General Information
June 8, 2015 7:30 am
Talon® cable cleats secure cables subject to lateral and torsional forces and provide axial strain relief for vertical and horizontal cables. Typical installations benefiting from Talon® cable cleats are: Low, medium and high voltage, ac and dc systems Single-conductor cables, including single cable and bundled cable configurations (e.g. trefoil, quad, etc.) Multi-conductor cables susceptible to “through-faults” Cables in extreme environments (e.g. arctic, desert, high altitude, offshore/marine, tropical, underground) Cables exposed to aggressive forces (e.g. short circuits, cyclical loading, high-shock, pulse loads, seismic movement, vibration) Vertical cables requiring strain relief and long straight cable runs (esp. cables in cable tray or... View Article
October 9, 2014 6:07 pm
LINEAL SPACING Lineal cable cleat spacing decisions are based on the dynamic electromechanical forces between cables, cable deflection, axial retention (i.e. strain relief) requirements and the geometry of the cable support system. Talon Products is pleased to assist with cable force calculations utilizing our proprietary software. The results of the force calculations will allow customers to choose a lineal spacing that fits their unique application. CAUTION: Some cable cleat spacing charts may only consider the results of the IEC 61914 static cable cleat lateral resistance test, which (in the case of non-rigid cable restraint designs) may include severe cable cleat deformation. Others may... View Article
October 9, 2014 5:52 pm
While the terms clamp and cleat are sometimes used interchangeably, they are governed by different standards with exclusive, but analogous test protocols (see FAQ-10). The most important consideration when evaluating cable restraint products is to ensure the testing is applicable to cables (not pipe or conduit) and is performed under conditions that are at least as demanding as the intended usage. Talon® cable cleats have passed rigorous 3rd party testing in accordance with ASTM B117, IEC 60695, IEC 61914, ISO 4892-2, UL 94 and UL 2239.
August 27, 2014 7:12 pm
IEC 61914 EDITION 2.0, 2015, CABLE CLEATS FOR ELECTRICAL INSTALLATIONS The international cable cleat standard IEC 61914 provides testing criteria and requires cable cleats to protect the cables during short circuit testing. To comply with the standard, products must pass tests for resistance to flame propagation, impact and ultraviolet light exposure, as well as for lateral retention. The standard includes optional tests for axial retention and resistance to electromechanical forces. The president of Talon Products, Charles Darnell, a Registered Professional Electrical Engineer, IEEE Senior Member and member of ANSI US National Committee of the IEC is the US Representative to the... View Article
August 27, 2014 7:12 pm
While circuit breakers and fuses can provide thermal protection for the cable insulation, they are unable to protect cables from mechanical damage. Even with overcurrent protection devices that offer an “instantaneous” protection setting, irreversible cable damage will typically occur in inadequately restrained cables within the first half cycle of the fault initiation (i.e. before circuit breakers can interrupt the fault). In the case of fuses, the restraint system must withstand the forces associated with the maximum let-through current. In most cases, overcurrent protective devices for power cables are adjusted with intentional time-delay for system coordination with downstream devices, which increases the potential for mechanical damage in inadequately restrained cables.... View Article
August 27, 2014 7:11 pm
The Lorentz Force Law may be used to calculate the electromechanical force between conductors, as follows: F/l = μ0 * i1 * i2 / 2πs Where: F/l = Distributed force between conductors F = Electromechanical force l = Lineal spacing between cable restraints μ0 = Magnetic permeability constant i1 = Instantaneous current magnitude in conductor #1 i2 = Instantaneous current magnitude in conductor #2 π = pi (mathematical constant representing the ratio of a circle’s circumference to its diameter) s = Spacing between conductor centers Most alternating current short circuit waveforms involve asymmetry due to transient and subtransient reactance, as well as unidirectional... View Article
August 27, 2014 7:11 pm
Since alternating current follows a repetitive oscillating (sinusoidal) pattern, short circuit current produces alternating attractive and repulsive forces between conductors. These dynamic electromechanical forces are constantly changing in magnitude and direction and can exceed 40 kN/m (2,741 lbf/ft). Even when the short circuit current is quickly interrupted, it is important to recognize the maximum electromechanical forces typically occur within the first half cycle, which is long before a circuit breaker can open. During a short circuit, the high current flowing through the conductor’s resistance rapidly heats the cable, resulting in axial (longitudinal) and lateral (radial) thermal cable expansion. The combination of thermal... View Article
August 27, 2014 7:10 pm
One characteristic of non-rigid cable restraints is their increased propensity to deform under mechanical stress. Cable restraints, including cable cleats, are classified as “non-rigid” when manufactured from ductile materials (e.g. metal banding) that can deform significantly and permanently when exposed to static or dynamic cable forces. The left photograph demonstrates the severe limitations of non-rigid cable cleats. Cable cleats classified as “rigid” retain their physical shape when exposed to static and dynamic mechanical stresses. Rigid cable cleats are typically manufactured from non-ductile materials (e.g. heavy metallic cross-section or reinforced thermoplastic). Thick stainless steel cross-sections are impractical due to high cost and other metals are unrealistic due to localized induction heating, corrosion susceptibility and/or poor product designs. ... View Article
August 27, 2014 7:09 pm
Cable cleats are required for the securing and retention of cables. This protection is especially important when cables are exposed to axial, lateral or torsional forces, such as those caused by the weight of cables in vertical runs or short circuit fault currents. From a regulatory compliance perspective, proper cable retention facilitates conformance to electrical installation standards. For example, NFPA-70-2017, The (US) National Electrical Code, NEC Article 392.20 (C) requires single conductors to be “securely bound in circuit groups to prevent excessive movement due to fault-current magnetic forces.” In that same Code, Article 110.36 requires insulators used as supports for... View Article
August 27, 2014 7:06 pm
A cable cleat is a cable restraint device (sometimes called a cable block, cable bracket or cable clamp) that is designed and tested to provide securing and retention of cables. A cable cleat is typically fixed to a mounting surface (e.g. ladder-type cable tray rung) and fastened around one or more cables. According to IEC 61914 and UL 2239, neither conduit clamps, P-clamps or cable ties are considered to be cable cleats. Cable cleats may be applied to single conductor or multi-conductor cables. In addition to securing cables subject to axial, lateral and torsional forces, Talon® cable cleats provide strain relief... View Article
