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Are there any special requirements for cables in wet or outdoor environments?

Categories: T&I  Traders and Installers 

Cables intended for use in outdoor environments should be adequately protected to withstand environmental conditions. In this blog, we’ll look specifically at wet and external environments.

24/11/2023 - 01:05 PM

Cables used in wet or outdoor environments require special considerations to ensure safety, durability, and optimal performance. These environments expose cables to moisture, temperature fluctuations, UV radiation, insect and rodent attacks, and physical wear and tear, making it crucial to choose the right cables for the job.


What cables should be used in external environments?

Any cables used in outdoor environments should have a robust insulation and sheathing. Outdoor environments can experience a wide range of temperatures, and so cables should be designed to operate within the temperature range specific to the location.

Additionally, outdoor cables may be exposed to mechanical damage from factors like vehicles, tools or even animals. Rugged cables with reinforced sheaths or armour are designed to withstand these challenges, reducing the risk of damage.

Steel wire armoured cable (SWA) is a common solution for outdoor applications. SWA cable can be a low voltage (LV) power cable or control cable that is designed for use in mains supply at maximum 600/1000 V and can be installed as direct burial, clipped direct and in cable ducts.

However, what happens if cables become waterlogged or are submerged as a result of flooding?


Waterlogged cables

In the case of waterlogged cables, our expert engineers say “Prysmian armoured cables (LV and MV with LSOH or PVC sheaths) are suitable for direct burial in ‘free draining soils’ as required by their respective British Standards. They are not recommended for installation in permanently waterlogged ground (in practice this is likely to occur in clay soils or below the water table). Such conditions may prematurely shorten the design life of the cable from our estimated 25 years minimum for a cable fully and continuously loaded in ‘appropriate’ conditions.” This applies to armoured LV cables BS 5467, BS 6724, BS7846, and also MV cables BS 6622 and BS 7835.


Download our guide to Waterlogged Cables.


A wealth of information can also be found on the Prysmian website, which includes a technical helpline and users can also ask a question via the web footer.


Flooded cables

In the event of flooding, our expert engineers recommend “to isolate the installation from the mains supply before attempting any assessment or remedial action on the flooded cables. For obvious reasons the sooner the flood recedes, and remedial action is taken the more likely it is that the cables will not be adversely affected. We would comment that there is a good history for cable reuse if the flood has receded within one or two days and the water is uncontaminated. In this situation we believe there will be little detrimental effect. Longer periods of submersion or where the water is contaminated with chemicals or effluent may be problematic.”

They also recommend that after cleaning and drying have been completed, “a full installation test to BS 7671 (IET Wiring Regulations) is carried out to the standard required on a new installation.”


Download our guide to Flooded Cables.


If the water is contaminated

Our engineers point out that the prevailing conditions do not include ‘contaminated water’. Where contamination is present further investigate may be required which could include chemical analysis of the surrounding soil. All sheaths as mentioned above may then be unsuitable.”  Further advice can be found in the guides above.


The Power of Prysmian

Investing in high-quality cables suited to their application and environment can lead to cost savings during the lifetime of the installation and help maintain seamless operations even in challenging conditions. Our range of power cables enable a wide range of applications, including indoor and outdoor installation for power distribution, lighting, plus plant and machinery.  Power your projects with Prysmian.


For more advice or technical support, visit our Technical Area or contact us today.