Cable Thickness

The cable thickness in a photovoltaic system, more specifically the cable cross-section, is a crucial factor for the efficient energy transfer from the solar modules to the inverter and further into the power grid. It determines how much electrical energy a cable can transmit without excessive heating and power losses.

Why is cable thickness so important?

  • Power losses: A cable cross-section that is too small leads to higher electrical resistance and thus to higher losses during energy transmission. This means that not all of the generated solar power will reach the household in the end.
  • Voltage drop: A cross-section that is too small can lead to a significant voltage drop, especially over long distances. This can impair the performance of the photovoltaic system and reduce the lifespan of the components.
  • Overheating: If overloaded, a cable that is too thin can overheat and, in the worst-case scenario, cause a fire.

What factors influence the choice of cable thickness?

  • Cable length: The longer the distance between the solar modules and the inverter, the larger the required cable cross-section.
  • Power demand: The power of the photovoltaic system determines the required current. The higher the power, the larger the required cross-section.
  • Voltage level: The voltage level at which the system operates also influences the choice of cable cross-section.
  • Ambient temperature: At high temperatures, the electrical resistance of conductors increases, so a slightly larger cross-section is recommended for high ambient temperatures.

What are the common cable thicknesses?

For photovoltaic systems, cables with the following cross-sections are commonly used:

  • 2.5 mm²: For smaller systems with short distances.
  • 4 mm²: Commonly used for medium-sized systems and as a standard cross-section in many installations.
  • 6 mm²: For larger systems or longer distances.
  • 10 mm² and above: For very large systems or specific requirements.

How is the correct cable thickness calculated?

The exact calculation of the required cable thickness depends on various factors and should be performed by a professional. There are specialized software programs and online calculators that can assist with the dimensioning.

Summary

Choosing the right cable thickness is essential for the efficient and safe operation of a photovoltaic system. A cross-section that is too small results in power losses and can affect the lifespan of the system. A cross-section that is too large is not problematic but unnecessarily increases the costs.

Relevant keywords: Photovoltaics, Solar system