What is electrical arc and Hazards related to electric arc ?

What is electrical arc?

An electric arc is a visible plasma discharge caused by electrical current ionizing gases in the air. Electric arc is explosive, it will last less than 1 second but will emit high radiant energy which can light and even melt daily clothes .The core temperature of electric arc can reach 20,000℃. Electric arc may induce many secondary hazards such as hot gases, molten metal splash, pressure waves, and even high decibel noise and electric shock.

What is electrical arc?

Even though there is a fraction of a second, the harm may last lifelong. Every day, hundreds of thousands of Electric workers are exposed to electric arc hazards, including electrician, wire maintenance inspectors, power plant workers, substation and transformer operators, maintenance technician, etc.

Hazards related to electric arc

01 Electrocution

When contacting electric arc directly, it will cause electrocution or severe burns. And even flame resistant garments cannot protect from the hazard of electrocution.

02 Severe burns caused by electric arc

A worker may get injured even without contacting electric arc. Electric arc will generate extreme radiant heat which may melt tools and light daily clothes. And once the clothes are lighted, they will continue to burn and increase the injury.

03 Severe burns caused by burst of clothing

The explosion or impulse caused by electric arc can blast apart daily clothes and expose the body to heat, flame and melted equipment.

04 Severe burns caused by melted underwear made from synthetic fiber

Heat caused by electric arc will melt underwear made from synthetic fiber even the outerwear is not burning.

05 Severe burns caused by the secondary flame

The intense heat of electric arc can cause fire disaster and additional explosions. For example, electric arc can light transformers or explode nearby constructions.

Generally, the incident energy is affected by different fault current, time duration and working environments (opened air or sealed air). It is important to learn that the time duration of electric arc is critical to burn degree. Since the energy caused by electric arc is affected by time duration and current, the burn degree caused by lower fault current and longer time duration will be severer than it caused by higher fault current and short time duration. And even a relatively lower voltage system (480/227V) will form an electric arc of 3 to 4 inches and will last a long time.

There are many variables for electric arc explosion. Therefore, although statistical method could be used to analyze hazards caused by arc current, the real hazard may be different. Due to the unpredictability of arc explosion, electrical workers will definitely need protective clothing in the workplace where electric arc energy can affect.