What gauge wire for 100w solar panel?

Gauge wire plays a very crucial role to determine the overall performance and safety of the solar system. Without a proper wire size, you won’t have adequate voltage. On the other hand, it will also lead to excessive power loss. 

In this article, you will all the details of the solar wire system. Therefore, you can also ensure the system is running smoothly and serving adequate voltage. 

Let’s get straight to the topic. 

What is size gauge wire needed for a 100w solar panel?

For a 100 watt panel, the wire size should be four sq mm. if you can integrate the right size, you will be able to generate up to 20 amps of energy. 

Solar PV Panels can generate Direct Current. Hence, it is required to use Direct current wires to connect the inverter and charger. Hence, it will increase the overall efficiency and voltage capacity of the entire solar system. Even the wires should be UV protected to work outdoor conditions. 

Let us first take a look at the right size of gauge for different solar panels:

No. of solar panelsAmpsCorrect Wire Sizes
1 (100-375 watt)20 amps4 sq mm
3 (100-375 watt)30 amps6 sq. mm
6 (100-375 watt)50 amps10 sq. mm

Keeping no. of panel and watt range in mind, you can choose the ideal wire size. Moreover, if you use an undersized wire, it is likely to result in excessive heat. Eventually, it can lead to fire damages. 

Just like a water hose, an electrical wire also has a certain limitation to carry voltage and power. If you integrate a small wire, then the solar system resulting in supplying less power to the battery grid. 

You will easily get all the sizes in your local hardware store, or you can also order online. 

How do you determine the size of a gauge wire?

For copper wires, there is a specific gauge scale. It is American Wire Gauge. If you use a lower gauge number, it will have lower resistance power. 

Commercially, if you install solar panels of 50 watts, you have to use 10 AWG gauge wires. In addition, with the wiring system, 30 amps of current can flow, even if you are using a single panel. And if you have the capacity to use combined panels, AWG will definitely require a charge controller. 

The integrated charge controller to the battery bank would be the same in comparison to the PV array. If you set the PV array to operate a higher voltage, a 12 to 24-volt battery bank would be adequate for that. In that case, a 1/0 wire size would be fine to run the system


In the table, you will find, the smallest wire is 10 AWG which can be rated at 30 amps. At the same time, it is required only 25 amps. Hence, it will ensure additional safety for wires and the entire PV solar system. 

Hence, determining the cable and wire size, it is important to consider the cable length and impact on losses. Using a long cable, you can reduce the performance of the power system. You can tolerate at least a 4% loss of power. 

To curb this issue, you can opt for high voltage like 24V. It also helps to decrease amps and wire losses. The drill is to design a system using safe wire also be aware of the connection between voltage, losses, lengths, and cost.

Why do you need to have the proper size of gauge wire?

The reason to use a proper gauge wire is to transfer the current to the electrical appliances. Hence, it should have the least metrics of resistance. Hence, with the increasing number of appliances, the wire needs to be updated. 

Using a proper gauge wire is an indispensable fact of using a PV solar panel. Let us find out the reasons:

  • Small wire can be meltdown with a large amount of current. Hence, it depends on the capacity of the cable. With a smaller diameter, you can ensure higher resistance. Therefore, the inadequate size of wire can lead to fire hazards. 
  • Proper size of wire ensures the right flow of electricity. Hence, a lack of power can isolate the ground and lead to current leakage. Eventually, a small amount of leakage can lead to blowing the amp.  
  • Fire damage can disrupt the entire wiring system. On the other hand, you have to comprise high voltage capacity. If the amplifier doesn’t receive proper voltage, its performance would be hampered significantly. 

In case you don’t know, voltage refers to electrical flow and ensures better performance of the electrical devices. 

Where can you buy a gauge wire for a 100w solar panel?

Buying a gauge wire is very convenient nowadays. And if you know the right size, it will be easier to find your perfect match.

For example: if you are looking for a four sq. meter wire, you will definitely get it in local hardware shops. If you prefer shopping online, then there is no better choice than Amazon. You can simply search for four sq. meter wire.

For solar PV installation, I would recommend using Aluminium or copper wire. For both residential and commercial use, copper wires are much better than aluminium. Hence, it is a bit expensive than the other. As copper has better conductivity, most engineers prefer them.

Always go for top brands like LONGi Solar, Trina Solar, Hanwha Q-CELLS, and Sun Tech. Choose the one form ‘Amazon Choice’ range. It will ensure the best deal.

To wrap up

Hope you understand the importance of having the right wire for the solar PV system. Choose the right gauge number from the table given here and ensure better performance and safety as well.

I would especially recommend not to compromise with the quality of the wires over price. The best price ranges from around $40 to $49. However, based on the size of the wire, the price will also change.


I’m Matt, a computer and electronic embedded system developer. Currently, working as an electronic engineer. In my leisure time, I do love to blog about technology stuff. Specially, new advance high tech devices. Portable solar systems are one of topic that I love to investigate. They are becoming more powerful day by day which keep me alert.

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