The violent, explosive expansion of air and vaporized metal that occurs during a severe electrical fault. The extreme heat of the arc vaporizes copper or aluminum instantly, expanding its volume by thousands of times and creating a concussive shockwave that can rupture switchgear enclosures and throw workers across a room.
Heard on the job
The arc blast blew the heavy steel doors right off the switchboard and shattered the windows.
Do not mix it up with
- Arc flash: Arc flash is the intense light and heat of the fault, while arc blast is the physical, concussive shockwave.
Related terms
Arc flash
Explosive release of heat, light and pressure when an electric arc forms through air between energised parts.
Arc fault
An unintended electrical discharge through the air between conductors.
Short circuit
Unintended low-impedance path between conductors at different potentials, bypassing the load.