The solar industry is seeing a sharp rise in unsafe and non-compliant wiring practices as some installers and suppliers continue using standard AC power cables in photovoltaic (PV) solar installations.
South Ocean Electric Wire (SOEW), an Alrode-based JSE-listed cable original equipment manufacturer (OEM), is warning that the use of standard cabling in solar installations can lead to serious risks, including overheating, insulation failure, fires and costly system breakdowns.
“A solar installation costing hundreds or even millions of rands could be severely compromised with ordinary cabling, with the faults sometimes only becoming apparent after a few years,” explains Andre Smith, CEO at South Ocean Electric Wire (SOEW).
“One of the criteria we recommend is that solar cabling should be rated at 1,500/1,500 V DC and able to be used in systems rated 1,800/1,800 V DC as per SANS 62930. It should be noted that PV cables are DC-rated, whilst normal power cables are AC. AC cables are rated 600/ 1,000 V but AC cables have no 1,000/ 1,000 V rating.”
Can normal cables be used for solar power systems?
Smith notes that using regular electrical cables instead of PV cables for a solar installation is not recommended. PV cables are specifically designed to meet the unique demands of solar systems, including UV resistance, weather resistance and high-temperature tolerance. Regular electrical cables may not possess these characteristics and could lead to safety hazards, decreased performance, and reduced lifespan in a solar environment.
What is the difference in conductivity between PV cables and normal cables?
He adds that PV cables often utilise flexible tinned copper conductors with high conductivity. The tinning process enhances the copper’s conductive properties and minimises the risk of oxidation. Tinning promotes soldering when required. Normal cables may either use copper or aluminium conductors, with copper being the more conductive of the two. Copper conductors offer superior electrical conductivity compared to aluminium conductors, but also come at a higher cost.
What are the key characteristics of a high-quality PV cable?
“PV cables have insulation materials specifically engineered to withstand prolonged exposure to sunlight, temperature variations, and harsh environmental conditions. This insulation provides protection against UV radiation, ozone resistance, moisture and abrasion, ensuring long-term performance and cable durability. The insulation is normally cross-linked Low Smoke and Zero Halogen (LSZH), these properties are designed to enhance safety in case of fire,” Smith notes.
Special connectors
“In addition, PV cables use special connectors designed and engineered to guarantee proper and secure connections that minimise voltage loss, heating, water ingress and disconnection. The outer diameter of the cable is critical to the connector; it is therefore not recommended to use an ordinary power cable.”
Cable cost
Smith argues that PV cabling costs more than ordinary cable due to its additional properties. But in the long term, it will last longer than ordinary AC power cabling.
Compliance with the standard
“Compliance is a key in selecting the correct product. Solar cabling needs to meet both TUV and SANS IEC 62930 standards, which include testing under all different operating conditions. This guarantees safety, reliability and performance in every installation.
“Each cable produced at SOEW undergoes compliance testing internally by our laboratory personnel who have over 28 years of cable testing and quality assurance experience as well as external SANAS 17025 accredited laboratories testing to give our clients and installers assurance that we go beyond standard certification requirements.
“Our cables are marked with SANS 62930 IEC 131, which denotes that the insulation and sheath both include cross-linked LSZH insulation, which provides properties designed to meet enhanced fire safety compliance,” Smith concludes.
