How to Select the Right Cable Cleat

Choosing the correct cable cleat to protect your project will assure optimal performance, reliability, and quality. Panduit has solutions to suit a variety of environmental conditions, industrial applications, and short circuit fault current requirements.

Having the right cable cleat provides restraint and protection in the event of a short circuit fault. Panduit has developed the Cleat kAlculator™ to help engineers, designers, and installers determine the correct cable cleat for their application.

To simplify this selection decision, three easy steps allow users to:
  1. Select a cable layout
  2. Input cable outer diameter
  3. Input peak short circuit current

The Cleat kAlculator™ is available for download in the Apple Store
or Google Play.

When Selecting Cable Cleats, Consider a Variety of Factors

Cable Layout: How the cables are arranged and secured will determine which cable cleat fits them best.

Cable Outer Diameter: The diameter of the cable determines what the correct size of cleat is and is also required for calculating the short circuit forces the cleat could face.

Peak Short Circuit Current Rating in kA

Cable Tray Rung Design and Spacing

Environment Performance: The cable cleat should have the material and specification features needed for it to withstand the elements it will face. Examples include flame rating, extreme temperatures, or chemical and corrosion resistance.

Using this data, force between conductors during short circuit event can be calculated and the correct cleats at appropriate spacing can be determined. Cleat spacing is always a function of the peak kA, distance between the centers of neighboring conductors, and the rated strength of a cleat.

NEC 392.20(C) and The Cable Tray Institute provide guidelines for securing cable on horizontal and vertical runs, but cable cleat spacing is determined by the calculated forces during a short circuit fault. For horizontal, vertical and radius sections of the cable run, additional cable restraints beyond the minimum cable cleat requirements may be required for proper cable management. 

Panduit’s extensive line of cable cleat solutions provides various options to fit the needs of the project and provide job productivity, reliability, and safety. Panduit recommends the following solutions: stainless steel locking strap cleat, stainless steel buckle strap cleat, stainless steel trefoil cleat, and aluminum and polymer cleats. These cable cleats are designed to perform in a wide range of harsh environments, reduce material cost, and reduce installation time.

Lab tests performed on Panduit cable cleats verify strength of cleats and provide a baseline rating, in addition to being validated at a third-party test facility to ensure they perform to specifications when needed.

The simple and intuitive design leads to increased productivity, and they are compatible with a variety of ladder racks and cables.
To learn more about Panduit’s line of Cable Cleats and to download the The Cleat kAlculator™ visit Panduit.com/cablecleat

Short Circuit Events and the Havoc They Wreak on Infrastructure Projects

Why NEC 392.20(C) leaves you unprotected

There are many ways for a short circuit fault to develop, and they can happen anywhere along the electrical distribution system. Short circuit faults occur when an abnormal connection between two nodes of an electric circuit is made.

During a short circuit fault, maximum electromechanical stress between conductors occurs at or before 0.005 second. Current levels in these events can range upwards of 200 kA. In the worst case of a 3-phase short, magnetic field induced repulsive forces between the cables can range upwards of 10,000 pounds.

When a short circuit fault occurs, tremendous magnetic forces repel the power cables from each other resulting in violent forces that damage everything in their path. Typical circuit breakers and other protection devices trip and interrupt a fault between 0.06 to 0.1 second, leaving just enough time for substantial damage to occur.

Cable cleats reduce damage and rework by performing their function within those first 0.005 second (i.e. at peak kA) before a circuit breaker trips and interrupts a fault, making them the best option for short circuit mitigation.

Without the use of a cable cleat system, there is no protection for the employees or equipment in a facility when the short circuit forces are at their peak prior to a circuit interrupter engaging. To avoid potentially severe damage to the facility and infrastructure, as well as personal injury, cable cleats are used to restraint cables during short circuit events.

Cable tray systems provide more design flexibility and can be easier to install than traditional pipe and wire but must be properly engineered for protection against short circuit faults. Cable tray applications are only a safe and viable solution when paired with the right cable cleat.

Specifying and installing the right cable cleats when electrical infrastructure is first established is paramount to setting projects up for success. While metal conduit is often used in several areas of a project to distribute power, it is also often distributed by cables in a cable tray system.

In the U.S., NEC 392.20(C) is the National Electrical Code that governs the safety of the cable installations in cable tray. NEC Article 392.20(C) states: “Parallel connected single conductor cables shall be securely bound in circuit groups to prevent excessive movement due to fault current magnetic forces.”

While NEC 392.20(C) includes language for securing cables during a short circuit fault, it does not specify how to design the proper containment system to meet those forces. Often the lack of clear guidelines on short circuit protection in the NEC results in inadequate or no cable containment
to protect against short circuit events in tray cable installations. Europe has been utilizing cable tray systems for several decades and leads the industry in design standards and best practices.

As such, the IEC 61914:2015 standard provides the testing methodology and process to ensure reliability of cable cleats and ultimate protection in the event of a short circuit event. Cable in cable trays are only a safe and viable solution when paired with the right cable cleat solution to protect against short circuit events.

Unfortunately, NEC 392.20(C) does not currently provide specific guidance on how to securely contain cables in the event of a short circuit when routing cables in a cable tray. To protect the electrical infrastructure when using power cables in a tray, installing an IEC 61914:2015 compliant
cable cleat is the best option when protecting against a peak short circuit fault.


To learn more about Panduit Cable Cleats, visit www.panduit.com/cablecleat

Panduit Innovation Recognized with 2019 ANSYS Hall of Fame Award

Panduit is built on a foundation of innovation, and our unwavering commitment to excellence in product design and performance was recently recognized with a Best in Show, Commercial category, in the 10th annual ANSYS 2019 Hall of Fame competition.

ANSYS, a global leader in engineering simulation software, conducts the Hall of Fame competition to highlight how engineers are solving key challenges with ANSYS Pervasive Engineering Simulation solutions across numerous industries. Panduit was one of three companies recognized in the Commercial category.

Panduit’s winning entry showcased how Panduit engineers optimized the design of high voltage cable cleat products to prevent the substantial damage that can occur before circuit breakers react to a short. The entry also highlighted how Panduit achieved significant cost and time savings for its latest line of cable cleat products.

View the video to learn more about our simulation testing model for innovative Panduit cable cleats.

Advanced R&D Solutions for Product Design

Cable cleats are needed to restrain high voltage cables during short circuit events. Current levels in these events can range upwards of 200,000 Amps. In the worst case of a 3-phase short, magnetic field induced repulsive forces between the cables can range upwards of 10,000 pounds and develop within 1/100th of a second. Substantial damage can occur before circuit breakers can react to the short. Cable restraint is critical to protecting personnel and infrastructure as well as reducing downtime.

Using state-of-the-art simulation software, Panduit’s engineers modeled this highly dynamic, multi-body contact, 3-phase alternating current short circuit test event that occurs over a period of 1/10th second (ref: IEC 61914:2015), can develop component velocities of more than 2000 inches/second, and exhibit high material deformation and catastrophic failure. Significant simulation development milestones included:

  1. Adjusting the stiffness, yield strength, and mass of solid copper conductors to behave like stranded conductors at the prevailing temperatures
  2. Developing high strain-rate material models for each component
  3. Integrating the electro-magnetic solution capability into the simulation
  4. Development of a 30-variable mathematical model to exactly match the short circuit test current pattern and using a genetic algorithm to find the variable coefficients
  5. Developing element erosion criteria to enable simulation of physical failure
  6. Successful verification in early testing

The new cable cleat product lines were originally certified in testing very near the peak short circuit current levels predicted by the simulation. The understanding of the variables involved in the 3-phase short circuit event and repeated simulations to verify design changes and predict peak current certification levels in testing resulted in a substantial reduction in the prototype-and-test cycle.

To find out more about Panduit’s legacy of innovation and our future-forward network and industrial electrical infrastructure technologies, visit our research and development section on panduit.com.