Electrical Awareness Arc Flash Overview & Qualifications By: Joseph F. Maida, PE August 18, 2009

1. Electrical Awareness Arc Flash Overview & QualificationsBy:Joseph F. Maida, PEAugust 18, 2009 Fort Washington, PA P 215.542.8700 F 215.542.5652 Orlando, FL P 407.352.3300 F 407.352.3301 Visit us online at www.MaidaEngineering.com

2. Joseph F. Maida, P.E. President Maida Engineering, Inc. • Qualifications: • BSEE – Drexel University – 1971 • MSEE – Drexel University (Power) – 1976 • Licensed Electrical Contractor 1971 -1976 • Officer - US Army Reserve 1971 – 1979 • Delmarva Power & Light Co.1972 – 1974 • Day & Zimmermann, Inc. 1974 -1978 • Maida Engineering, Inc. – 1978 – Present • PE License – PA -1975 (NJ, NY & DE 1976) • PE License – ID, MA, RI, NC, GA, FL, TX, IA, WV, AK and Alberta, Canada • LEED Accredited Professional • PA UCC Review and Advisory Council

3. Why the NEC®? • The National Electrical Code NFPA 70 - NEC® is the least amended model code in the world and no court in the USA has faulted anyone for using the latest version of the NEC®, even when the local code was not updated.1 • 2009 International Building Code has incorporated the 2008 NEC®. • 1. http://en.wikipedia.org/wiki/National_Electrical_Code_(US)

4. NEC® Article 110.16 Flash Protection. • 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.

5. NEC® Article • 110.16 Flash Protection. • FPN No. 1: NFPA 70E-2004, Standard for Electrical Safety in the Workplace, provides assistance in determining severity of potential exposure, planning safe work practices, and selecting personal protective equipment. • FPN No. 2: ANSI Z535.4-1998, Product Safety Signs and Labels, provides guidelines for the design of safety signs and labels for application to products.

6. NEC® Definition • Panelboard. • A single panel or group of panel units designed for assembly in the form of a single panel, including buses and automatic overcurrent devices, and equipped with or without switches for the control of light, heat, or power circuits; designed to be placed in a cabinet or cutout box placed in or against a wall, partition, or other support; and accessible only from the front.

7. NEC® Definition • Switchboard. • A large single panel, frame, or assembly of panels on which are mounted on the face, back, or both, switches, overcurrent and other protective devices, buses, and usually instruments. Switchboards are generally accessible from the rear as well as from the front and are not intended to be installed in cabinets.

8. NEC® Definition • Motor Control Center. • An assembly of one or more enclosed sections having a common power bus and principally containing motor control units. • ARTICLE 312 • Cabinets, Cutout Boxes, and Meter Socket Enclosures • 312.1 Scope. This article covers the installation and construction specifications of cabinets, cutout boxes, and meter socket enclosures.

9. NEC® Article 409.2 • Industrial Control Panel. An assembly of two or more • components consisting of one of the following: • (1) Power circuit components only, such as motor controllers, overload relays, fused disconnect switches, and • circuit breakers • (2) Control circuit components only, such as pushbuttons, • pilot lights, selector switches, timers, switches, control • relays • (3) A combination of power and control circuit components • These components, with associated wiring and terminals, • are mounted on or contained within an enclosure or • mounted on a sub-panel. The industrial control panel does • not include the controlled equipment.

10. NEC® Definition • NFPA 70 National Electrical Code®, 2008 Edition • Qualified Person. One who has skills and knowledge related to the construction and operation of the electrical equipment and installations and has received safety training • to recognize and avoid the hazards involved. • FPN: Refer to NFPA 70E®-2004, Standard for Electrical Safety in the Workplace, for electrical safety training requirements.

11. Qualified Person • NFPA 70 E Standard for Electrical Safety in the Workplace, 2009 Edition • Qualified Person. A qualified person shall be: • Trained and knowledgeable of the construction and operation of equipment or a specific work method • Trained to recognize and avoid the electrical hazards that might be present with respect to that equipment or work method.

12. Qualified Person • NFPA 70 E Standard for Electrical Safety in the Workplace, 2009 Edition • Qualified persons shall be familiar with the proper use of: • The special precautionary techniques, • Personal Protective Equipment, including Arc-flash, Insulating and Shielding materials, Insulated tools and test equipment.

13. Qualified Person • NFPA 70 E Standard for Electrical Safety in the Workplace, 2009 Edition • A person can be considered qualified with respect to certain equipment and methods but still be unqualified for others.

14. What is an Arc Flash? Question What is an arc flash?

15. Arc Flash • NFPA 70 E Standard for Electrical Safety in the Workplace, 2009 Edition – Appendix K Arc-Flash - When an electric current passes through air between ungrounded conductors or between ungrounded conductors and grounded conductors. Exposure to these extreme temperatures both burns the skin directly and causes ignition of clothing, which adds to the burn injury. Arc-flashes can and do kill at distances of 3 m (10 ft).

16. What is an Arc Flash? • Arc-Flashes occurs when electricity flows through air between two (2) parts of a power circuit which are not at the same voltage. The parts could be two (2) conductors of different phases or a phase conductor and ground when the system is grounded. • Arc flashes are more likely to occur where dust or humidity are present or after an initial electrical short • because the vaporized particles provide low impedance • media for current to flow between the phases or to • ground. • Circuit breakers can explode if subjected to short circuit currents higher than their rating.

17. What is an Arc Flash? • Electricity can flow through any medium but cannot flow through a vacuum. Insulated materials present a significantly high impedance but will conduct more electricity as the voltage increases. • The majority of hospital admissions due to electrical accidents are from arc-flash burns. • Each year more than 2,000 people are admitted to burn centers with severe arc-flash burns. Almost 5 people every day. • Hazards are shown on the following slide.

18. What is an Arc Flash? Flame Retardant Clothing Provides added protection from arc flash burns only! ----------------------------------------------------------- Electrical hazards are shown on the following slide.

19. What is an Arc Flash?

20. Electric Hazards • Electric Shock – Electricity, resulting from • electromagnetism, passing through the body can • cause shock, cardiac arrest and internal burns. • Arc-Flash Burns – Caused by air that can reach • 35,000° F. Hotter than the sun! Hot enough to vaporize • metal. • Arc-Flash Blasts – Pressure waves that will throw a person away from the blast into walls and other equipment or off ladders and platforms.

21. Electric Hazards • Intense Light – Electric arcs can create light that will • damage eyes and may cause cataracts years later. • Sound Waves – Noise levels that can cause temporary • or permanent loss of hearing • Projectiles – Molten pieces of metal, vapors and • shrapnel that can penetrate flame retardant clothing.

22. Why now and not before? Question Why now and not before?

23. Why now and not before? • Electrical power distribution system are being designed • to generate and distribute more electrical energy. • Personnel are more often exposed to recognized electrical hazards that could cause death or serious physical harm when “examining, adjusting, servicing, or maintaining electrical equipment”. • Understanding of the arc flash hazards has increased • Personal Protective Equipment (PPE) to prevent death or severe injuries due to arc flash burns are available.

24. Why now and not before? • In the early 1980’s, Dupont developed flame retardant material (Nomex). • Ralph Lee, a Dupont Consultant, looking for uses for the new flame retardant material, performed tests to determine the effect “heat” from an electric arc flash would have on human skin. • Ralph Lee developed the first set empirical equations \ that could be used to calculate “incident energy” associated with an arc flash. The equations are still used for electrical power systems rated above 15,000 Volts.

25. Why now and not before? • Ralph Lee’s work showed that skin temperatures above 96°C for .1 seconds or 6 cycles would result in incurable 3rd degree burns and that at a temperature of 80°C the skin would be just curable or sustain a 2nd degree burn. • In 1998, Dougherty, Neill and Floyd developed the first Equations which considered the effect of an arc in a box versus an arc in open air. They developed the Arc Hazard Classifications for flame retardant clothing. Their equations are only for systems rated below 1,000 volts with short circuit currents between 16,000 and 50,000 amps. Equations are no longer utilized.

26. Why now and not before? • An IEEE industry group sponsored by petroleum and chemical industries developed the latest formulas that are published in the IEEE Standard 1584 - 2002 Guide for Performing Arc Flash Calculations. It contains: • Empirical formulas, derived from tests that can be used for 3Ø power systems up to 15,000 volts and for short circuit currents between 700 and 106,000 amps. • Generally, no need for calculation on systems rated at 50 volts or less and on systems rated 240 volt and less that are derived from transformers rated less than 125 KVA. The guide does not state if this rating is for 1Ø and 3Ø transformers.

27. Why now and not before? • IEEE Standard 1584 - 2002 Guide for Performing Arc Flash Calculations contains equations to calculate Arc Flash Incident Energy based on: • The short circuit current and duration of an arc that consider if the arc occurs within a box or in open air and if the power system is grounded or ungrounded. • The short circuit current and the type of fuse or circuit breaker, if the arc flash current will trip the circuit breaker or blow the fuse. • Incident Energy is the amount of energy impressed on a surface a certain distance from the source.

28. Why now and not before? • Occupational Safety and Health Administration (OSHA) was created in 1971. • OSHA has worked with employers and employees to provide a better working environment and since its creation, has helped to cut workplace fatalities by more than 60 percent and occupational injury and illness rates by 40 percent while employment in the United States has doubled.1 • OSHA is part of the US Department of Labor. • OSHA regulations are written under Title 29 of the Code of Federal Regulations 1. http://www.osha.gov/as/opa/oshafacts.html

29. Why now and not before? • On January 16, 1981, OSHA by reference incorporated the relevant requirements from Part 1 of then new NFPA 70E -1979 as its electrical standard for general industry. • The first substantial changes to NFPA 70E were introduced in 1995 and included a consensus standard on work practices and PPE application based on theoretical modeling developed by Ralph Lee. • Subpart S of 29 CFR Part 1910 was updated on August 13, 2007 to reference NFPA 70E – 2000 and NFPA 70 – 2002.

30. Why now and not before? • Calculations: • Methods and Empirical Equations Developed by - Ralph Lee - 1981 • - IEEE Group (1584) – 2002 • Charts: • Published within NFPA 70E – 2004 • Calculators • Provided with IEEE 1584 – 2002 • Computer Software • Developed by SKM Systems Inc. and others

31. Why now and not before? • Calculation - IEEE Group (1584) – 2002 • Empirical Formulas that consider for many variables including short circuit current and time of exposure. • Formulas specific to types of fuses. • General Formulas that are based on fuse or breaker sizes and available short circuit current. • Defines when calculations are not required. • Refers to Lee’s equations for systems greater than 15,000 Volts.

32. Why adhere to NFPA 70 E Question Why adhere to NFPA 70E Article 130 - “Working on or near live parts “?

33. Why adhere to NFPA 70 E OSHA Non-mandatory Compliance Guidelines for Hazard Assessment and Personal Protective EquipmentSelection. - 1910 Subpart I App B Electrical Codes NFPA 70 National Electrical Code®, 2008 Edition NFPA 70E Standard for Electrical Safety in the Workplace, 2009 Edition

34. Why adhere to NFPA 70 E? • With the addition of Article 110.16 in the 2002 National Electrical Code (NEC®), employers and employees have become aware of “electric arc flash hazard”. • With the publication of NFPA 70E Standard for Electrical Safety in the Workplace, 2009 Edition, employers and employees have methods to safeguard employees from at least one of the “electric arc flash hazards”. • 1: NFPA 70E Standard for Electrical Safety in the Workplace, 2004 Edition

35. Why adhere to NFPA 70 E?

36. January 9, 2002 Conclusion: • Though OSHA does not, per se, enforce NFPA 70E Standard, 2000 Edition, OSHA considers the NFPA Standard a recognized industry practice. • The employer is required to conduct hazard assessment in accordance with 29 CR 1910.132(d)(1). • If a arc flash hazard is present, or likely to be present, then the employer must select and require the employees to use the selected apparel.

37. January 9, 2002 • Employers who conduct the hazard/risk assessment, and select and require their employees to use protective clothing and other PPE appropriate for the task, as stated in NFPA 70E 2000 edition, are deemed in compliance with the Hazard Assessment and Equipment Selection OSHA Standard U. S. Department of Labor – Jan. 9, 2002

38. OSHA • OSHA commonly uses the “General Duty Clause”, which is paraphrased below or as an alternate usesNFPA 70E or the NEC for citations related to arc flash incidents. • General Duty Clause: • Section 5(a)(1) of the Occupational Safety and Health Act requires an employer to furnish to its employees “employment and a place of employment which are free from recognized hazards that are causing or are likely to cause death or serious physical harm to his employees”.

39. Why adhere to NFPA 70 E Answer It is the right thing to do!

41. Arc Flash Labels Question What is and where are Arc Flash Label Required?

42. Arc Flash Labels • Arc Flash labels are required on equipment “such as” panelboards, switchboards, motor control centers, industrial control panels and meter sockets, • Arc Flash labels are required on motor starters, variable frequency drives, plug-in bus duct, equipment control panels and building management panels if they contain equipment that is 50 volts or higher and are “likely to require examination, adjustment, servicing or maintenance while energized”.

43. Arc Flash Hazard Labels • The following arc flash label would suffice in meeting the • requirements of NEC Article 110.16 but may not suffice • in meeting NFPA 70E – 2009. • Equipment Labeling. Equipment shall be field marked • with a label containing the available incident energy • or required level of PPE. • 1. NFPA 70E 2009

44. Arc Flash Hazard Labels • Arc flash labels can contain other information that can be provided by the owner or employer to the employee when needed based on the system configuration at the time

45. Arc Flash Hazard Labels • Limited Approach: The closest distance an unqualified person can approach unless made aware of the danger and accompanied by a qualified person. • Restricted Approach: The closet distance a qualified person can approach with proper PPE and tools. • Prohibited Approach: The minimum distance to prevent flashover and arcing. • Flash Protection Boundary: The distance where the energy from the arc will not cause a 3rd degree burn to unprotected skin.

46. Arc Flash Hazard Labels

47. Shock Hazard Analysis Electric Shock Hazard Analysis • The following chart is the basis for determining electric shock boundaries. It is contained within NFPA 70 E 2009. • The actual chart covers voltage as high as 800,000 volts.

48. Shock Hazard Analysis Table 130.2(C) Approach Boundaries to Energized Electrical Conductors or Circuit Parts for Shock Protection (All dimensions are distance from energized electrical conductor or circuit part to employee Limited Approach BoundaryRestricted Approach Nominal System Exposed Exposed Boundary; Includes Prohibited Voltage Range, Movable Fixed Inadvertent Movement Approach Phase to Phase Conductor Circuit Part Adder Boundary Less than 50 Not specified Not specified Not specified Not specified 50 to 30010 ft 0 in. 3 ft 6 inAvoid contactAvoid contact 301 to 75010 ft 0 in. 3 ft 6 in.1 ft 0 in. 1 in. 751 to 15 kV10 ft 0 in. 5 ft 0 in. 2 ft 2 in. 7 in. 15.1 kV to 36 kV 10 ft 0 in. 6 ft 0 in. 2 ft 7 in. 10 in.

49. Arc Flash Hazard Analysis Arc Flash Hazard Analysis are performed to determine the Arc Flash Hazard Category And Arc Flash Protection Boundary

50. Arc Flash Labels • 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.1 • The Arc Flash Protection Boundary is the distance at which a person is likely to receive a second-degree burn. • All parts of the body inside the Arc Flash Protection Boundary shall be protected.1 1. NFPA 70E -2009