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  • 1. Arc Flash Energy & Protection Presented by EWB Engineering (Electrical Engineers)
  • 2. Objective To Understand • What is An Arc Flash • Why OSHA Is Addressing This Issue • New Requirements In NEC & NFPA 70E • Impact to Industry • Steps in Performing an Arc Flash Analysis • How to Select Required Protective Clothing
  • 3. Arc Flash Event Every Day An Electrician Is Severely Injured by an Arc Flash Event
  • 4. What Is An Arc Flash An Arc Flash is a Sudden Release of Heat and Energy Caused By An Electric Arc Arc Resistant Switchgear Undergoing Test For an Arcing Fault
  • 5. Recent Changes • • • • • • Attention to Personnel Protection (PPE) Recognition of Unsafe Work Practices Impact to Business and Medical Costs Changes to NFPA 70E & NEC IEEE Standard for Arc Flash Analysis Requirements of OSHA 1910, Subpart S
  • 6. What Does OSHA Say? • 29 CFR 1910.333 – Live electrical parts that an employee may be exposed shall be de-energized unless additional or greater hazards are introduced. • 29 CFR 1910.335 – Employees working in areas where potential electrical hazards exist shall be provided with and shall use personal protective equipment.
  • 7. What Does NFPA 70E Say? • NFPA 70E, Part II, 2-1.3.3 “A flash hazard analysis shall be done before a person approaches any exposed electrical conductor or circuit part that has not been placed in an electrically safe work condition.”
  • 8. What Does National Electric Code (NEC) Say? • NEC 110.16 States Equipment must be marked to warn qualified persons of potential electrical arc flash hazards.
  • 9. Results of Arc Flash Analysis • Flash Protection Boundary • Incident Arc Energy • Hazard Level for PPE
  • 10. Arc Flash Principles  Radiated Energy From Flash  Radiated Energy Function of  Arc Power  Distance From Arc AC Volts  Time to Extinguish Arc  Arc Power Function of  Arc Voltage & Arc Current  Arc Voltage Function of  Arc Gap
  • 11. Incident Arc Energy The amount of energy impressed on a surface, a certain distance from the source, generated during an arc event.
  • 12. Arc Flash Boundary A distance from exposed live parts within which a person could receive a second degree burn.
  • 13. Determine PPE Hazard Level Category Cal / cm2 FR Clothing 0 1.2 Untreated Cotton 1 5 FR Shirt & FR Pants 2 8 Cotton Underwear + FR Shirt & FR Pants 3 25 Cotton Underwear + FR Shirt & FR Pants + FR Coverall 4 40 Cotton Underwear + FR Shirt & FR Pants + Double Layer Switching Coat & Pants
  • 14. Calculation Methods • IEEE 1584 – IEEE Method Preferred • NFPA 70E Tables – Can Be Used if Calculations Not Available – Limited Range of Fault Currents and Protective Device Characteristics
  • 15. PPE Clothing Requirements • Employees Required to Wear Flame Resistant (FR) Clothing – PPE • The Required Level of Clothing and Personal Protection Depends on the – Calculated Incident Arc Energy For – The Specific Task
  • 16. Arc Flash PPE Categories • • • • • Category 0 Untreated Cotton (Long Sleeve) Untreated Cotton Pants (Long) Voltage Rated Gloves Safety Glasses Hard Hat • • • • • • Category 1 FR Long Sleeve Shirt Untreated Cotton Pants (Long) FR Pants (Long) Safety Glasses Voltage Rated Gloves Hard Hat
  • 17. Arc Flash PPE Categories Category 2 • Untreated Cotton T-Shirt • Untreated Cotton Shirt (Long Sleeve) • FR Shirt (Long Sleeve) • Untreated Cotton Pants (Long) • FR Pants (Long) • Safety Glasses • Voltage Rated Gloves • Hard Hat • Double Layer Bee Keepers Hood
  • 18. Arc Flash PPE Categories Category 3 • Untreated Cotton T-Shirt • Untreated Cotton Shirt (Long Sleeve) • FR Shirt (Long Sleeve) • Untreated Cotton Pants (Long) • FR Pants (Long) • Voltage Rated Gloves • Safety Glasses • FR Hard Hat Liner • Hard Hat • Double Layer Bee Keepers Hood • Hearing Protection
  • 19. Arc Flash PPE Categories Category 4 • • • • • • • • • • • • Untreated Cotton T-Shirt Untreated Cotton Shirt (Long Sleeve) FR Shirt (Long Sleeve) Untreated Cotton Pants (Long) FR Pants (Long) FR Coveralls Voltage Rated Gloves Safety Glasses FR Hard Hat Liner Hard Hat Double Layer Bee Keepers Hood Hearing Protection
  • 20. Conclusions • OSHA & NFPA 70E Require An Arc Flash Hazard Analysis For Proper PPE • New Requirement in NEC States That Arc Flash Warning Labels Be Placed on Electrical Panels and Switchboards. • IEEE 1584 is Preferred Method for Determining Arc Flash Incident Energy & Arc Flash Boundaries. – Fault Study – Coordination Study – Determine Incident Arc Energy