Calculating Flash Protection Boundary Distances
In NFPA 70E, the short-circuit symmetrical ampacity from a bolted 3-phase fault at the transformer terminals is calculated with the following formula: where Isc = Amperes, V = Volts, %Z …
Arc-Flash Hazards
An arc-flash is a release of energy caused by a flow of fault current through an electrical arc plasma. Arc flashes can occur when racking a breaker in/out, removing a …
Arc Flash Incident – 13.8 kV Indoor Switchgear Part II
Accumulation of moisture inside the 13.8 kV main bus and insulation tracking caused another arc-flash incident on the 13.8 kV Indoor Switchgear. An annual preventive maintenance was scheduled prior to …
Arc Flash – Hazard and System Grounding
IEEE 1584 Guide Equation for calculation of incident energy has a factor K2 for system grounding. It is zero for ungrounded and high or low resistance grounded systems and −0.113 …
Arc Flash – Simplified Two-Category Clothing
The 2015 edition of NFPA 70E has a simplified approach to provide minimum PPE for electrical workers within facilities with large and diverse electrical systems. The simplified clothing categogies listed …