Trefoil Cable Cleats – Ellis Patents
Thorne & Derrick distribute Ellis Patents Trefoil Cable Cleats for single core cables on low, medium and high voltage electrical systems, typically distributing LV MV HV power including 3.3kV, 6.6kV, 11kV and 33kV voltages – we provide competitive prices for LV MV HV cable cleats manufactured by Ellis Patents from extensive stocks to UK and international destinations.
Trefoil cleats are typically used to clamp and support LV low voltage power cables 600/1000V (BS5467 | BS6724 XLPE SWA Armoured) to cable containment in electrical building services and substation installations.
To support and retain Transmission & Distribution cables in short circuit conditions providing electrical power distribution at 132kV 275kV 400kV in power tunnel applications a complete range of cable saddles are available for EHV Extra High Voltage cable support up to 162mm diameter in trefoil arrangement.
➡ The following Video produced by Ellis Patents demonstrates the safety and reliability of the Emperor range of trefoil cleats to retain 3 x single core cables in trefoil formation to the cable ladder when subjected to a 118kA short circuit.
Trefoil Cable Formation
Trefoil formation refers to a method of arranging Low Voltage (LV), Medium Voltage (MV) or High Voltage (HV) cables.
The trefoil arrangement is primarily used in situations where the three phases are carried by individual single core cables rather than a single three phase (or 3 core) cable.
In a 3 core cable since the individual conductors (copper or aluminium) along with their insulation (eg XLPE EPR) are placed near each other the net inductance is minimum as the magnetic field of the individual currents cancel each other out.
However, in single phase cables when the cables are placed in a straight line the inductance is not cancelled.
This can reduce the current carrying capacity of the LV MV HV cable by way of mutual inductance. It can also induce eddy currents in the cable sheath and metallic conduits which can cause heating. It is advisable to have conduits of non-ferrous metals.
Connecting the individual cables in the trefoil formation minimizes the magnetic field around the conductor and reduces the cable overheating.
All trefoil cable cleats have been tested in accordance with International Standard “Cable Cleats for Electrical Installations” IEC61914: 2015.
Overview of Trefoil Cleats
The following ranges of cable cleats for trefoil formation cables are all manufactured by Ellis Patents – should you require any further technical specification details on these brands of cleats please do not hesitate to contact us.
|Cable Cleat Type||Material||Short Circuit Protection||Min Cable Dia||Max Cable Dia||Fixing Holes|
|Alpha||Aluminium||73.4kA – 300mm Cleat Spacings||23.2mm||74.6mm||1 x M10|
|Emperor||Stainless Steel||235kA – 225mm Cleat Spacings||19mm||82mm||2 x M10 + 1 x M12|
|Vulcan+||Stainless Steel||132kA – 300mm Cleat Spacings||19mm||101mm||1 x M10|
|Atlas||Galvanised Steel||–||24mm||102mm||1 x M10|
|Colossus||Composite||104kA – 7.8m Intermediate Straps 1.3m||24mm||170mm||2 x M10 + 1 x M12|
|ProTect||Stainless Steel||136kA – 300mm Cleat Spacings||–||–||–|
Cable Cleat Short Circuit Testing
Contact T&D for further detailed information about short circuit testing (resistance to electromechanical force) – for IEC 61914 classification clauses relating to the performance of trefoil cable cleats with respect to temperature, UV resistance, corrosion resistance, impact rating, flame propagation, axial load rating, lateral load rating and cable cleat spacings contact T&D.
To protect and cushion cables during short circuit conditions the trefoil cable cleats are supplied with integral LSF polymeric liners.
➡ Contact us for customer service or technical support – see the full range of Ellis Patents Trefoil Cable Cleats below.