Arc Protection Frequently Asked Questions
What is Arc Flash?
Arc flash is an electrical explosion caused by a low impedance ground or another phase in an electrical system. High temperatures cause rapid heating and extreme pressure of the surrounding air, leading to arc explosions. An arc blast (the result of an arc flash) could vaporize all solid copper conductors, which would expand to 67,000 times their original volume when vaporized.
Arc blasts release flames, intense light, and pressure waves in an explosion of flying shrapnel. Arc flashes occur without warning. This often results in the complete destruction of the equipment involved and, in the event of an accident, serious injury or death of persons within the arc flash boundary.
The energy delivered by an arc flash is a function of the system voltage, the fault current available at that location, and the duration of the arc.
Should you be concerned about arc flash hazards on low voltage equipment?
The theory that the arc flash hazard is greater at higher voltages is a common misconception. For low voltages (like 480v) it is more common to have a higher level of arc flash hazard due to the higher fault current.
Most recorded arc flash incidents occurred at lower voltages because the failures were caused by technicians working on electrical equipment.
It is not uncommon to have a Category 3 or 4 arc flash hazard on low voltage systems due to the long clearing times and high fault currents of protective devices.
What causes arc flash?
When a large fault current flows through multiple conductors in close proximity to each other, the potential difference, among other factors, will ionize the air, creating low resistance paths between the conductors.
Incorrect tools, incorrect electrical equipment, corrosion of electrical equipment, improper work techniques, lack of electrical safety training, and lack of preventative maintenance are just some of the events that make arc flashes more likely to occur.
What kind of damage can an arc flash cause?
An estimated 5 to 10 arc flashes and explosions occur daily on electrical equipment in the United States, and 2,000 people enter burn centers each year with severe burns.
The degree of injury is directly related to the power of the arc flash, the distance of the person at the time of the arc flash, and the protective equipment (PPE) the individual is wearing during the arc flash.
Burns, concussions, lung failure, hearing loss, shrapnel injuries, and bone fractures are common injuries due to the force of the energy blast and heat.
What are the costs associated with an arc flash incident?
The total cost of an arc flash incident is estimated to be between $12 million and $15 million, including medical bills, downtime, equipment replacement, litigation, and insurance and litigation costs.
OSHA has imposed fines of more than $500,000 on some facilities for failing to comply with electrical safety regulations. The greatest cost is possible litigation because employers do not properly identify hazards, train employees, and provide proper warnings, procedures, and protective equipment (PPE).
Arc flash is an electrical explosion caused by a low impedance ground or another phase in an electrical system. High temperatures cause rapid heating and extreme pressure of the surrounding air, leading to arc explosions. An arc blast (the result of an arc flash) could vaporize all solid copper conductors, which would expand to 67,000 times their original volume when vaporized.
Arc blasts release flames, intense light, and pressure waves in an explosion of flying shrapnel. Arc flashes occur without warning. This often results in the complete destruction of the equipment involved and, in the event of an accident, serious injury or death of persons within the arc flash boundary.
The energy delivered by an arc flash is a function of the system voltage, the fault current available at that location, and the duration of the arc.
Should you be concerned about arc flash hazards on low voltage equipment?
The theory that the arc flash hazard is greater at higher voltages is a common misconception. For low voltages (like 480v) it is more common to have a higher level of arc flash hazard due to the higher fault current.
Most recorded arc flash incidents occurred at lower voltages because the failures were caused by technicians working on electrical equipment.
It is not uncommon to have a Category 3 or 4 arc flash hazard on low voltage systems due to the long clearing times and high fault currents of protective devices.
What causes arc flash?
When a large fault current flows through multiple conductors in close proximity to each other, the potential difference, among other factors, will ionize the air, creating low resistance paths between the conductors.
Incorrect tools, incorrect electrical equipment, corrosion of electrical equipment, improper work techniques, lack of electrical safety training, and lack of preventative maintenance are just some of the events that make arc flashes more likely to occur.
What kind of damage can an arc flash cause?
An estimated 5 to 10 arc flashes and explosions occur daily on electrical equipment in the United States, and 2,000 people enter burn centers each year with severe burns.
The degree of injury is directly related to the power of the arc flash, the distance of the person at the time of the arc flash, and the protective equipment (PPE) the individual is wearing during the arc flash.
Burns, concussions, lung failure, hearing loss, shrapnel injuries, and bone fractures are common injuries due to the force of the energy blast and heat.
What are the costs associated with an arc flash incident?
The total cost of an arc flash incident is estimated to be between $12 million and $15 million, including medical bills, downtime, equipment replacement, litigation, and insurance and litigation costs.
OSHA has imposed fines of more than $500,000 on some facilities for failing to comply with electrical safety regulations. The greatest cost is possible litigation because employers do not properly identify hazards, train employees, and provide proper warnings, procedures, and protective equipment (PPE).
