Solar cables and wiring: sizing and AWG explained

This article discusses the different types of solar cables and solar wiring.  Also it describes the American standard for solar cables, which is the AWG (American Wire Gauge).

Transportation of electrical energy

Cables and wires are considered as veins and arteries of any electrical power system.In most cases, electricity is generated at one place and is consumed at another. This transportation of electrical energy is facilitated by employing a proper network of cables, wires and buses.Solar energy systems are no different. Electrical energy may be generated by a solar panel, mounted on the roof, and may be required to power loads in the basement.This transportation of electricity is made possible by using solar cables and wires.While cables and wires are generally used to represent the term ‘wiring’, there is a major difference between the two.A Solar Wire is referred to as a single conductor, smaller in diameter, while cable is a group of conductors within an insulation jacket.A cable may contain any number of conductors and varies in its external diameter.

Correctly sizing the solar cables and wires in a solar system

It is extremely important to use the correct solar cable size when connecting various components of a solar energy system.Properly sizing the cables ensures that there is practically no overheating and very little loss of energy. Using an undersized cable not only poses a potential for causing fire due to overheating, but is also a code violation in most jurisdictions.In a typical solar power system, wiring is needed to connect these four components together:
  1. The solar panel (used to generate electricity)
  2. The inverter (used to convert DC electricity to AC, as most of our home appliances need AC input)
And for Off-Grid systems:
  1. The charge controller (used to prevent the batteries from over charging)
  2. The batteries (used to store electrical energy for later use)

Factors determining the solar wire size

The size of the wire to be used depends upon:
  1. The generating capacity of the Solar Panel (larger the current generated, bigger the size)
  2. The distance of the Solar Panel to the loads (greater the distance, bigger the size)

AWG (American Wire Gauge)

The size of the wire is measured in AWG (American Wire Gauge) and is a standardized wire gauge measuring system.As a rule of thumb, the bigger the AWG number, smaller is the wire.A 16 AWG wire is smaller than a 12 AWG wire, which is way smaller than a 4 AWG wire.A large number of tools are present on the internet which helps in selecting a properly sized cable for your solar panel installation.


on 19 Feb 2019

i also would like to know is there is any formula to carculate wires size

Kayode Onigbinde

Kayode Onigbinde

on 15 Feb 2017

Hi, Thanks for the information. Please is there any standard formula to calculate the wire size? I use 12amp=10mm, there I do proportion for a larger amps. Pls if there is any formula, pls send it to me and take note of mine should I Continue. Thanks



on 09 Nov 2022

I see long runs of "solar wire" connecting panels to MPPT chargers typically at 10awg this would be way to small for even modest loads of 30A if the runs are 20+ feet correct?

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