Before we start discussing solar cables, we need to understand solar photovoltaics. Humanity has been using renewable energy for longer than most realize. As early as the 7th century BC, people used magnifying glasses to enhance the sun's rays to start fires. As the energy crisis spreads around the world, people are looking for better and cleaner energy to replace fossil energy. As a new energy source, photovoltaics can better solve this problem.

History of Solar Technology

In modern times, solar energy is harnessed on a much larger scale. Today our solar cell technology has advanced by leaps and bounds. After 20 years of development, solar energy systems have become more and more popular and important worldwide. Solar cables are produced to match the entire photovoltaic system. Humanity will need to adopt modern solar technology - the technology required to harness electricity through the sun's rays - before reaching today's standards for solar cables and solar cables. Now let's take a brief look at the history of solar technology.

In 1839, French scientist Edmond Becquerel discovered the photovoltaic effect: the generation of a voltage, or electric current, in a material when exposed to light. Over the next century, scientists experimented with this concept and with light-sensitive materials such as selenium. In 1908, William J. Bailey of the Carnegie Steel Company invented a solar collector with copper coils and an insulating box that became the blueprint for the modern solar cell.

By 1950, three engineers at Bell Telephone Laboratories had created the first solar cell powerful enough to convert sunlight into standard electricity. Since then, scientists have continued to work on increasing the conversion rate, allowing us to use modern solar arrays to power specialty cars, airplanes and even entire buildings.

THHN Cable

For a long time, THHN wire was the solar cable used in photovoltaic arrays. Thermoplastic High Heat Nylon Coated (THHN) wire is a type of wire commonly used in construction. It is used in a wide range of industries and applications, and its heat-resistant properties make it more suitable for solar applications than other types of wire and cable. Historically, UF, SE and USE wires have also been used for various components and are included in the sections of the National Electrical Code relating to photovoltaic systems. As of 2008, NEC only lists PV Wire and USE-2 Solar Wire (usually dual rated as RHH/RHW-2 wire) as acceptable options. They are safer, stronger and more efficient.

USE-2 cable

Use-2 cables are regulated by UL 854. According to UL experts, it is generally chosen for underground applications, although according to Sec. it is also suitable for open air use. 690.31(B) of the NEC. USE-2 wire is rated to 90°C in wet and dry conditions, rated to 600 volts, and is more compressive and shock resistant than PV wire.

Dedicated photovoltaic wire

Due to the particularity of solar cables, this requires that our solar cables must have good insulation performance, otherwise it is impossible to predict potential damage. Secondly, the photovoltaic system will be exposed to strong sunlight, which requires our solar cables to be highly resistant to high temperature and ultraviolet rays. So a cable specialized in photovoltaic systems was developed and used.

PV Wire complies with EN50618 or UL 4703 standards. The PV wires are rated for 90°C in wet conditions, 150°C in dry conditions, and 1000V 1500V or 2000V. It can be used for underground laying or for grounded or ungrounded arrays. Often used in bare applications, it offers thicker insulation and sheathing, better resistance to sunlight, flame retardancy, and flexibility at low temperatures.

Today's Solar Energy System 

While USE-2 and PV wire were developed specifically for modern solar cable applications, other wire types used in the past are still useful in the solar industry. Wires like THHN can still be used in some PV functions as long as it is safe to do so. However, it should never be used to replace specified PV or USE-2 wires, as it does not include all of the dedicated features contained in PV and USE-2 wires, which could lead to failure.

Solar energy and solar cables have a very long history, although wiring standards have been around for a relatively short time. But we at Kuka Cable will continue to improve the solar process and the materials we use in array construction, providing professional cable solutions for photovoltaic systems.