Idea to Innovation: Inventions that Move the Industry
From the first product, a panel conduit that led to the name Panduit, we understood our engineers are the gateway to success and need free reign to investigate and innovate. This is one of their stories.
Cable Cleats: A Story of Higher Standards for Short Circuit Protection
Before protection devices have time to react, an industrial short circuit event can release a tsunami of force. In a millisecond, the damage has been done; with electromagnetic force ranging upwards of 10,000 pounds, the damage can be significant.
As the complexity of industrial engineering and construction projects grows, it’s imperative that design engineers and contractors know how to design electrical systems that meet project specifications and budget constraints without shortchanging safety protections for the people and equipment involved. For EPC companies looking to provide their clients with a truly complete solution, cable cleats are a critical element to include in electrical system design.
Short circuit events can occur at any stage of a project, resulting in downtime, rework and potentially deadly injuries to nearby workers. Engineers must be able to trust that the cable cleats they’ve chosen can withstand the stresses created by peak fault currents. That’s why our engineers advocate for comprehensive cable cleat safety standards and are determined to design cable cleats that not only met those high standards but exceed them.
An Undefined Standard
NEC standards require that cables be secure enough to prevent excessive movement due to fault current magnetic forces—but when it comes to routing cables in a cable tray, it doesn’t specify how to design the proper containment system to meet those forces.
Balancing Design Flexibility and Risk
Both NEC and IEC standards require cables to be secured against short circuit events. But since cable trays have only recently gained popularity in North America, current NEC standards require protection be installed but don’t include recommendations on cable cleats.
Cable tray applications are more common in Europe and the IEC standards have evolved to include a robust methodology for testing cable cleats against short circuit events. IEC 61914:2015 sets standards for resistance to electromechanical forces, but also outlines requirements for temperature rating, corrosion, UV resistance, and more to ensure cable cleats can withstand harsh construction site conditions.
We take pride in our leadership on industry standards. This is one of the many ways Panduit ensures solutions remain on the cutting edge of compliance and safety. Panduit’s technical engineer Andy Booth recently joined the IEC committee as the US expert, responsible for overseeing the IEC 61914 standard on cable cleats for electrical installations.
Panduit is constantly advocating for the adoption of these stronger standards, and only recommend applications that meet them. Engineers like Booth and Rodney Rouleau, our senior engineering manager, believe that ongoing harmonization will eventually bring NEC and other regional codes closer to the IEC. So, they were determined that our cable cleat designs would meet those standards from the start.
By allowing engineers to verify design changes and predict peak current certification levels, the simulation significantly reduced the prototype-and-test cycle. During the process, the team realized another way they could help design engineers: by developing a mobile app to speed up the time-consuming calculations needed to determine the correct cleat for a specific cable size and current. The result was Panduit’s Cleat kAlculator™.
A Model Cable Cleat
Knowing center to center distance between the conductors and peak short circuit current, it’s easy to determine the potential force of a ground fault. But the short circuit force formula is just a starting point. During a ground fault, forces are instantaneous and oscillating wildly, moving components at velocities up to 2,000 inches per second; conditions that cannot be replicated by the relatively slow and controlled force of a mechanical tensile test. With that in mind, engineers took a different approach: using state-of-the-art ANSYS simulation software to develop multi-physics model of the dynamic forces that occur during a short circuit event. In addition to being able to adjust the stiffness, yield strength, and mass of conductors, the award-winning simulation included high strain-rate material models for each component and element erosion criteria to account for material deformation and catastrophic failure.