• • • ELECTRIC VEHICLES • • •


Protecting cabling for the EV charging network


Under new laws planned by the Government, rapid charging networks for electric vehicles will need to have a 99% reliability rate, with plans in place to support the UK market to reach 300,000 charge points by 2030, says Alex Smith, technical director at flexible conduit manufacturer, Flexicon


often out of service. M


There are many cable protection considerations for electrical contractors, considering areas such as resistance to compression, speed of installation, material specification and ingress protection (IP) ratings.


Protecting electrical cabling for longevity


The correct solution can be instrumental in protecting uptime and avoiding unnecessary cost. Cable protection should be specified as a complete end-to-end system, considering not only the flexible conduit used, but the range of termination and fittings used too.


One of the first areas to consider is the range of external hazards that the cables and infrastructure may encounter. In most applications, the EV charging point will be installed outside and exposed to the elements, with the electricity supplied through cables running underground. These cables will typically be buried in concrete, with a platform or pre-cast slab supporting the charging point above. The flexible conduit solution specified must therefore have excellent resistance to compression, as well as considering the highly corrosive nature of the concrete itself. Polypropylene conduit can be an ideal option in this scenario, as opposed to metallic systems. With high impact strength and abrasion resistance, the material also provides good electrical insulation and weathering qualities. Of particular importance is the conduit’s resistance to corrosion. This can occur if the concrete starts to degrade through exposure to chlorides present in water or through carbonation, which affects the natural alkalinity of the concrete. Polypropylene conduits, such as Flexicon’s FPP system, are proven to offer excellent chemical resistance, particularly to aqueous solutions of alkalis and salts present in this scenario.


Ingress protection


The network of public EV charging points will also be subjected to a range of other environmental factors.


Exposure to water ingress and extreme temperatures are commonplace and the effects of these can result in premature product failure, which in turn leads to increased downtime and operating costs.


The BS7671 18th edition wiring regulations


specify that socket outlets should be placed at a height of 0.5 to 1.5 metres from the ground. To


electricalengineeringmagazine.co.uk ELECTRICAL ENGINEERING • FEBRUARY 2023 43


otorists continue to express frustration with the lack of reliability and accessibility, with many charge points


are required, nylon systems could be used to achieve IP66, IP67, IP68 and IP69 performance.


Retrofitting options


As the EV charging network becomes more established, installed units – and their electrical cabling – will require routine maintenance to ensure ongoing reliability.


This may require cable protection to be upgraded; traditionally a complex and lengthy task, with the installer required to pull existing cabling through the open end of a conduit system. Divisible conduits, such as the new Flexicon


FPADS range, are now making retrofitting much simpler. They allow existing cabling to be inserted laterally via a slit opening, which then interlocks to form a protected IP40 system around the cables for enhanced mechanical protection.


Building a resilient network for the future


prevent external influences, cable protection could be added to enhance protection in the presence of water or solid foreign bodies above the IP44 minimum requirement. If specified correctly, there are a range of suitable flexible conduit system alternatives that can offer effective cable protection. Basic cable protection can be achieved with Flexicon FPP conduit combined with Flexilok (FLK) fittings providing IP66 levels of protection. For high-risk locations or environments where enhanced IP levels or temperature performance


As well as protecting the electric cabling running underground, it is likely that flexible conduit suppliers will play an increasingly important role in protecting the electric cables within the charging unit itself, working alongside manufacturers and OEMs.


Composite products such as plastic sheathing on metal conduits to increase the ingress protection, or metal over-braiding on non-metallic corrugated for EMC, or metal threads on plastic fittings can offer the ideal combination of light weight, high strength, and fast installation.


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