What is Arc Resistant Switchgear and How it Works?

Arc resistant switchgear designs are intended to provide protection for workers and equipment against the hazards of an electrical arc. Improved versions of switchgear come fitted with features designed to attempt to minimize or eliminate the results of electrical arcing. To put this even more clearly, prepared below is a step-by-step guide that will help you get insight into how this type of switchgear works, showing major characteristics and ways of protecting both personnel and machinery.

Arc-resistant switchgear will provide safety through reduction of possible electrical arcs. This is highly specialized equipment fitted with a number of new innovative features to deal with and reduce the risks associated with arcing. The guide will then go through functions of the arc-resistant switchgear, with emphasis on protecting competencies and explain how that secures workers and equipment.

What Is An Arc Resistant Switchgear?

Arc resistant switchgear helps pacify the threats and legal liabilities for those workers and operators associated with high-risk power distribution equipment by diverting away electrical explosions, known as arc flash events, from those present.

Arc resistant switchgear has specially reinforced compartments that can handle extremely large pressure increases during high-energy faults. It is many times safer, more reliable, and at a fraction of the realized cost compared to the dangers presented by arc flashes.

Arc resistant switchgear allows for the servicing of equipment by facility workers to take place without risk for accidents and injuries due to arc flash. Here is what is so dangerous during a switchgear arc flash:

• First of all, the temperature of an arc flash can become as high as 35,000 degrees Fahrenheit—sufficient to either melt certain metals or cause them to undergo vaporization.
• The second is that explosive shockwaves can be generated by pressure from an arc flash. These shockwaves can blow out panels and project out parts with forces that can easily kill a person that is nearby.

Arc-resistant switchgear can prevent these dangers along with high-voltage switchgear explosions themselves. Those switchgears are made with special provisions and have the capability to contain and divert the arc away from an individual or people working on or near the switchgear.

The result is that arc-resistant switchgear brings an abundance of protection, allowing humans to maintain power distribution systems in a much safer manner while reducing a serious injury or huge damage to equipment.

Why Use An Arc Resistant Switchgear?

Arc resistant switchgear has been designed to lessen an arc flash’s energy and reduce or reroute it from employees and equipment. But exactly what is an arc flash, why is it so hazardous and what causes it?

An arc flash occurs whenever an electric current flows through ionized air, normally as it tries to jump from one conductor to another. This energy release becomes almost instantaneously transferred into light and extreme heat, which causes the surrounding air to almost instantly expand, creating an explosion. Other common causes of arc flashes include:
Human error, especially while working on live equipment as part of maintenance
The massive amount of voltage and amperage flowing through the controls of switchgear directly identifies it as a piece of gear that is highly prone to massively destructive arc flash events. The potential of a serious injury or a fatality represents a high risk for utilities, campuses, and facilities worldwide.

Available at a marginal premium of about 7% over common switchgear, arc resistant switchgear provides an added safety level for the technician, engineer, or other facility employees who work on live power distribution equipment. The arc-resistant gear is designed limit and contain the damage due to internal arc faults, providing the best level of safety to personnel, long-term cost savings, and insignificantly reduced downtime.

Overall, the arc-resistant switchgear is necessary in the reduction of damages by the injurious forces of arc flashes, in the assurance of tolerable safety for the workers, and in keeping up with the increased efficiency and reliability of power supply systems.

Reasons to use Arc Resistant Switchgear

While the first cost of arc-resistant gear is 10-15 percent higher than standard gear, more users are installing this newer design in data centres, where its use is not required by the consensus standards that direct the design of viable commercial electrical systems. For the obvious reason of safety, above all else, five other factors are making arc-resistant gear the preference among more users for this application, as well as in other installations.

Arc-resistant low- and medium-voltage switchgear is designed to significantly reduce the risk of dangerous electrical arcs. This is done thanks to a removable module disconnection and de-energizing possibility before the equipment is opened, rather than being opened with live parts behind the door. If an arc occurs, the energy is safely vented away from people and equipment, with damages confined to the arc-resistant, blast-hardened cabinet. Maintenance is allowed without restrictive Category 3 or 4 Personal Protective Equipment. In turn, this process will be faster and have a reduced chance of error.

Simpler Systems

The same switch gear in conventional applications would therefore need to have an active fault-protection system in which every asset is monitored constantly and tripped at the very first sign of increased current. These systems are, in a sense, more complex, expensive, and require periodical testing and maintenance. With the inherent design focus on protection itself, arc-resistant gear provides passive protection, virtually eliminating the need for any other flash detection. This results in fewer pieces to purchase or maintain, essentially balancing out the initial cost difference.

Faster Recovery from Incidents

Arc flashes happen far more often than generally realized—tens of thousands of on-the-job injuries in any given year. An arc flash in nonresistant switchgear can lead to the unavailability of equipment near the happening due to costly service outages. For arc-resistant switchgear, the damage will be isolated to the unit containing the fault, so recovery will be faster. Downtime is reduced, and more often than not, the supported service level agreements for redundancy can be met easily. Also, in the event of an occurrence sans arc-resistant equipment then injury is bound to occur, among other aspects, regulatory bodies, and litigations, hence resulting in more downtime on fixing things.

Insurance Favorability

Most underwriters are usually reported to be offering incentives to change into arc-resistant equipment due to its advantage of dropping the risk, downtime, and protection of the company in litigation in the case of injuries and death. Safe equipment results in a drop in costly occurrences and hence a low insurance premium as a whole.

Endorsements All Over

While lifecycle costs and insurance savings may not always be discussed as part of the design process for electrical systems, more and more consulting engineering firms are recommending, and in some cases actually requiring, customers to use arc-resistant gear on new installations. In fact, some firms will not do a job unless a waiver is signed by the customer if the work does not include this enhancement. Arc-resistant designs are safer and provide better system performance, thus making them cost-effective over their lifecycle.

While this surely comes with a premium up front, arc-resistant switchgear presents real safety and real operational benefits. Making sure it becomes one of the fastest-growing recommended additions to a data center or a facility of like kind.

Frequesntly asked questions about Arc Resistant Switchgear

What Are the Arc Resistant Switchgear Types

The design of the arc-resistant switchgear shall be for various arc mitigation capabilities, as defined in the ANSI standard C37.20.7. In the said standard, there are two major types of arc-resistant switchgear: Type 1 and Type 2—both providing different levels of accessibility and protection to the user.

Arc-Resistant Switchgear Type 1

Type 1 arc-resistant switchgear provides protection only at the front. Operators are safe while positioned in front, but not from the sides or back. This entry-level application has limited protective coverage; hence it is less applied and passes fewer arc resistance needs.

Arc-Resistant Switchgear Type 2

Type 2 switchgear offers protection from arc flash on all sides: front, back, and sides. Type 2 is further divided into Type 2B and Type 2C, both with more added protection.

Arc-Resistant Switchgear Type 2B

Type 2B switchgear is similar to Type 2, but with an added feature of having extra protection when the low voltage compartment is open. This feature makes it more protective to the operators or, at best, a much safer option.

Arc-Resistant Switchgear Type 2C

The rating for Type 2C switchgear is the highest for any switching gear equipment in arc resistance. It combines features found in Type 1 and Type 2B, with the addition of extra protection in individual compartments. This rigorous design ensures maximum safety when operators work with the equipment.

Among them, Type 2B has the largest usage due to its additional safety features, while Type 1 represents the smallest due to its limited range of protection.

What Is An Arc Flash?

Arc flash events occur very frequently and are extremely dangerous. An arc flash is electrical energy that has been released from its circuit and travels through the air in an explosion of an amazing degree of violence. It can create temperatures up to 35,000 F with arcing heat, high voltage, and a huge shockwave. Not even specialized PPE offers those close to an arc flash much chance of escaping serious injury or probable death.

As reported by Industrial Safety & Hygiene News, there are about 30,000 arc flash incidents annually, resulting in over 7,000 burn injuries, 2,000 hospitalizations, and 400 deaths. Dropped tools or parts; material wearout, failure, or wrong selection; corrosion; condensation; leaks; dust accumulation; or other factors may lead to an arc flash. Though many such incidents can be averted with awareness and preparedness, unexpected incidents do take place quite often.

Final Thoughts

An arc flash in switchgear creates an explosion that has the potential to cause critical damage to equipment and injure or kill workers, possibly triggering fires. Thus, it is one of the major switchgear room hazards. Because of dangers associated with an arc flash event, most electricians would prefer an arc-resistant switchgear. This special, engineered switchgear contains and redirects the energy created by an arc flash, protecting people and equipment from its harmful effects. For more information please contact us.