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Learn about arc flash events, OSHA guidelines, NFPA 70E requirements, impact on industry, PPE selection, and more. Ensure safety with proper protective clothing.
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Arc Flash Energy & Protection Presented by EWB Engineering (Electrical Engineers)
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
Arc Flash Event Every Day An Electrician Is Severely Injured by an Arc Flash Event
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
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
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.
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.”
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.
Results of Arc Flash Analysis • Flash Protection Boundary • Incident Arc Energy • Hazard Level for PPE
Arc Flash Principles • Radiated Energy From Flash • Radiated Energy Function of • Arc Power • Distance From Arc • Time to Extinguish Arc • Arc Power Function of • Arc Voltage & Arc Current • Arc Voltage Function of • Arc Gap
Incident Arc Energy The amount of energy impressed on a surface, a certain distance from the source, generated during an arc event.
Arc Flash Boundary A distance from exposed live parts within which a person could receive a second degree burn.
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
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
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
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 Arc Flash PPE Categories
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
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
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
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