What is an Arc Flash?
An arc flash is the result of a rapid release of energy due to a short circuit through the air. Superheated air turns into highly conductive plasma, helping to sustain the arc, and leading to:
- Heat, up to 20,000°C (35,000°F)
- Sound, can exceed 160dB
- Shrapnel, can exceed 1,100km/h (700mph)
- Concussive shockwave, can exceed 50,000N/m2
An arc flash can burn and vaporize bus bars and devastate everything in its path.
In general, arc flash current is lower than the available bolted fault current. If circuit breakers are not set to handle the arc flash current, these devices will not trip during an arc flash fault thus allowing the arc flash forces to occur.
Responding to the Risk
In the past, industry saw the risk of arc flash as an unavoidable part of working with electrical systems. Today, with higher safety standards and more effective mitigation strategies, we study, assess and take measures to increase awareness and reduce or ideally eliminate the risk or hazard.
Standards for Electrical Safety in the Workplace
- NFPA 70E - USA
- CSA Z462 - CAN
These standards cover the entire range of electrical safety issues from work practices and maintenance to special equipment requirements and installation.