Phoenix, AZ – Numerous buildings in the downtown area of Phoenix were without power for days following a recent fatal arc flash incident. One Arizona Public Service Electric Company (APS) worker was killed, and another was injured when an underground electric vault caught fire on Sunday June 30th.
Phoenix police report the name of the worker who died as Ricardo Castillo, age 42. Emergency crews who responded to the fire say that flames where shooting out of a manhole at the scene. Police have said that a 46-year-old worker had exited the vault, and suffered burns on his hands and face. That man was taken to a local burn center for treatment and later released.
Many in the Phoenix area were impacted by this tragic electrical flash fire. The fire that followed the arc flash left a number of downtown buildings and light-rail stations without power well into the week. According to a Maricopa County spokesperson, around 1,000 workers had to either take Monday July 1st off or work from home due to the power outage. Trials and hearings at the Maricopa County Superior Court complex had to be cancelled in the wake of this unfortunate event.
According to news reports, Castillo and the other APS employee were replacing a power cable in an underground vault when an electrical flash triggered a fire. APS and the Arizona division of OSHA will be working together to determine what caused the fatal arc flash.
An Arc Flash is an electrical explosion due to a fault condition or short circuit when either a phase to ground or phase to phase conductor is connected and current flows through the air. Arc flashes cause electrical equipment to explode, resulting in injury or death to workers and destruction of electrical equipment.
During an arc flash, temperatures may exceed 35,000° F. For perspective, the surface of the sun is 9000° F. The high temperature of an arc flash causes the surrounding air to heat very rapidly and exert extreme pressures, resulting in an arc blast. The arc flash or arc blast can vaporize all solid copper conductors. These copper conductors will expand up to 67x times their original volume when vaporized. The resulting arc flash produces fire, intense light, pressure waves, and flying shrapnel.
When an arc flash happens, it is without warning and lightning quick. The result of this violent event is usually destruction of the equipment involved, fire, and severe injury or death to anyone nearby. Proper safety and protection measures must be taken to limit the damage of an arc flash including conducting arc flash studies, hazard analysis and labeling, short circuit studies, and NFPA 70E electrical safety training. Please contact an electrical safety specialist at Martin Technical if your plant or facility has any concerns about arc flash risks.