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 Arc Resistant Switchgear Undergoing Test For an Arcing Fault An Arc Flash is a Sudden Release of Heat and Energy Caused By An Electric Arc

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 –Live electrical parts that an employee may be exposed shall be de-energized unless additional or greater hazards are introduced. 29 CFR –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, “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 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 / cm 2 FR Clothing 01.2Untreated Cotton 15FR Shirt & FR Pants 28Cotton Underwear + FR Shirt & FR Pants 325Cotton Underwear + FR Shirt & FR Pants + FR Coverall 440Cotton 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

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

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