On a technical level, today's innovations in compounds and extrusion processes can help cable manufacturers meet the unique specifications of the solar industry. Numerous cable manufacturers are working closely with project designators to produce pv1-f solar cable that meets the design requirements.
Photovoltaic cable installation
In order to produce cable products that can meet the requirements of solar photovoltaic systems, the design shall meet the requirements of IEC 62930: ED 1.0:2017 and BS EN 50618:2014. We'll explore these specific requirements in further detail next, with each standard placing a different emphasis on certain materials.
The first requirement is for cable products used with secondary equipment. Secondary equipment is defined in IEC 61140 as double-insulated equipment that does not require safe grounding, and is typically suitable for electrical appliances such as television sets, DVD players and power tools. BS EN 50618 is suitable for testing these types of cable products; however, IEC 62930 makes no provision for this. Therefore, any appliances using photovoltaic cable products with secondary equipment should be tested in accordance with BS EN 50618.
A supplementary consideration in seeking to understand specific characteristics and the emphasis of each standard is the size of the conductor. BS EN 50618 only specifies a conductor size range of 1.5 to 240m2, while IEC 62930 allows a larger range of 1.5 to 400m2. It is essential to note that even if the diameter of the cable product is large, the conductor size may be tiny due to being surrounded by insulation, pads, and steel wire armor. Therefore, deciding which standard cable products should be tested should not be based solely on conductor size.
The main difference between the standards is the materials that are allowed to be tested, for example BS EN 50618 only allows testing of cable products manufactured using LSHF materials. These types of cable products release minor smoke and corrosive gases in the event of a fire. They are frequently designated for use in public buildings because they reduce the risk to public safety. In contrast, IEC 62930 allows testing of materials with or without LSHF, including pvc cable products. When this material burns, it will produce thick smoke and toxic fumes. PVC or modified PVC is more suitable for customer requirements. For example, PVC cable products may be better suited for transporting electricity from solar panels to water treatment facilities because they have higher chemical resistance than LSHF products.
As part of IEC 62930 and BS EN 50618, heat resistance testing is mandatory. The test was designed to determine the service life of the cable and included testing any photovoltaic cable product at temperatures up to 120°C for up to 20,000 hours to simulate the performance of the product in operation. When these standards were first developed, thermal durability tests caused some controversy, as their main measure was to demonstrate how lengthy the cable would operate before reaching a specified threshold; all of these tests were conducted under controlled conditions. Because many PV cable products are installed under extreme conditions, the results of this test may not be as conclusive as other mature tests, such as thermal pressure tests used to check whether sheathing and insulation withstand pressure at elevated temperatures. Nevertheless, cable products submitted for heat resistance tests may greatly assist in proving cable quality.
While cable products can successfully pass heat resistance tests, consideration should also be given to how additional characteristics will be affected by their operating conditions. For example, solar panels are frequently installed in coastal or desert areas where temperatures can drop rapidly, which can cause cables to crack or bend as temperatures drop below the temperature values these cable products are designed to work at. If cable products are manufactured using poor quality materials, they may absorb large amounts of moisture and degrade the performance of cable products by reducing the amount of current they can carry. These examples demonstrate the need for extensive performance testing of photovoltaic cables to verify the quality and suitability of installation under prescribed conditions.