) or Untreated Natural Fiber - FR Protective Equipment Hazard/Risk Category 1 - FR Clothing,Minimum Arc Rating of 4 (Note 1) - FR Protective Equipment Shirt (long sleeve) Pants (long Safety glasses or safety goggles (SR) Hearing protection (ear canal inserts) Leather gloves (AN) (Note 2) Arc-rated long-sleeve shirt (Note 3) Arc-rated pants (Note 3) Arc-rated coverall (Note 4) Arc-rated face shield or arc flash suit hood (Note 7) Arc-rated jacket, parka, or rainwear (AN) Hard hat Safety glasses or safety goggles (SR) Hearing protection (ear canal inserts) Leather gloves (AN) (Note 2) Leather work shoes (AN) Hazard/Risk Category 2 - FR Clothing,Minimum Arc Rating of 8 (Note 1) - FR Protective Equipment Hazard/Risk Category 2* - FR Clothing,Minimum Arc Rating of 8 (Note 1) - FR Protective Equipment Arc-rated long-sleeve shirt (Note 5) Arc-rated pants (Note 5) Arc-rated coverall (Note 6) Arc-rated face shield or arc flash suit hood (Note 7) Arc-rated jacket, parka, or rainwear (AN) Hard hat Safety glasses or safety goggles (SR) Hearing protection (ear canal inserts) Leather gloves (AN) (Note 2) Leather work shoes (AN) Arc-rated long-sleeve shirt (Note 5) Arc-rated pants (Note 5) Arc-rated coverall (Note 6) Arc-rated arc flash suit hood (Note 10) Arc-rated jacket, parka, or rainwear (AN) Hard hat Safety glasses or safety goggles (SR) Hearing protection (ear canal inserts) Leather gloves (AN) (Note 2) Leather work shoes (AN) 5
NFPA 70E Protective Clothing and PPE Table (Table 130.7(C)(10) NFPA ) NFPA 70E Protective Clothing and PPE Table (Table 130.7(C)(10) NFPA ) Hazard/Risk Category Protective Clothing and PPE Hazard/Risk Category Protective Clothing and PPE Hazard/Risk Category 3 - FR Clothing,Minimum Arc Rating of 25 (Note 1) Arc-rated long-sleeve shirt (AR) (Note 8) Arc-rated pants (AR) (Note 8) Arc-rated coverall (AR) (Note 8) Arc-rated arc flash suit jacket (AR) (Note 8) Arc-rated arc flash suit pants (AR) (Note 8) Arc-rated arc flash suit hood (Note 8) Arc-rated jacket, parka, or rainwear (AN) Hazard/Risk Category 4 - FR Clothing,Minimum Arc Rating of 40 (Note 1) Arc-rated long-sleeve shirt (AR) (Note 9) Arc-rated pants (AR) (Note 9) Arc-rated coverall (AR) (Note 9) Arc-rated arc flash suit jacket (AR) (Note 9) Arc-rated arc flash suit pants (AR) (Note 9) Arc-rated arc flash suit hood (Note 9) Arc-rated jacket, parka, or rainwear (AN) - FR Protective Equipment Hard hat FR Hard Hat Liner (AR) Safety glasses or safety goggles (SR) Hearing protection (ear canal inserts) Leather gloves (Note 2) Leather work shoes - FR Protective Equipment Hard hat FR Hard Hat Liner (AR) Safety glasses or safety goggles (SR) Hearing protection (ear canal inserts) Leather gloves (Note 2) Leather work shoes NFPA 70E Protective Clothing and PPE Table (Table 130.7(C)(10) NFPA ) Why is an Arc Hazardous? AN = As needed (optional) AR = As required SR = Selection Required Notes: 1. See Table 130.7(C)(11). Arc Rating for a garment or system of garments is express in cal/cm 2. 2. If rubber insulating gloves with leather protectors are required by Table 130.7(C)(9), additional leather or arc-rated gloves are not required. The combination of rubber insulating gloves with leather protectors satisfies the arc flash protection requirement. 3. The FR shirt and pants used for Hazard/Risk Category 1 shall have a minimum arc rating of 4. 4. Alternate is to use FR coveralls (minimum arc rating of 4) instead of FR shirt and FR pants. 5. The FR shirt and pants used for Hazard/Risk Category 2 shall have a minimum arc rating of 8. 6. Alternate is to use FR coveralls (minimum arc rating of 8) instead of FR shirt and FR pants. 7. A face shield with a minimum arc rating of 4 for Hazard/Risk Category 1 or a minimum arc rating of 8 for Hazard/Risk Category 2, with wrap-around guarding to protect not only the face, but also the forehead, ears, and neck (or alternatively, an arc-rated flash suite hood), is required. 8. An alternate is to use a total FR clothing system and hood, which shall have a minimum arc rating of 25 for Hazard/Risk Category 3. 9. The total clothing system consisting of FR shirt and pants and/or FR coveralls and/or arc flash coat and pants and hood shall have a minimum arc rating of 40 for Hazard/Risk Category 4. 10. Alternate is to use a face shield with a minimum arc rating of 8 and a balaclava (sock hood) with a minimum arc rating of 8 and which covers the face, head and neck except for the eye and nose areas. 35,000 F Copper Vapor: Solid to Vapor Expands by 67,000 times Molten Metal Pressure Waves Sound Waves Shrapnel Hot Air-Rapid Expansion Intense Light Courtesy of Cooper Bussmann Bad things can happen. An electric arc fault is a bad thing! Bad things can happen. An electric arc fault is a bad thing! 6
Bad things can happen. An electric arc fault is a bad thing! Large Hydro in Pacific NW 6.9kV Swgr Racking in Breaker AF occurred One worker injured 7+ years, $10+ million Bad things can happen. An electric arc fault is a bad thing! Bad things can happen. An electric arc fault is a bad thing! Bad things can happen. An electric arc fault is a bad thing! Bad things can happen. An electric arc fault is a bad thing! Bad things can happen. An electric arc fault is a bad thing! 7
Arc Flash Injuries Arc Blast Pressure 27,000 F 50 cal/cm 2 165 db < 740 mph 1830 C 2000 psf IR Visible UV Arc Blast Pressure The pressure from an electric arc is developed from two sources: Expansion of the metal as it vaporizes Heating of air by the arc energy When copper vaporizes, it expands by a factor of 67,000. This accounts for the expulsion of nearvaporized droplets of molten metal from the arc (droplets could be propelled up to 10 feet). Arc Blast Pressure Example Inhalation Injuries Inhalation Injuries In addition to burns, an arc flash can cause inhalation injuries. More than a hundred known toxic substances are present in fire smoke. When inhalation injuries are combined with external burns the chance of death can increase significantly. Failed 50kA 5kV available fault current 0.5sec FULL SPEED Toxic Smoke Example DEVELOPMENTS LEADING TO NFPA 70E-2004 Burn Injuries Burns are classified as first, second, or third degree, depending on how deeply the layers of skin (dermis and epidermis) are damaged. 8
DEVELOPMENTS LEADING TO NFPA 70E-2004 Diagram of Normal Skin Epidermis Dermis DEVELOPMENTS LEADING TO NFPA 70E-2004 A First Degree Burn is red and sensitive to touch. There is minimal skin damage and only the skin surface is involved. Example: Sunburn Hypodermis or subcutaneous tissue Muscle DEVELOPMENTS LEADING TO NFPA 70E-2004 A Second Degree Burn involves the first and second layers of skin. The skin reddens intensely and blisters develop. Severe pain and swelling occur and chance for infection is present. DEVELOPMENTS LEADING TO NFPA 70E-2004 A Third Degree Burn causes charring of skin and coagulation of blood vessels just below the skin surface. All three layers of skin are affected. Extensive scarring usually results. DEVELOPMENTS LEADING TO NFPA 70E-2004 What Is a Calorie? A calorie is the energy required to raise one gram of water one degree Celsius at one atmosphere. At 1 second, 1.2 cal/cm 2 of heat energy can cause a second degree burn. DEVELOPMENTS LEADING TO NFPA 70E-2004 The intent of NFPA 70E regarding arc flash is to provide guidelines which will limit injury to the onset of second degree burns. 9
DEVELOPMENTS LEADING TO NFPA 70E-2004 The intent of NFPA 70E regarding arc flash is to provide guidelines which will limit injury to the onset of second degree burns. DEVELOPMENTS LEADING TO NFPA 70E-2004 Definition of Incident Energy IEEE defines incident energy as the amount of energy impressed on a surface, a certain distance from the source, generated during an electrical arc event. Incident energy is measured in calories/cm2 or in Joules/cm2. Three Main Factors Affecting Incident Energy and Arc Flash Skin damage will occur based on the intensity of the heat generated by an electrical arc accident. The heat reaching the skin of the worker is dependent on the following three factors: Main Factors Affecting Arc Flash: Power of the arc at the arc location Distance of the worker to the arc Time duration of the arc exposure DEVELOPMENTS LEADING TO NFPA 70E-2004 The following table shows how the power of the arc and/or time duration of the arc will affect incident energy when the worker distance is held constant at 18 inches from the arc flash. Note: The incident energy calculations were performed using the Arc in a Box equations. Illustration of Power and Time Effects on NFPA Calculations for Arc in a Box Hold Distance Constant Hold time SC constant current at 3 constant cyclesat 30 ka Vary the SC current Vary from the time 16kA from to 50kA 3 to 60 cycles Relatively small Significant change in change terms in of required terms of PPE (~ required 2 cal to PPE ~ 9 (~ 3 cal) to ~ 60 cal) Distance (inches) 18 18 18 18 18 18 18 18 Clearing Time (cyc) 3 6 10 20 30 40 50 60 (sec) 0.05 0.10 0.17 0.33 0.50 0.67 0.83 1.00 SC ka cal/cm 2 cal/cm 2 cal/cm 2 cal/cm 2 cal/cm 2 cal/cm 2 cal/cm 2 cal/cm 2 16 2.07 4.14 6.90 13.81 20.71 27.62 34.52 41.42 18 2.03 4.06 6.76 13.52 20.29 27.05 33.81 40.57 20 2.04 4.08 6.80 13.60 20.40 27.21 34.01 40.81 22 2.11 4.21 7.02 14.05 21.07 28.09 35.11 42.14 24 2.23 4.46 7.43 14.85 22.28 29.71 37.13 44.56 26 2.40 4.81 8.01 16.02 24.04 32.05 40.06 48.07 28 2.63 5.27 8.78 17.56 26.34 35.12 43.90 52.67 30 2.92 5.84 9.73 19.46 29.18 38.91 48.64 58.37 32 3.26 6.52 10.86 21.72 32.58 43.44 54.30 65.16 34 3.65 7.30 12.17 24.35 36.52 48.69 60.86 73.04 36 4.10 8.20 13.67 27.34 41.00 54.67 68.34 82.01 38 4.60 9.21 15.34 30.69 46.03 61.38 76.72 92.07 40 5.16 10.32 17.20 34.41 51.61 68.81 86.02 103.22 42 5.77 11.55 19.24 38.49 57.73 76.98 96.22 115.46 44 6.44 12.88 21.47 42.93 64.40 85.87 107.33 128.80 46 7.16 14.32 23.87 47.74 71.61 95.49 119.36 143.23 48 7.94 15.87 26.46 52.92 79.37 105.83 132.29 158.75 50 8.77 17.54 29.23 58.45 87.68 116.91 146.13 175.36 NFPA 70E CALCS FOR FLASH PROTECTION BOUNDARY AND INCIDENT ENERGY Calculating Prospective Short-Circuit Current, I SC NFPA 70E-2004, Annex D.3 NFPA provides the well known formula that is used to calculate the short-circuit symmetrical amperes from a bolted 3-phase fault at a transformer terminals: I MVA 10 6 Base 100 = 1.732 V % Z SC (4-1) 10
NFPA 70E CALCS FOR FLASH PROTECTION BOUNDARY AND INCIDENT ENERGY Classroom Exercise 4a: Perform a Calculation of Prospective Short Circuit Current Problem: Using equation (4-1), calculate the prospective short circuit current for a fault at the 480 V terminals of a 1500 kva transformer which has a nameplate impedance of 5.5%. 6 1.5 10 100 I SC = 1.732 480 = 32,805 Amps 5.5 Arc-Flash Costs: Human Clothed areas can be burned more severely than exposed skin. The most severe burns are caused by ignited clothing, not by the original flash fire or electric arc exposure. PPE Too Much Not this PPE Not Enough Nor this Accident Description Accident Description Continued Employee performed some troubleshooting on 15KV Gear and determined that he did not have control power Customer was instructed to restore power to the 15KV B side main breaker and remove power from the A side main breaker Employee locked out the A side main breaker and the tie breaker Employee pulled the CPT drawer on the A side main on the front of the switchgear and adjusted the secondary contacts Employee visually inspected the routing of the 15 kv power cables on the A side CPT connections in the rear of the switchgear Customer was instructed to restore power to the A side main and the employee verified the control power was still not present Employee crawled into the lower compartment of vertical section 6 Employee opened the shutter in the VT compartment to see if the 15 kv jumper cables were installed and connected between the CPT and VT drawers When Employees flashlight got too close to the ionized air, there was an arc flash incident 11
Arc Flash Incident Arc Flash Incident Arc Flash Incident Arc Flash Incident Arc Flash Incident Arc Flash Incident 12
Injury Consequences Burn injuries can be fatal. Survival depends on age, health, exposure intensity and time, area of the body burned. Treatment of second degree burns requires weeks, for third degree burns it can be years. The Personal Cost Is Devastating Due to disfigurement and intense pain the victim will often not want to live, depression is common. Children will likely not be able recognize the burn victim after the accident. The victim s spouse will be traumatized, divorce is common. Arc-Flash Costs: Monetary Treating Burn Injury Is Very Expensive National Institute for Occupational Safety and Health (NIOSH) from the US Bureau of Labor Statistics The cost of treatment can exceed $1,000,000 USD for a single case. Treatment can require years of skin grafting and rehabilitation. The victim may never be able to return to work. Arc Flash Example Arc Flash Example Failed 50kA 5kV available fault current 0.5sec FULL SPEED Failed 50kA 5kV available fault current 0.5sec SLOW MOTION 13
Arc Flash Standards and OSHA Six-Point Plan Four separate industry standards concern the prevention of arc flash incidents: OSHA 29 Code of Federal Regulations (CFR) Part 1910 Subpart S. NFPA 70-2008 National Electrical Code. IEEE Standard 1584-2002 Guide for Performing Arc Flash Hazard Calculations. NFPA 70E-2009 Standard for Electrical Safety in the Workplace. Compliance with the latest OSHA standards involves adherence to a six-point plan: A facility must provide, and be able to demonstrate a safety program with defined responsibilities. Calculations for the degree of arc flash hazard. Correct personal protective equipment (PPE) for workers. (FR Rated Clothes, HV Gloves, Face Shield) NIOSH Data for the year 2000 Nonfatal injuries and illnesses = 5.7 million Days away cases = 1.7 million Fatal work related injuries = 5,920 Days away electrical cases = 3,786 Electrical Fatalities = 260 Training for workers on the hazards of arc flash. Appropriate tools for safe working. (Grounds, rubber mats, voltage detectors, hot sticks etc.) Warning labels on equipment. (Arc Flash Labels with Incident Energy (cals) & appropriate PPE) Companies will be cited and fined for not complying with these standards. About 1 of every 450 nonfatal accidents involved electricity, but. 1 of every 23 deaths was caused by electricity. NIOSH Electrical fatalities by industry, 1992-2000. Nonfatal electrical shock and burn injuries involving days away from work 1992-2000 by industry NIOSH s summary & conclusions from these statistics: Electrical accidents are more likely to result in death than many other types of accidents. Contact with overhead power lines is the leading cause of onthe-job electrical death. The construction industry accounted for 45% of electrical deaths followed by: Agriculture (12%); Transportation (11%); Manufacturing (11%); Service (10%). Nonfatal electrical accidents are: distributed more evenly across all industries than are fatalities, but construction industry is still highest. Electrical shock and electrical burns and their distribution varies widely by industry. Arc Flash History Timeline 1968 Dow implements arc flash PPE program 1980 Published article on use of arc flash PPE 1981 Ralph Lee publishes theory for hazard calculations 1986 DuPont implements arc flash PPE program 1990 OSHA subpart S does not address arc flash details 1994 OSHA 1910.269 addresses clothing hazards 1995 DuPont undertakes arc flash R&D 1995 ASTM Arc Test Method development 14
Arc Flash History Timeline 1995 NFPA70E defines arc flash boundary 1996 DuPont arc flash research published 1997 DuPont protective clothing research published 1998 ASTM standards for PPE testing 1999 Arc Flash rated PPE appears 2000 NFPA70E expands arc flash requirements 2002 NEC requires arc flash hazard warning 2002 IEEE 1584 calculation guide published 2004 NFPA 70E major reorganization ARC FLASH Avoidance: Superior Protection with the Right Products What Can Be Done: Engineering Studies: Training Arc Flash Study!...(includes Arc Flash Labels) Protective Device Coordination (Breaker Settings) Short Circuit Study Personal Protective Equipment Arc Flash Reduction Maintenance Switch Arc-Resistant Switchgear & Controls Remote Power Racking NFPA 70E (2009) Key Features Equipment shall be field marked with a label containing the available incident energy or required level of PPE. (130.4(C)) Arc Flash Hazard Analysis shall be updated when a major modification or renovation takes place. (130.3) STANDARDS EESS NFPA70E Arc Flash Compliance Asset Optimization Knowledge Management Integrated Project Solutions Power Systems Engineering Solutions Power Systems Modernization New Equipment Services Field Services Eaton Engineering Services & Systems Arc Flash Studies 70+ Power Systems Engineers Standardized Data Collection Templates Studies, Labels, Training, Recommendations Arc Flash Hazard Analysis shall be reviewed periodically, not to exceed 5 years. (130.3) Hazard Risk Categories (0-4). Changes in PPE; Level 1 PPE includes face shield. (130.7(C)(10)) E-ESS ARC FLASH PROGRAM A calorie is the energy required to raise one gram of water one degree Celsius at one atmosphere. NFPA 70-2005 (NEC) Warning Sign At 1 second duration, 1.2 cal/cm 2 of incident heat energy can cause a second degree burn. E-ESS PROTECTIVE CLOTHING AND PERSONAL PROTECTIVE EQUIPMENT MATRIX Protective Clothing Protective Systems for Hazard/Risk Category & Equipment NFPA 70E Hazard/Risk Category Number 0 1 2 3 4 Range of Arc Rating (cal/cm 2 ) > 0 to 1.2 1.2 to 4 4 to 8 8 to 25 25 to 40 FR Clothing Coveralls (1 layer) Minimum Arc Rating = 8 cal/cm X X X 2 Two Coveralls (2 layer) worn over Minimum Arc Rating (for 2 layers) = 40 cal/cm 2 X X Jacket, parka, or rainwear AN AN AN AN 15
Arc Flash Hazard Analysis and Labeling Arc Flash Hazard Analysis and Labeling NFPA 70E 2009 Annex H Simplified two Category FR Clothing Eaton Recent Arc Flash Study s Categories 0,1 & 2: 8+ Calorie FR long-sleeve shirt 8+ Calorie FR Pants Categories 3 & 4 40+ Cal Jacket 40+ Cal Pants 40+ Cal Hood Gloves, Faceshield/Hood, Hearing Protection Leather Shoes, Safety Glasses, (per hazard level) Cargill 179 Sites Georgia Pacific 54 Sites VA Hospitals 25 Sites Enbridge Pipeline 25 Sites Weyerhaeuser 104 Sites Woodbridge Group 14 Sites GM 12 Sites Ford 10 Sites Eaton Local Arc Flash Study s Arc Flash Incident Asarco Copper Mines Sky Harbor Airport USAA Insurance Group TEP Springerville Wild Horse Pass Casino Chase Field 16
Arc Flash Incident Arc Flash Incident Arc Flash Incident Training Understanding Arc-Flash Existing and Proposed Standards Determining Safe Approach Distance Methods for Calculating Prospective Short Circuit Current IEEE Standard 1584 & NFPA 70E Methods for Calculating Flash Protection Boundary Distance and Incident Energy Value Training Determining Hazard Risk Category Selecting Protective Clothing and the PPE Matrix ATPV Values for Common Types of Garments Practical Methods for Reducing Arc-Flash Hazard Understanding Arc-Flash Eaton can award 0.8 CEUs for the successful completion of this training. Flash Protection Boundary And Limits Of Approach 17
FLASH PROTECTION BOUNDARY AND LIMITS OF APPROACH Approach / Flash Protection Boundaries Definitions of Boundaries and Spaces The closer you approach an exposed, energized conductor or circuit part, the greater the chance of an inadvertent contact and the greater the injury that an arc flash will cause. NFPA 70E- 2004, Annex C NFPA defines approach boundaries and work spaces. The diagram on the next slide illustrates these. FLASH PROTECTION BOUNDARY AND LIMITS OF APPROACH NFPA 70E-2004, Table 130.2(C) NFPA Approach Boundaries to Live Parts for Shock Protection. (All dimensions are distance from live part to employee.) (1) (2) (3) (4) (5) Nominal System Voltage Range, Phase to Phase Limited Approach Boundary 1 Exposed Movable Conductor Exposed Fixed Circuit Part Restricted Approach Boundary 1 ; Includes Inadvertent Movement Adder Prohibited Approach Boundary 1 < 50 Not specified Not specified Not specified Not specified 50 to 300 10 ft 0 in. 3 ft 6 in. Avoid contact Avoid contact 301 to 750 10 ft 0 in. 3 ft 6 in. 1 ft 0 in. 0 ft 1 in. 751 to 15 kv 10 ft 0 in. 5 ft 0 in. 2 ft 2 in. 0 ft 7 in. 15.1 kv to 36 kv 10 ft 0 in. 6 ft 0 in. 2 ft 7 in. 0 ft 10 in. 36.1 kv to 46 kv 10 ft 0 in. 8 ft 0 in. 2 ft 9 in. 1 ft 5 in. 46.1 kv to 72.5 kv 10 ft 0 in. 8 ft 0 in. 3 ft 2 in. 2 ft 1 in. FLASH PROTECTION BOUNDARY AND LIMITS OF APPROACH Qualified Person (OSHA 29CFR1910) (Cont.) Know what precautions to take to work safely, including: how to carry out lockout/tagout procedures how to manage and maintain a safe work area how to use protective grounds Know how to use PPE Know how to use insulating and shielding materials Know how to use insulated tools 1. See definitions in NFPA 70E-2004 Article 100, and text in NFPA 70E-2004 130.2 (D)(2) and Annex C for elaboration. FLASH PROTECTION BOUNDARY AND LIMITS OF APPROACH Qualified Person (OSHA 29CFR1910) (Cont.) Note: A qualified person must be certified by his employer before working on or near energized equipment, (1910.269a2vii) and must have his or her qualifications reviewed annually. (1910.269a2iii) FLASH PROTECTION BOUNDARY AND LIMITS OF APPROACH Work intentionally performed on or near energized equipment or circuits is limited by standards and regulations, such as those issued by OSHA. Only qualified persons may work on energized electric circuits. (1910.333c2) Only qualified persons may perform tests on electric circuits or equipment. (1910.334c1) Only qualified persons may work on or with exposed lines or parts of equipment. (1910.269l1) 18
FLASH PROTECTION BOUNDARY AND LIMITS OF APPROACH PRACTICAL METHODS FOR REDUCING ARC FLASH HAZARDS Only qualified persons may work in areas containing unguarded, uninsulated energized lines or parts of equipment operating at 50 volts or more. (1910.269l1) Live parts to which an employee may be exposed shall be de-energized before the employee works on or near them, unless the employer can demonstrate that de-energizing introduces additional or increased hazards or is infeasible due to equipment design or operational limitations. (1910.333) Minimize Risk with Good Safety Practices De-Energize Equipment versus Working It Live unless increased hazards exist or infeasible due to design or operational limitations. Switching remotely (if possible) Closing and tightening door latches or door bolts before operating a switch. Standing to the side and away as much as possible during switching operations. SOLUTIONS THAT REDUCE ARC FLASH INJURIES and DAMAGE Label Equipment & Train Personnel Minimize Risk with Good Safety Practices Reduce Available Fault Current - if you can maintain fast clearing times Faster Clearing Time Move People Further Away Redirect Blast Energy Prevent Fault PRACTICAL METHODS FOR REDUCING ARC FLASH HAZARDS Minimize Risk with Good Safety Practices Practical Methods for Reducing Arc Flash Hazards Minimize Risk with Good Safety Practices PRACTICAL METHODS FOR REDUCING ARC FLASH HAZARDS Minimize Risk with Good Safety Practices Using the proper tools and equipment (Line side of Main). Bad Exposed Back of Neck Good All of Body Protected 19
PRACTICAL METHODS FOR REDUCING ARC FLASH HAZARDS Minimize Risk with Good Safety Practices Using the proper tools and equipment (Load side of Main). PRACTICAL METHODS FOR REDUCING ARC FLASH HAZARDS Equipment Alternatives Current-Limiting Breakers / Fuses - Reduces the clearing time which reduces the incident energy. Metal-Clad Switchgear - Structural design reduces the possibility of arcing faults within the enclosure. Arc Resistant Switchgear - Structural design includes robust design and pressure relief vents, which redirect the blast away from the worker. ARC FLASH Avoidance: Superior Protection with the Right Products What is PPE? Personal Protective Equipment It is worn by everyone. Police officers, professional athletes, construction workers, chefs and everyone in between. ARC FLASH Avoidance: Superior Protection with the Right Products What is PPE? Hard Hat with Arc Face Shield Rubber Gloves 31 Cal. Arc Suit & Hood F/R Coveralls Electrical PPE ARC FLASH Avoidance: Superior Protection with the Right Products Arc-flash Reduction Maintenance Switch (ARMS) Used to reduce the trip delay of LV circuit breakers while performing maintenance. Enabled with the circuit breaker door closed by a door mounted lockable switch Preserves coordination under normal conditions (not enabled continuously) ARC FLASH Avoidance: Superior Protection with the Right Products ARM TM* s Retrofit for Low Voltage Circuit Breakers Door Mounted Components Breaker Mounted Components Lockout Switch Battery DIGITRIP Harness *Arcflash Reduction Maintenance Switch 20
Practical Methods for Reducing Arc Flash Hazards Multiple Settings Groups Similar to LV maintenance switch, only for MV applications Used to reduce the trip delay of medium-voltage relays while maintenance is being performed on equipment Requires relay with multiple settings groups capability, such as the Cutler-Hammer FP-5000 Medium Voltage ARMS Using FP-5000 Group Settings FP-5000 Relay Indicating Light Switch Reduce Clearing Time Network Protectors FlashGard MCC The Ultimate Arc Fault preventive solution ARC FLASH Avoidance: Superior Protection with the Right Products The FlashGard TM Bucket Unit Latch Internal Shutter Position Open Racking Tool Receiver Closed Bucket Position Connected Test Withdrawn Handle Mechanism FlashGard Motor Control Center Features Specially designed Stab Assembly Designed to fit tightly with the labyrinth vertical bus bar making it virtually arc free 480 Volt Isolation via stab shutter Extendable and Retractable power stabs up to 400 Amp Stab Allows you to engage or disengage the stab with the vertical bus while the door is closed keeping you at a safe distance while performing this operation Device Island Start, Stop, Auto, Man Breaker Starter RotoTractTM assembly No over torque Special screw design spins free at the end of travel in either direction preventing over torque of the mechanism Status Indication Stab position indication Stab shutter position indication 21
FlashGard Door Accessories Remote Racking wired Accessory Accessory to perform RotoTract racking safely behind NFPA Arc Flash boundaries 120 VAC motor driven Mounts to RotoTract Mechanism Wired pendant station for rack-in / rack-out operation. Momentary Jog Mounting offset bracket to clear device panel ARC FLASH Avoidance: Superior Protection with the Right Products How it works Internal Shutter Indicator Open Closed Overrunning mechanism prevents stripping of the mechanism or overtorquing Makes insertion of large size 4,5 buckets a much safer evolution. No more shoving buckets on to the vertical bus. Bucket Position Indicator Connected Test Withdrawn Breaker must be open to access racking tool receiver ARC FLASH Avoidance: Superior Protection with the Right Products Electrical Incidents Motor Control Centers account for the second highest frequency of electrical accidents. As a result of this finding, the industry is in need of a Motor Control Center that addresses all of these potential hazards. MCC s APPLICATIONS Fiber Optic Arc Mitigation Devices Fiber Optic Arc Mitigation Devices Able to Distinguish Between Light from Fault and Background Lighting Fast Acting Relay Trips Breaker Instantaneously European Design (Vaasa, ABB, Etc.) SEL, igard & Eaton APPLICATIONS Fiber Optic Arc Mitigation Devices APPLICATIONS Fiber Optic Arc Mitigation Devices UL Listing Issues NO INDUSTRY STANDARD exists for the design, application, or performance for these systems. On January 27, 2010, Underwriters Laboratories held a meeting to address this issue. UL clearly stated in the January meeting that they do NOT recognize any arc flash detection (light detection) systems. UL Listing Issues Eaton and UL are fully aware that several suppliers of devices that sense internal arcs and operate upstream protective devices have obtained UL labels. These labels, however, have been obtained utilizing generic standards intended for other types of devices, such as protective relays. In essence, they are misleading users relative to the certified capabilities of these devices. Customers need to be aware, that should UL labeled equipment integrated with these devices become involved in accidents that result in damage or injury, the suppliers of these devices will not have a legitimate industry standard upon which to claim safety compliance. 22
APPLICATIONS Fiber Optic Arc Mitigation Devices Safety Related Solution Offerings Other Issues with these Devices Eaton will not utilize these devices to reduce PPE Requirement calculated in an Arc Flash Study. No test standard to justify engineering calculation for arc flash study. Other arc mitigation devices like GE Arc Vault also would have UL issue. Can install in Non-Listed Assemblies May be utilized as a back-up system. Infrared Scanning Windows for LV/MV Assemblies Remote Switching: Chicken Switch Remote Racking of MV Breakers - VCP-W 5/15 kv Swgr New Swgr Without With Remain physically outside the flash protection boundary. Therefore NO ARC FLASH HAZARD protection required! Increase Working Distance Increase Working Distance ARC FLASH Avoidance: Superior Protection with the Right Products Remote Racking VS ARC FLASH Avoidance: Superior Protection with the Right Products Remote Racking Eaton s Universal Design for Retrofit Applications LV or MV Any breaker o Air-Magnetic o Vacuum o Vacuum Replacement o SF6 1-2 high MV & 1-4 high LV Flashgard MCC 23
AmpGard Motor Operated Iso Switch New Optional Accessory For Remote Operation Of Ampgard Isolation Switch And Increased Operator Safety. Motor Operated Iso Switch Temporarily Mounts To Front Of Starter Door Equipped With Mounting Provisions. Operation By Control Station Connected To Motor Operator Via 25- foot Cable. Arc-Resistant Switchgear Redirects Arc Energy and Particulates 5/15 kv Arc Construction Arc Flaps Control Section 2000A or 3000A breaker with Vent VT drawer 1200A can be 1 high or 2 high Manual Close/Open Push Buttons LV Arc Resistant Switchgear - Testing Test @ 65kA / 508V Arc initiated in breaker compartment Plenum Design March 2008 - PASS Substations Without Main Secondaries AFL Retrofit Arc out-gassing through plenum No arc flash out of the front of the gear 24
Substations Without Main Secondaries Pri Fuse Only = 594 Calories Pri Bkr Only= 289 Calories Pri. Bkr + Maint. Switch= 7.5 calories Substations Without Main Secondaries Retrofill Primary Fuse with Mini Vac Bkr Sense at 480V Txmr- Trip Primary Use Group Settings for ARMS Many Variations Must Meet ANSI C37.59 Substations Without Main Secondaries ARC FLASH Avoidance: Superior Protection with the Right Products MV AMPGARD MV VCP-W I/R Windows FlashGard Motor Control Centers Door Mounted Metering and Controls Thru-Door racking capability High Impedance Transformers High Resistance Grounding ASTM F1506 Standard ASTM F1506-02a - Standard Performance Specification for Textile Material for Wearing Apparel for Use by Electrical Workers Exposed to Momentary Electric Arc and Related Thermal Hazards, 2002a Developed to give min performance specs for protective clothing. Major requirement being that the fabric is flame resistant. Results must be reported to the end user as an Arc Rating on a garment label. Definition of Arc Rating Arc Rating Previously the Arc Thermal Performance Exposure Value (ATPV) Minimum incident thermal energy on a fabric or material that results in sufficient heat transfer through the fabric or material to cause the onset of a second degree burn based on the energy transmitted through the clothing. Arc Rating is expressed in cal/cm 2. This energy is related to the Stoll curve. The Arc Rating is an average of 20 tests performed using the ASTM F1959-99 standard. 25
Layering of FR Clothing Layering of FR Clothing Layering of Clothing Layering significantly increases the level of protection. Two thin layers are better than one thick layer. Layer of air acts as a buffer zone between layers of flame resistant fabrics. Some multi-layer testing has been done by various fabric manufacturers and ASTM Task Groups (varies dramatically with different two-ply systems.) Layering of FR Clothing The single layer and multi-layer ratings for two FR fabrics are shown as an example below: Tested per ASTM F1959/F1959M-04 Standard Test Method for Determining the Arc Thermal Performance Value of Materials for Clothing Single-Layer Fabrics Product / Style ATPV INDURA Ultra Soft Fabric Description (cal/cm 2 ) Style 301 7oz (237g/m 2 ) Shirting Twill 8.7 Style 801 13oz (440g/m 2 ) Heavyweight Sateen Multi-Layered Systems 21.0 INDURA Ultra Soft Systems 301-7oz (237g/m 2 ) over 301-7oz (237g/m 2 ) ATPV (cal/cm 2 ) 27.2 801-13oz (440g/m 2 ) Heavyweight Sateen over 301-7oz (237g/m 2 ) 51.5 Wear life & Laundering of FR Clothing Expected Lifetime and Effects of Cleaning Wear life is affected by laundering. Industrial laundering will create more wear on a garment than home laundering. Garments manufacturer s provide the expected lifetime based on use and laundering. FireWear - Inherently flame resistant, a characteristic that cannot be degraded by laundering. Expected wear life of 18 to 30 months when worn and home laundered once per week. Nomex IIIa - Inherently flame resistant, a characteristic that cannot be degraded by laundering. Expected wear life of 30-48 months. Indura Cotton - Cotton fabric made flame resistant through an ammonia cure process. Expected wear life of 12 to 18 months when worn and home laundered once per week. Laundering Instructions for Indura Garments Washing Wash Garments inside out Do not overload washer Use high water level Wash at temperature necessary to clean garment (Maximum 165 F, or 74 C) Use recommended amount of quality detergent. (Phosphate can be used) Laundering Instructions for Indura Garments Washing Do not use chlorine bleach Do not use tallow soap: (One containing animal fats) For optimum results use an acid sour. Softened water provides the best results 26
Laundering Instructions for Indura Garments Drying Dry garments inside out. Do not use extreme heat or leave in for long periods. (Maximum stack temperature 165 F, or 74 C) Remove garment when slightly damp. Complete drying on a hanger. Garments may be line dried. Laundering Instructions for Indura Garments Pressing Press garment to remove wrinkles. Use cotton setting. Specialized Arc Flash Protective Equipment Specialized Arc Flash Protective Equipment Flash Suits / Switching Coats Two-Layer Flash Suit, ATPV = 42 cal/cm 2 Use: Hazard/Risk Category 4 ARC FLASH Avoidance: Superior Protection with the Right Products We do we go from here? 1. Power System Studies Arc Flash Hazard Study Protective Device Coordination Short Circuit Study Updated Plant One-Line Arc-Flash Hazard Labels 2. Power Systems Training Program Understanding Arc-Flash Electrical & Arc-Flash Safety 3. Institute PPE Program 4. Vigilantly enforce Safety & PPE Program.Everyday Thank You! We sincerely thank you for your time! 27