FEATURE CABLING & CABLE MANAGEMENT
EASY STEPS TO CABLE PROTECTION W
Tim Creedon, sales and marketing director at Flexicon, looks at the variables to consider when specifying cable protection
hen it comes to specifying cable protection, there are many
variables to consider. Should it be selected based on the likely temperature range, exposure to UV radiation, resistance to chemicals, or for specific fire performance, to name a few? The answer, according to Flexicon, is to
choose cable protection based on the full range of environmental factors, while also considering the wide variety of material types and properties now available to ensure that the system is fit for purpose. After all, cable protection should be designed to do just that; protect processes, performance and people, so taking time at the specification stage can save time and money further down the line.
WHICH CONDUIT? One of the first areas to consider is whether to opt for non-metallic (nylon), metallic or composite flexible conduit. Before the development of engineered
plastics, conduits and conduit fittings were made of metal. As plastics developed, they were used as sheathings to provide increased flexibility, plus improved water and corrosion resistance. With the development of high
performance engineering polymers, all-plastic conduits were developed together with injection-moulded conduit fittings, with nylon polyamide (PA) being one of the most important materials now available.
NON-METALLIC SYSTEMS With no exposed metallic content, non-metallic conduits do not rust or corrode, thus maintaining performance and appearance over time. They are
often quicker to install than metallic options as they are easier and faster to cut. Non-metallic fittings will typically be one piece and simply push on and twist to secure. Where fatigue life or impact resistance
is important, installers should consider nylon polyamide (PA) corrugated flexible conduits, which can offer high impact strength and recovery if crushed, combined with excellent temperature performance. Polypropylene and PVC conduits are
available but their suitability is limited, with both of these systems being inferior to nylon polyamide (PA) when it comes to temperature range fire performance, resistance to solvents and abrasion resistance. For installations subject to increased
ultraviolet (UV) exposure, it is important to consider that UV radiation will naturally degrade any plastic materials. Failure could result in materials cracking, an increase in brittleness, reduced flexibility and lower impact strength1
.
METALLIC AND COMPOSITE SYSTEMS Metallic systems are ideal for applications that require a very high compression or pull-off strength, or where there is the need to protect cables from exposure in hazardous environments. These systems typically have a higher level of crush resistance, high mechanical strength and can provide excellent EMC screening properties. Composite products, such as plastic
sheathing on metal conduits, metal over-braiding or metal threads on plastic fittings, can also offer the combination of light weight and high strength.
BESPOKE CABLE PROTECTION For more complex application requirements, customers should speak to their supplier to discuss bespoke options. These could include conduit supplied in
non-standard or pre-cut lengths, in larger or smaller diameters or with different thread termination or fitting options. Additionally, more complex requirements, such as altering performance characteristics to meet a certain temperature requirement, compression strength or abrasion resistance or to achieve a greater fatigue life may also be considered. The wide choice of systems now on the
market; whether for new installations or retrofitting are available for a reason - to ensure customers can specify the right product for the application demands. Installers should take time to consider all
factors rather than selecting flexible conduit based on preference or previous installation experience, to avoid over specifying or introducing unnecessary cost.
1
Manufacturers will often state that a product is UV resistant, but installers should ask for how long and look for guarantees of product performance. Flexicon, for instance, offers a solar warranty of up to 20 years
for selected products. 2
Alternative materials are available on request. Flexicon
8 NOVEMBER 2019 | ELECTRICAL ENGINEERING
RETROFITTING OPTIONS Many conduit system manufacturers are now developing enhanced retrofit options to make it easier and quicker to install cable protection. Flexicon, for example, offers its FPADS range of divisible corrugated conduits. Manufactured from two nylon (PA6) interlocking slit corrugated conduits2
, the construction
allows existing cabling to be inserted laterally via a slit opening. The two open conduits then interlock to form a protected IP40 system around the cables. This effectively means that the
customer can wrap a flexible conduit around the cables retrospectively with minimal disruption. It is also important to consider the
cable routing. Traditional split conduit options can potentially expose cabling when bent or routed around corners, whereas the FPADS option will maintain continuous protection of the cabling, irrespective of orientation or routing due to its interlocking design.
flexicon.uk.com
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