What is an arc flash explosion?
It 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.
What causes an arc flash explosion?
It can result from accidental contact with the electrical systems, the buildup of conductive dusts, corrosion, dropped tools, or improper work procedures. The plasma arc has a virtually unlimited current carrying capacity once it’s established. The energy of an arc flash converts primarily to heat and light.
What is arc flash in switchgear?
An arc flash is the light and heat produced as part of an arc fault, a type of electrical explosion or discharge that results from a connection through air to ground or another voltage phase in an electrical system.
What is the most common cause of an arc flash?
Human error is the most common cause of arc flash. After a worker has performed the same task over and over without incident, they may bypass a maintenance step or develop a procedural workaround to save time.
Is arc flash required for 208v?
At these locations, there is definitely an Arc Flash (and blast) hazard. However, a low power source such as a 45 kVA 480 – 208 V distribution transformer most likely will not have enough energy to have a arc flash be self sustaining.
What are the dangers of arc flash?
Dangers of arc flashes An arc flash can cause minor injuries, third degree burns and potential death as well as other injuries including blindness, hearing loss, nerve damage and cardiac arrest. Fatal burns can occur when the victim is several feet from the arc. Serious burns are common at a distance of 10 feet.
How can arc flashes be prevented?
How to prevent Arc flash
- De-energize electrical equipment.
- Wear suitable Personal Protective Equipment (PPE)
- Keep at a safe distance.
- Reduce the energy output from an incident.
- Carry out a risk assessment.
- Train on-site workers to control risks and interrupt faults.
Where do Arc flashes happen?
Simply put, an arc flash is a phenomenon where a flashover of electric current leaves its intended path and travels through the air from one conductor to another, or to ground. The results are often violent and when a human is in close proximity to the arc flash, serious injury and even death can occur.
What is the danger of arc flash?
How many arc flash incidents a year?
30,000 arc flash incidents
A report published in Industrial Safety and Hygiene News estimated that, on average, there are 30,000 arc flash incidents every year. The report went on to estimate that those incidents resulted in an average annual totals of 7,000 burn injuries, 2,000 hospitalizations, and 400 fatalities per year.
What are the side effects of arc faults?
Impacts of power system arc faults The arc flash easily causes a fire, which, in addition to the immediate damage, also creates fire gases and consequential damage due to smoke and stain. The fire gases of burning electrical devices are particularly dangerous for people residing in the same area.
Can 120v arc flash?
120 volts does not provide sufficient energy to cause an arc flash hazard. Most 480V electrical services have sufficient capacity to cause an arc flash hazard. Medium-voltage equipment (above 600V) is higher energy and therefore a higher potential for an arc flash hazard.
What is arc resistance switchgear?
Arc Resistance Switchgear During the course of an arc flash within enclosed equipment, severe pressure can build up over time which can result in a massive explosion which can prove to be fatal to personnel nearby.
What causes an arc flashover?
There are several reasons for an arc flashover taking place in a medium voltage switchgear. What causes arc flash can be summarized as follows: Electrical equipment can be damaged as well with flashovers over 50kV resulting in permanent damages to the insulation, electrical fires etc.
Why are arc flash hazards of greater concern in medium-voltage switchgear?
There are many reasons why mitigation of arc flash hazards is of greater concern in medium-voltage equipment. First, medium-voltage switchgear occupies a higher hierarchical position in most radial distribution systems.
How does switchgear protect against arc flash?
Switchgear designed and tested to mechanically withstand the electric arc. Protection is afforded by the containment of the arc within the switchgear and the means to direct the arc gases and debris to a safe area. Passive solutions also include advanced switchgear design features to reduce the probability of an arc flash occurring.