How to Size the Cable for a Solar System?

Having a solar system means that you should be able to know how to size a cable. We all can agree that a solar system which does not have cable could be easily compared to a highly efficient machine that takes up space and is of no use. The cables are a critical part of the solar systems as they are used for the deployment of electrical energy which is converted from the sun by the controller and is processed to provide energy.

The size of the cable determines whether the solar system runs efficiently or becomes a security hazard.

Calculate the Right Cable Diameter/ Thickness/ Size for the Solar System

Let’s assume that the solar system would power an LED bulb street light. For example the street light is just 36 ft (11m) away from the controller, it would mean that the longest cable running to and from the controller would need to be 72.3 ft (22m) or twice the height of the street light in simple words.

However, for accurate results, the formula below will be useful.

CT = (V ÷ 20) ÷ (Lx I x 0.04)

Understand the terms in the formula

CT = Cross-sectional area of the cable in mm²

V = System voltage

L = Cable length in meters

I = Current in amps

For calculating the needed cable thickness, we would use 12 V as an example.

Calculation of the Needed Cable Thickness at 12 V

20.65mm² = (12V ÷ 20) ÷ (22m x 14.08A x 0.04)

At 12 V, the thickness which is needed for the cable would be too great and it would not allow the system to run effectively.

Which Size is Ideal?

Normally, if one is looking for the ideal size of the cable, then it would either be 48 V or 24 V. Cable wires are expensive and thick, but are a critical part of the solar system without which it wouldn’t be possible for the system to work properly.

Tips on Sizing the Cable for a Solar System

If you want to effectively size the cable, then there are certain things which you need to keep in mind. They will help you size the cable as per the required thickness of the solar system.

The formula mentioned above will help you get an idea about the size of the cable. However, the sizing part is something which requires great care. As the cable is expensive, you need to be sure that you have calculated the value correctly. For better assurance, make sure to calculate the value once more and see if it is the same as before.

Once, you are sure that the value is correct; you can set the cable at a proper surface so as to ensure that it is sized properly. You do not want to make a mistake and start all over. There are many equipment tools which can be used to size the cable of a solar system.

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