Understanding Arc Flash: What You Need To Know To Stay Safe
4-10-18 | Business | Jeff Rausch
What is an Arc Flash?
An arc flash occurs when a flashover of electric current leaves its intended path and travels through the air from one conductor to another, or to the ground. When a worker is in proximity of the arc flash the results can be serious injury or even catastrophic (death).
What Causes an Arc Flash?
Arc flash are most often caused by the following six factors:
- Dust/Debris Accumulation
- Dropping Tools
- Accidentally Contacting Live Parts
- Faulty Installation
Arc flash can also occur spontaneously if electric equipment fails.
Factors Impacting the Injury Severity
There are three factors that influence the severity of an injury sustained from an arc flash:
- Proximity of the worker to where the flash occurs. If the worker is using good switching techniques like standing to the side of the disconnect then the resultant injury will be minimized.
- Temperature – the higher the voltage the higher the arc flash temperature
- Time needed for the circuit to breaker to cut off the flow of electric energy.
The typical results of arc flash include the following:
- severe burns
- fires that have the potential to spread rapidly depending on specific circumstances
- flying objects and molten metal
- blast pressure in excess of 2000 lbs/ft2
- intense heat around approximately 35,000 degrees (F)
- a sound pressure of around 140 decibels
How to Prevent an Arc Flash
The most effective and fool-proof way to ensure that you don’t become an arc flash victim is to always de-energize the circuit before attempting work.
Other effective arc flash controls include:
- the use of good electric safe work techniques
- insulation on tools and in the work environment
- proper use of guarding and barricades
- Ground Fault Circuit Interrupters (GFCI)
- proper system grounding
If you must work on live electric circuits use of good work techniques is essential.
A safety-related written plan should be developed and enforced on prevention of electric shock from either direct or indirect electric exposure. These safety-related work plans should include at a minimum:
- the details of a permitting system for energized electric work
- personal protective equipment requirements
- insulated tools/mats
- job briefings prior to engaging in work
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