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2014-10-13

Play it safe with Solar PV Cabling - Flexible Conduit for Solar PV installations

Too little attention is being paid to cable protection in solar PV installations warns Tim Creedon, sales and marketing director at Flexicon Ltd.   This could leave the installer liable for future maintenance and substantial fines due to an installation’s downtime.

 

Most PV installations are expected to last at least 25 years, so a great deal of care is taken when selecting the major components for solar PV, such as the PV panels, inverters and circuit protection.  Sadly cable protection is often an afterthought and this is big mistake.

Cable damage and degradation can affect the long-term viability of an installation and have serious safety issues.  All of this could leave the specifier and installer liable for future maintenance plus fines for lost revenue due to the installation’s downtime.

Solar PV installations are by their nature outside, which means that the cabling is potentially exposed to extremely harsh environmental conditions including UV, water and changes in temperature from below freezing to hot sunshine, plus a number of other hazards including rodents.

As an installer, you can protect individual cables on land or building based installations to some extent by securing them to the underside of panels or the mounting frames and ensuring that they are individually isolated in a DC combiner box.  There are however, a number of areas where you need to group cables together, where you need an alternative to tie wrapping and also areas where it is not sheltered.

For these areas a carefully specified conduit system will provide extra protection.   A cheap option is a false economy because it will fail, leading to disruption and downtime.

Take UV protection.  Over time ultraviolet light will degrade plastic materials such as the insulation on cables or on the conduit protecting them.   This will result in lower impact strength, less flexibility and possible cracking and a lower fatigue life.  You only need to look at the emphasis cable manufacturers place on the UV performance of solar cables to realise this and the same care needs to be taken when specifying flexible conduit.

We would always recommend using a black product, as the carbon black additive inside the material will protect against UV.  For peace of mind ask the manufacturer for independent test reports demonstrating the product’s UV resistance.

Exposure to water is another hazard, so you need to consider the IP rating of any system and make sure that you use the appropriate fittings.

The installation will also face extremes of temperature from below freezing in the winter to high temperatures in the summer; this causes materials to age more quickly and also causes them to expand and contract, potentially leading to the build up of condensation.  Many materials are also more brittle at colder temperatures, leaving them more vulnerable during impact.

Other hazards due to the climate may include wind, dust, lightning and for coastal installations the corrosive affects of salt-water spray on metallic components.

The location of a PV installation will also introduce other potential hazards.  A risk analysis for a solar farm on land will reveal that cables need protecting from site maintenance such as strimmers, from grazing animals and also from vermin attack.  Cable theft in remote locations is another factor.

Selecting the most suitable conduit system for long term external installations requires a thorough risk assessment.  Get it right and you will prolong the life of the cabling and even more important protect people from electric shock.  It is not a good idea to try and take shortcuts with such protection.

When so much is at stake, it pays to seek technical advice from a manufacturer that you can trust.  Cheap imported conduit is not an answer, you need to select a system that will withstand a wide range of hazards to ensure prolonged cable life and look for guarantees of performance from a manufacturer who can support any claims.

Contact us now for support and guidance regarding protecting your vulnerable cables for Solar PV installations - sales@flexicon.uk.com

 


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