HGI Practice

Slide 1: 

Arc Flash and NFPA 70E Electrical

Electrical Hazards : 

Electrical Hazards Shock Account for 600-1000 deaths per year Arc Flash Up to 80% of reported electrical injuries Arc Blast Caused from pressurized air and expansion of vaporized metal resulting from the arc

Electrical Shock : 

Electrical Shock

Arc Flash : 

Arc Flash Definition: The passage of electric current between two conducting metals through ionized gas or vapor, usually air. Initiated from either a flashover or introduction of some conductive object (like a screwdriver). Play Video

Arc Flash Facts : 

Arc Flash Facts Can be up to 35,000? F About 4x hotter than surface of the Sun Molten metal thrown many feet in air Workers several feet from the source can receive severe or fatal burns

Arc Blast : 

Arc Blast Play Video

Arc Flash Images : 

Arc Flash Images

Arc Flash Images : 

Arc Flash Images

Arc Flash Images : 

Arc Flash Images

Arc Flash Images : 

Arc Flash Images

Arc Flash Images : 

Arc Flash Images

Arc Flash Images : 

Arc Flash Images

Skin Tolerance : 

Skin Tolerance

NFPA 70E : 

NFPA 70E Electrical Safety in the Workplace Goes beyond just Arc Flash Defines shock and arc boundaries Defines Hazard/Risk categories Defines required personal protective equipment (PPE)

Approach Boundaries : 

Approach Boundaries Limited: A protection boundary to be crossed by only qualified persons (at a distance from a live part) which is not to be crossed by unqualified persons unless escorted by a qualified person. Restricted: A protection boundary to be crossed by only qualified persons (at a distance from a live part) which, due to its proximity to a shock hazard, requires the use of shock protection techniques and equipment when crossed. Prohibited: A protection boundary to be crossed by only qualified persons (at a distance from a live part) which, when crossed by a body part or object, requires the same protection as if direct contact is made with a live part. Flash Protection: The FPB is a safe approach distance from energized equipment or parts.

Approach Boundaries : 

Approach Boundaries

Incident Energy : 

Incident Energy Definition: Energy per unit area received on a surface located a working distance away from flash location. Units: Cal/cm2 Example: 1 Cal/cm2 is equivalent to energy produced by a cigarette lighter in 1 second.

Hazard Categories : 

Hazard Categories Category 0: Up to 1.2 Cal/cm2 Category 1: 1.2 to 4 Cal/cm2 Category 2: 4.1 to 8 Cal/cm2 Category 3: 8.1 to 25 Cal/cm2 Category 4: 25.1 to 40 Cal/cm2 Over 40 Cal/cm2 : Unacceptable Risk

Reducing Arc Flash Accidents : 

Reducing Arc Flash Accidents Safe field practices Including Lock Out/Tag Out procedure Wearing proper PPE (Personal Protective Equipment) Arc-Resistant gear Proper warning labels

Lock-Out/Tag-Out : 

Lock-Out/Tag-Out

Personal Protective Equipment : 

Personal Protective Equipment Fire Rated (FR) Clothing Proper layering underneath Head, Eye, and Face Protection Take care of equipment Play Video

Arc Resistant Gear : 

Arc Resistant Gear Protection from internal fault Open space to disperse energy Reinforced doors/covers Shields around door-mounted equipment

Arc Flash Warning Labels : 

Arc Flash Warning Labels Flash Hazard Boundary Hazard Category PPE Requirements Voltage Limited, restricted, and prohibited approach boundaries