Electrical Safety

How to reduce downtime and protect revenue streams from arc flash events

Power outages are crippling for any kind of business; computers shut down, machines idle, and workers are unable to do their jobs. Even if the interruption only lasts a few seconds, it still takes time to restart systems after power is restored. Now imagine an arc flash occurred in your switchboard or motor control center (MCC), due to damage from a hurricane or other inclement weather incident. Depending on the severity of the electrical event, your operations may be down for hours, days, weeks, or even longer. And every minute of downtime means lost revenue and added expense.

Arc flashes are dangerous on several levels. The explosive power and intense heat vaporize anything nearby and the blast can cause severe harm to people, equipment, and facilities. The National Fire Protection Association® (NFPA®) estimates that 5 to 10 arc flash incidents occur every day and nearly 2,000 people are exposed to the harmful effects each year.

Aside from the serious risk arc flashes pose to people’s safety, the costs of an arc flash can stretch into the millions of dollars. Severe electrical incidents like these can decimate uptime, productivity, and business reputation for extended periods of time.

In this article, we’ll walk through …

Downtime and other costs related to arc flash events

While actual costs vary significantly, the Occupational Safety and Health Administration, (OSHA) has a calculator that projects direct costs of $47,192 and indirect costs of $51,911 for a burn injury, including downtime. At a 3% profit margin, more than $1.7M in incremental sales would be needed just to cover indirect costs that insurance does not reimburse. And if productivity is squelched, it is difficult to generate revenue.

Fortunately, there are now innovative prevention and mitigation technologies available to help protect you from potentially devastating arc flash costs.

Traditional arc flash protection methods are limited

When it comes to eliminating downtime and other costs due to arc flashes, traditional methods are a bit limited in their scope of protection. Most engineered arc flash mitigation controls rely on an upstream breaker tripping to extinguish a fault.

Even the fastest breakers take about 50 milliseconds to trip. That’s fast, but it still takes about three cycles to clear the fault. And regardless of injury or equipment damage, when the breaker trips it causes an unplanned outage that interrupts operations. Even in facilities like hospitals and data centers where sophisticated backup systems are in place, the 10 – 15 second transition to backup power presents a critical delay. This must be bridged by instantaneous power solutions. But many of these solutions can be expensive to install and maintain.

Use ArcBlok 2500 to eliminate one source of unplanned downtime

Schneider Electric™ has a documented history of arc flash prevention through innovation, including the creation of the ArcBlok 1200™ passive protection system that is designed, tested and patented to help contain and extinguish a line side arc flash event at the equipment’s maximum rated level. Along with the ArcBlok arc isolation unit, we designed a main MCC section with a reinforced structure and wireless thermal communicating system. This allows temperature to be read on a mobile device while outside the arc flash boundary.

ArcBlok 2500™, our latest innovation in arc flash prevention, applies a different approach to eliminate unplanned outage downtime – removing the breaker from the equation. ArcBlok is a passive line-side arc prevention solution that requires no power and is always enabled. Inside the cable vault designed with arc-resistant principals are the protective barriers that include the cabling and connectors on the line side, isolating and insulating each phase.

The barriers force arcing faults to elongate to create impedance (i.e., protection through barriers) that is impossible to overcome, causing the arc to extinguish itself in under 16.66 milliseconds. This clearing inside the isolated module results in an incident energy exposure of less than 1.2 cal/cm2. The module contains the energy exposure and exhaust cools below restrike temperature. With a less-than-one-cycle clearing time, there is no trip, no interruption of power, no damage to equipment, and no data loss. Instead, ArcBlok can send a notification that an event occurred, so a staged shutdown can be scheduled. Business continues as if nothing happened. It’s the equivalent of a last-minute change in the path of a hurricane that sends the storm back out to sea.

Consider downtime and revenue implications for installation and maintenance

With traditional arc flash controls, commissioning and configuration are complicated, time consuming, and expensive. This introduces risk with the potential for improper configuration or missed settings that could reduce effectiveness and expose workers and equipment to hazards.

The costs for installation and configuration of traditional arc flash controls can easily swell, even in relatively straightforward systems, requiring resources with specialized skills and high billable rates to perform the work. ArcBlok dramatically minimizes these costs because it requires no commissioning or configuration, and it ships from Schneider Electric ready to use.

Maintenance, whether routine or in response to an incident, usually requires a worker to wear bulky personal protective equipment (PPE) based on the arc flash incident energy (AFIE) calculation. Donning a 40-calorie suit takes time. With the clock running, every extra minute costs money and productivity. Because bulky PPE is hot and difficult to endure, it cannot be worn for more than 30 minutes at a time. This adds even more time to complicated jobs that require workers to don and doff PPE multiple times. The AFIE for ArcBlok is only 1.2 cal/cm2, well below the 4 cal/cm2 limit for category 1 PPE. This translates to less monetary loss to downtime, less investment in PPE, and greater worker satisfaction because bulky PPE is uncomfortable to wear.

Factor in capital expenditure implications

As noted above, ArcBlok is a self-contained system that prevents arc flashes on the line-side of an electrical distribution system. This system simplifies the process of integrating safety into electrical design and eliminates the need for additional sensors, relays, or other arc flash protective devices on the line side.

In many cases, the incremental costs associated with ArcBlok are offset by savings in other areas of its system, especially if arc resistant switchgear is specified. And since ArcBlok is rated to extinguish five arc events, there is no need to replace the equipment after it does its job. It’s highly advanced technology that provides you with a simple solution to help keep your operations disruption-free from incidents that cause downtime and negatively impact revenue streams.

ArcBlok 2500 is compatible with most low-voltage switchboards and MCCs. To learn more about arc flash and the engineering controls designed to avoid, prevent, reduce and isolate the hazard, please download our whitepaper.


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