What is Electrical Arc Flash?
When having the electrical installation, maintenance, troubleshooting, short circuits, or repair, because of insulation failure or accidents, electric current flows through air gaps between conductors and causes a short circuit, electrical arc flash will happen.
What is Test Method of Electrical Arc Flash?
NFPA 70E is the world’s well-known standard on Arc Flash protection, the standard is designed to advise and determine protection categories for Personal Protective Equipment (PPE) when working environment areas where an arc flash is possible
Arc Rating is the value described to materials that describe their performance when exposed to an electrical arc discharge, the Arc Rating is derived from the determined value of the Arc Thermal Performance Value (ATPV) and based on Hazard Risk Category (HRC)
HRC is the safety standard that shows the minimum amount of PPE (Personal Protective Equipment) protection a worker needs based on the potential exposure to a hazard, ranging from 0 to 4, with 4 being the highest risk. ATPV is the incident energy needed to cause a second-degree burn; this value is provided in calories per centimeter squared (Cal/cm²).
The PPE (Personal Protective Equipment) should always be selected to match or exceed the PPE Category rating of the equipment worked on, the following are the four hazard risk categories, examples of each, and what type of arc flash rating it provides.
CAT 1:Minimum Arc Rating 4 Cal/cm2
CAT 2: Minimum Arc Rating 8 Cal/cm2
CAT 3: Minimum Arc Rating 25 Cal/cm2
CAT 4: Minimum Arc Rating 40 Cal/cm2
The PPE (Personal Protective Equipment) includes Arc-rated long-sleeve shirts and pants or coverall, Arc-rated face shield or arc flash suit balaclava/hood, Arc-rated jacket, high-visibility apparel, rainwear, or helmet lining. The Arc flash risk assessment should precede every decision, as it will help you learn which category of PPE you require for your work environment.