Wire types vary in conductor material and insulation:
Aluminum or Copper: The two normal conductor materials utilized in commercial solar installations are copper and aluminum. Copper has a more prominent conductivity than aluminum, thus it carries more current than aluminum at a similar size.
Aluminum might be weakened during installation particularly during bending, however it is less expensive than copper wires. It is not used (not permitted) for interior home wiring, as they are used in larger gauges for underground or overhead service entrances and for commercial operations.
In most cases, the solar wire used in solar power stations are used for outdoor long-term work. Due to the limitation of construction conditions, connectors are mostly used for wire connections. Wire conductor materials can be divided into copper core and aluminum core. Copper core wire has better oxidation resistance than aluminum, long life, good stability, low voltage drop and low power loss; in construction, because the copper core is flexible and the allowable bend radius is small, it is convenient to turn and pass through the pipe; and the copper core is resistant to fatigue and repeated bending is not easy to break, so the wiring is convenient; at the same time, the copper core has high mechanical strength and can withstand greater mechanical tension, which brings great convenience to construction and laying, and creates conditions for mechanized construction. On the contrary, aluminum core wires are prone to oxidation (electrochemical reaction) in the installation joints due to the chemical properties of aluminum materials, especially creep phenomena, which can easily lead to failures.
Therefore, copper wires have outstanding advantages in the use of solar power stations, especially in the field of directly buried cable power supply. It can reduce the accident rate, improve the reliability of power supply, and is convenient for construction, operation and maintenance. This is the reason why copper wires are mainly used in underground power supply in China.
Solid or Stranded: The cable could be solid or stranded, where stranded wires comprise of numerous small wires that allow the wire to be flexible. This type is suggested for larger sizes. The current tends to flow on the outside of the wire, thus stranded wires have slightly better conductivity as there is more wire surface.
Insulation: The insulation covering wire can protect the cable from heat, moisture, ultraviolet light or chemicals.
Color: Electrical wire insulation is color-coded to designate its function and use. For troubleshooting and repair, understanding the coding is essential. The wiring label differs according to AC or DC current.