What is an Electric Arc?
By Steve Hudgik
An electric arc happens when there is a flow of electrical current between two electrical conductors separated by a gap. The gap is filled with a material that is normally an insulting material such as air. The electric arc typically creates a ionized conductive plasma, extreme heat and bright light.
An electric arc may be intentionally created and used for useful purposes such as arc lights, welding and electric furnaces. An electric arc may also be created unintentionally and be harmful such as when there is an arc flash or arc blast.
What is an electric arc? - Intentional Electric Arcs
You may not be aware of it, but low energy electric arcs are used all around you. Fluorescent lighting, and mercury and sodium street lights use low energy electric arcs to create light. The bright light from a camera or cell phone flash comes from a low energy electric arc.
Small electric arcs are now even being used for surgery, replacing scalpels.
High energy electric arcs are used for electric discharge machining, for arc welding and for creating intense heat in industrial electric furnaces. Electric furnaces have the ability to rapidly start up and change to adapt to changing loads. This makes them ideal for steel mills that need to frequently change production to adapt to customer needs. The intense heat created by an electric arc also makes electric furnaces the preferred technology for making substances, such as calcium carbide, that require large amounts of energy to manufacture.
What is an electric arc? - Controlling Electric Arcs
The intensity, brightness and temperature of an electric arc is controlled using several factors, such as:
- Distance between the electrodes
- Amount of power applied to the electrodes
- The type of gas in the gap between the electrodes
- The pressure of the gas
- The duration of power applied to the electrodes
For an arc to form the gas between the electrodes must become an ionized plasma. The type of gas used, and its pressure, will changes the characteristics of the arc. That affects the brightness, color and the amount of heat produced by the arc.
What is an electric arc? - Undesired Electric Arcs
An undesired electric arc is one that occurs in a location where it was not intended for an electric arc to happen. This might be in an electrical switch yard; in a circuit breaker; or when an electrical cable is damaged. Unintended electric arcs can cause damage to equipment and may injure or be fatal to people who are working on the equipment or even are just nearby.
An arc flash is a very short but extremely intense electric arc that may have explosive characteristics. The resulting heat is so intense that conductors may be vaporized. The metal vapor and molten metal will be blasted into the surrounding area. In addition to injuries from the blast, anyone close by will breath in the hot metal vapor and their lungs will be burned.
An arc flash, also known as an arc blast, happens very quickly and unexpectedly. Anyone working on equipment that has the potential for an arc flash must be using appropriate precautions and be protected by appropriate PPE.
Real-world advice and insight into preventing arc flash accidents.
Labels And Signs Protect Workers
Electric arc hazards are invisible. That means labels and signs are needed to warn people away from electrically hazardous areas. Labels and signs inform workers about the need to be a qualified person before entering certain areas or working on electrical equipment. Labels and signs inform electrical workers about needed PPE.
The labels and signs you need come from DuraLabel printers.
DuraLabel makes the label printers that produce effective, long-lasting, easy-to-apply, industrial quality labels, signs and tags. With a single DuraLabel printer you can quickly make:
- arc flash labels
- panel labels and wire markers
- conduit markers
- equipment labels
- safety signs and labels
- outdoor warning and danger signs
DuraLabel printers and supplies are so good they come with warranties that are not matched by any other brand. Plus with DuraLabel's availability of more than 50 types of supplies, you can always get the right labeling supply for the job. Call 1-888-326-9244 for more information.