You can call the solar cable and wires veins and arteries of the solar photovoltaic system. Frequently power is not used near the point of its generation i.e., PV solar panels. For the transportation of electricity, solar cables are required. Before going into the details of solar cable types, you must know the difference between the Wires and Cables.
You might hear both words for the same thing, and it might confuse you. But actually, cables and wires are entirely different from each other. A single conductor is present for a solar wire to transport electricity, whereas solar cables contain multiple conductors inside the insulated jacket. You can call the wires the component of cables.
Similarly, the difference between solar cable and normal cable is the insulation part. The normal cable insulation is made of PVC where the solar cable insulation is made of XPLE material. Therefore the life span of solar cable is about 25 years and that for DC cable is about 8 years. XPLE insulation can withstand the environmental factor as compared to PVC insulation.
Solar Cable Types for PV Installation
The cable has three or more than two insulated wires, which are enclosed in one cover. Cables are divided into different types based on the number of wires encapsulated together in the jacket and the diameter of the wires used in it. Also, the type of materials it is made with. SolCable 6mmare divided into two basic modules solar Direct Current power cables and Alternate Current connection link cables. There is a major use of cable 6mm and cable 4mm.
DC Solar Cable Types
These are divided further into two types
- Module cables
- String cables
These cables are equipped with appropriate connectors and are integrated into PV solar panels. Positive and negative cables are connected to the producer box or straight to the solar inverter through special extension cables. Cables of different cross-sectional areas are used depending upon the module’s output, i.e., 6mm2, 4mm2, and 2.5mm2. Positive and negative wires are not placed in one cable to guarantee earth error and short-circuit.
For high-reliability single mode wire cables with double protection are preferred. The DC cables are used outside. Solar cables are usually two-core cables between the main supply and also amid the generator assembly box and solar command inverter. Live wire usually red in color, and a negative wire mostly in blue color is typically surrounded by an insulation layer. For establishing a connection between the solar power inverter and PV Strings, three types of systems are designed:
- Direct Connection
- Photovoltaic system with DC link Box
- Node String system
AC Connection Cable
There is a difference between connection and power supply. AC connection cables connect the electricity grid to the power inverter through protection equipment. Five-core AC cables are used for three-phase inverters because the assembly is between the small voltage grids. In five-core AC connection cables, there are three alive wires to carry the current through three phases. A neutral wire that carries the current towards the opposite direction from the device or source. And a ground wire, also known as safety wire, links the covering of the device to the ground.
For the single-phase system, three-core AC cables are used. Which contain three types of wires that is a ground wire, a neutral wire, and a live wire. For the establishment of secure and safe connections, national codes and rules are needed to be followed.
Size Selection for Different Solar Cable Types
The solar PV system requires an accurate and correct size while making a connection of its various components with the solar cables. It is done to ensure the risk of overheating and energy loss. A short-sized cable can impose a possible risk of triggering a fire due to high temperature but is also a code defilement in most authorities. There are some aspects that help to determine the size of the solar cables. Let’s have a look one by one.
The size of wires and cables depends upon the following factors:
- The producing capacity of the Solar Panel. As the amount of electricity production is directly proportional to the size of the wire used, so higher the electricity produced, the larger the size.
- The distance between the load and the solar panel system. Also, the distance and size of the solar cable are directly proportional to each other, hence larger the distance, greater the size.
Which cross-section cable should be used for the direct current? The answer is quite simple. Solar panel wire types 6mm and 4mm are widely used. The inverters must be fixed as near to the load as possible. Because the faults produced by the AC side are higher than on the DC side.
The direct current produced from the photovoltaic solar panels should go to the extent that is possible without damages to the solar supply inverter. Damage is unattainable because each cable has a very low resistance at room temperature. The DC solar cable design should be like that; its loss is as small as 1% of the photovoltaic producer peak output.
Quality Selection of Solar Cable Types
Well! The quality of solar cables depends on a number of factors. Here will see some core valued features that enable a solar cable to be perfect for use.
A good solar cable is always climate, ultraviolet, and ozone resistant because the solar tows are used outside the buildings mostly and remain exposed to sun and air humidity.
Heat Bearing Capacity:
Preferable solar cables are so designed that they can bear high temperatures easily. These must be appropriate for high temperatures ranges from -40 degrees centigrade to 90 degrees centigrade.
Malleable and Ductile:
It should be able to withstand high mechanical stress like tension, shear load, and bending.
Reliant on the type of use, it should have a high dielectric constant.
Nonflammable and Free from Halogen:
Solar cables that are free from halogen have a better-quality performance in the case of catching fire. A good solar cable must not trigger a fire.
Have small outside diameter:
Optional strengthening is also required to protect against marten, rodents, and termites.