When safety and reliability are not optional
Investing in arc resistant switchgear
Arc resistant switchgear has a huge role to play, especially in critical, complex, and large continuous operations such as data centers, power generation plants, petrochemicals, refineries and hospitals. The benefits of arc resistant switchgear are both tangible and intangible and impact employee safety, equipment reliability, and general productivity. The value of arc resistant switchgear for risk mitigation and avoidance of the potential costs when those risks are minimized is immeasurable.
To fully understand the benefits associated with arc resistant switchgear, it is first necessary to understand what an arc flash is, and the damage and destruction that result when an arc flash occurs.
What is an arc flash?
The U.S. National Fire Protection Association (NFPA) defines an arc flash as “a dangerous condition associated with the release of energy caused by an electric arc.” Arc flash temperatures can be up to five times the surface temperature of the sun (20,000°C) with light intensity more than 2000 times that of normal office light. In addition to the intense heat generated, arc flashes have a rapid onset of only 10-15 milliseconds allowing no time for action before resulting in powerful explosions. These fireballs spew shrapnel, pressure waves, hot gases, toxic fumes, and molten metal, endangering human life and causing catastrophic equipment damage.
Arc faults can be triggered by several factors e.g. improper maintenance, mechanical, and interlock failures; failure to follow procedures; gradual component or insulation breakdown; and foreign objects, such as rodents or snakes.
Data centers and arc flashes
Modern data centers use approximately 30 times the power needed to run the average office building. That’s about 80 million megawatt hours of electricity a year, which provides ample opportunities for danger. The consequences of an electrical mishap in a data center can be dire. In addition to the potential for injuries and loss of life, arc flashes can also destroy equipment, causing extensive downtime and requiring expensive replacement and repair. They can also ignite nearby flammable materials, resulting in secondary fires that can destroy entire facilities. Studies estimate the minimum cost of a data center electrical incident at around $750,000.
Data center absorption costs from a catastrophic arc flash and consequential loss of power include:
- Damage to equipment and materials
- Customer charges for downtime in web hosting services
- Lost business – lead times of 14–16 weeks for switchgear equipment replacement
- Installation and commissioning costs of the new equipment (if not supported in warranty)
- Lost employee time
- Lost profits
- System damage inspection costs for other plant equipment and the needed repairs
- Negative impact on company reputation and credibility
- And most importantly, potential loss of life
Data center owners face a delicate balancing act. They must walk a fine line between ensuring the safety of personnel, facilities, and equipment while maintaining 24/7/365 availability of mission critical systems.
As multi-megawatt facilities, data centers are particularly susceptible to arc-flash events, which strike anywhere from five to 10 times a day across the U.S. alone, with about 20% occurring in motor control centers and switchgear, and another 18% taking place in custom control panels.
Arc resistant switchgear making a difference
Many data centers have redundant or backup operating systems to limit downtime and switchgear is often the heart of these redundant systems, orchestrating the electrical flow between the two. As a result, an arc flashing event involving switchgear cannot be readily alleviated.
Increasingly, data centers are embracing arc resistant switchgear to contain the energy produced by an arc flash, minimizing damage to both people and equipment. Arc resistant switchgear is designed to route expanding hot gases resulting from an arc flash through a system of vents and flaps away from workers at the front, rear, and sides of the switchgear.
The switchgear doors, walls, and panels are reinforced and sealed to withstand the temporary pressure surge until relief vents and flaps operate. This design helps ensure that damage is contained in the compartment of fault origination, rather than spreading to adjacent compartments.
So? Is it worth it?
The immense amount of power available at data center switchgear and motor control centers creates an ideal environment for arc flash occurrences. Arc resistant switchgear can significantly reduce the risk of catastrophic damage to people, equipment, and facilities, reduce downtime, and improve reliability and productivity.
 “Ten Ways to Ensure the Safety of Data Center Employees,” ABB Data Centers white paper, November 8, 2013.