Cable cleat selection takes into account numerous factors listed below, and ideally if CMP Products can be supplied with the following: cable construction – type, ratings and diameter, system design, support structure and environment; it will then be possible to assist you with further advice on the correct type of cable cleat, and also the cable cleat spacing requirements for your specific application.
Cable – What type of cable is being used?
Diameter – The overall diameter of the cable will allow CMP Products to not only size the correct cable cleat, but it will also be required for calculating the short circuit forces the cable cleat maybe subjected to under fault conditions.
Performance – Does the cable have any fire performance (FR), or Low Smoke & Fume or Zero Halogen (LSF / LS0H / LSZH) requirements that the cable cleat would also have to adhere to?
Cable type – Is the cable a single core or multicore cable? What voltage is the cable? Low voltage (LV), Medium voltage (MV), or High voltage (HV).
Design – Overview of the cable management system
Mechanical load – what will the cable cleat have to support?
All CMP cable cleats having been tested for both axial and lateral loads, this will ensure they will be capable of supporting the weight of the cables(s).
Short circuit rating – What kA peak fault or RMS?
What is the maximum peak fault (kA) the cable may be subjected to under short circuit conditions? Based upon the specified cable the short circuit rating can be calculated with use of the standard IEC 61914:2009 to give the maximum forces the cable cleat will need to be able to withstand during a short circuit fault.
Cable configuration – Flat form / parallel or trefoil formation?
The cable configuration of the system will define the type of cable cleat required; either a single cable cleat, a trefoil cable cleat, a quad cable cleat, or this may even indicate that a bespoke cable cleat may be required which CMP Products will design, test, and certify to suit the cable management system requirements of its client.
Cable run length – How many cable cleats are required?
Whilst the spacing requirements for cable cleats will be subject to cable formation, cable diameter, and short circuit rating, the overall cable run length will give the correct number of cable cleats required for the installation. Cable runs that turn through 90° must also be noted as the cable cleat spacing will be reduced throughout these bends.
Single core cables expand and contract more due to temperature changes than multicore cables. If the cable is constrained, considerable forces can be transferred to the supporting structure. To allow for this, single core cables are generally “snaked” making slight loops to take up the expansion and contraction. It is also usual to allow some of the cable cleats to move freely and not restrain all cable cleats.