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On average, 5 to 10 arc flash events occur in electrical equipment per day in the U.S. These events can be devastating to personnel and productivity. In this post, we’ll look briefly at why these events continue to happen, and three reasons that it’s important for your organization to consider using the newest available technology to upgrade arc flash protection.
Major switchgear suppliers have proven designs that reduce the risk of arc flash, but arc flash events are still far too common. Why? Here are just a few possible causes:
- Equipment may have been improperly installed, or there may be poorly made connections.
- Connections or contacts can become corroded, and contacts can be damaged during rack in/out procedures.
- There may be insufficient maintenance being done on circuit breakers.
- There may be instances of human error, such as tools left behind in cabinets.
For maximum protection against arc flash, operations and maintenance personnel should never be working on or near live equipment. But the reality is that working around energized equipment is often required, especially in environments where maximizing uptime is critical. So, it’s a top priority to have proper training and rigorously-followed procedures, including the use of personal protective equipment (PPE).
But, even with these procedures, there is always the risk that an arc flash event may occur. You may ask: doesn’t switchgear have built-in arc protection? Electrical standards require that overcurrent protective devices be included in all switchgear for safety. But adequately suppressing an arc flash requires faster performance. For the maximum protection, additional arc flash protection solutions should be considered.
Has your organization considered upgrading its arc flash protection? Are you concerned about the cost? Dr. Mary Capelli-Schellpfeffer, principal investigator for Chicago-based research and consulting firm CapSchell, Inc., states that in the highly competitive global marketplace “economics is constraining safety … Arc flash is a low probability/high cost event. Therefore, it is difficult to argue for prevention dollars.”
But what is the real cost of an arc flash to your organization? And have you considered where electrical and safety standards are heading? The following are three good reasons to seriously consider upgrading arc flash protection in your facilities.
1. Reducing risk to personnel
Arc flash is extremely dangerous to workers. The heat, brightness, gases, and explosion force from an arc flash can cause severe burns, eye damage, lung damage, hearing loss, broken bones, and electrocution. Every day in the U.S. at least one victim of arc flash is sent to a special burn center, with many more being sent to hospitals and clinics. Worse, CapSchell reports that there are one or two deaths a day from these multi-trauma events.
Beyond the human cost, the costs to companies for these incidents is high. In 2016, the organization Mission Critical reported that the average cost of an electrical accident to a company was around $750,000, including medical bills and worker compensation payments.
And the cost of electrical injuries can be disproportionately high compared to other types of workplace accidents. For example, within the electric utility industry, the Electric Power Research Institute (EPRI) reported that over a 10-year period there was a total of 872 thermal burn and electric shock injuries representing 3.7% of all injuries, but accounting for nearly 13% of all medical claim costs, and this number does not account for the potential costs of fines and insurance claims.
Given the substantial risk and impact of arc flash on personnel, and the associated financial penalty to a company, cost effective solutions that directly address this challenge are a wise investment.
2. Avoiding loss of productivity
An arc flash can cause expensive equipment damage by burning insulation and starting a fire inside the electrical cabinet. If extreme enough, it can escalate, starting additional fires. Switchgear and other machinery can be damaged, sometimes beyond repair, requiring complete replacement. An arc flash is an explosion, with the blast pressure potential to destroy nearby walls, doors, roofs, or entire buildings.
All this damage will result in power outages to part or all of a facility. For critical processes, the resulting downtime can be expensive. In 2016, Aberdeen Group estimated the average cost of downtime across all business types to be $260,000 per hour. For some industries, the costs are much higher. Nielsen Research reported in 2006 that downtime losses for an automotive plant could run as high as $50,000 a minute! Today, these estimates would certainly be much higher.
Note that older facilities may be more susceptible to arcing incidents. This is due to older switchgear that is not only experiencing aging parts and insulation, but also not designed to meet today’s arc flash standards. Upgrading the arc protection of such equipment can help prolong its service life.
3. Advancing arc protection standards
Up to now, there have not been international standards for arc protection deployment. However, arc protection has become a ‘de facto’ standard in some countries, and there are a few established standards in different regions. For example:
- IEC 62271-200 – This standard specifies measures to decrease the probability of arc faults, and offers examples of arc protection technologies.
- IEEE 1584-2018 – This guide provides calculation methods for arc flash energy and lists useful definitions.
- NFPA 70E – This standard, used in mainly in the U.S. and Canada, addresses safe electrical work and maintenance practices, with some links to arc protection.
Ultimately, though some standards recommend specific arc mitigation methods and technologies, they are not global or comprehensive.
Fortunately, new standards are in development. Currently in working group mode (as of February 2020), the IEC standards SC 121A and SC 121B are, respectively, defining “internal arc-fault detection and combined mitigation devices” and “integration of internal arc-fault mitigation systems” for low voltage switchgear and controlgear assemblies. Schneider Electric has been influential in the development of these first international standards for arc flash mitigation, which are part of the larger IEC 60947 standard.
These standards will give consultants, contractors, and end users higher confidence in choosing appropriate, compliant arc protection solutions, and in integrating and installing such devices and systems properly into electrical equipment.
Several arc protection technologies have been available for some time, from zone-selective interlocking, to current-limiting fuses and reactors, to busbar differential protection. However, the newest, leading methods are based on simultaneous, rapid detection of light and overcurrent.
Schneider Electric offers a full range of arc flash protection solutions. Our industry-leading arc flash mitigation solutions offer light and overcurrent detection, from standalone devices to system-level solutions that provide selective, multi-zone, and redundant protection. Designed to be installed in MV or LV cubicles, these solutions offer high speed detection capability. They are part of the Schneider Electric EcoStruxure™ Power platform and digital architecture, helping address key business challenges while making facilities safer, more reliable, and more efficient.
To learn more about this topic, download the “Arc flash eGuide: Helping protect people and systems from arc flash in medium voltage equipment.”