What Solar DC Cable Sizes To Use For Your Solar PV System?
The solar energy demand is increasing. For those interested in installing solar for their home or businesses, it is important to know some of the important information about solar systems. And one among those is the size of solar DC cables. Considering the right size of cables has an extensive impact such as the safety, performance, and overall cost of the system. In addition, it is also important to ensure that those cables fall within the relevant standards.
Let this blog help you to know the sizing of solar DC cables to be used for your solar system.
Solar DC Cable Size
Solar DC cables are extensively used in solar power systems. These cables are exclusively designed to conduct DC current produced by solar panels to the solar inverter. Typically, if the inverter is considered the heart of a solar system, then the DC cable system is at its core.
Thus choosing the right solar DC cable size is crucial for the utmost performance and safety of the system. If the solar cable is sized more or less than the required, the current flow will meet higher resistance than expected and it impacts the power moving to the battery or the grid. If a thin-diameter cable is used, it can end up heating the wire and even can lead to fire or other disastrous effects.
Each solar cable is designed to manage a specific amount of voltage or amperage. Different sizes of solar cables are required to connect the panels to the inverter, batteries, or the inverter to the grid. In addition, DC cables differ majorly from solar AC cables. Since solar DC cables are intended to have high flexibility, current-transforming capabilities, and thermal performance, the major material used in such cables is copper. Moreover, DC cables can perform power evacuation which is a different phenomenon compared to AC cables. Hence focusing on the right solar DC cable sizing becomes important in solar PV systems.
Calculating Solar DC Cable Sizing For A Solar System
The size of the solar DC cable required for a solar PV system will be based on the type of solar system you use. The most popular DC cable sizes are 4 mm, 6 mm, and 10 mm cables.
Choosing the optimal solar cable size is determined based on the following factors, assuming the standard operating conditions.
- Voltage drop
- Cable length
- Current rating
- Voltage and wire sizes
1. Voltage Drop
The voltage drop parameter helps in understanding how much an undersized cable aids in reducing the voltage. Voltage drop varies from system to system, whereas 2.0% is the common criterion. Voltage drop can be figured out using the below formula.
Information such as the length of the cable, voltage drop percentage, and whole amperage are required to calculate the voltage drop of a solar system. Minimizing the voltage drop is an essential factor when it comes to making a system work at its peak efficiency.
Amperage x Feet / Voltage Drop percentage
The longer the cable size you use the more voltage will be lost. By estimating the voltage drop, you can calculate the right DC cable size. Calculators for voltage drop will be useful to find the value. It is a good practice to keep the voltage loss under 3%.
2. Cable length
Though it appears to be simple to calculate the length of the cable length, it is important that you consider the true length of the cable. Calculate the minimum cable length to avoid any losses. With values such as voltage (V), the current (A), and the total length of cable required, along with the maximum permissible percentage voltage loss (%V), you can estimate cable length.
3. Current ratings
Generally, solar DC cable manufacturers present with the product certain tables of current ratings that will be applicable to the size and type of the cables. It is recommended to check this rating before using it. Undersized cables can result in considerable power loss. Remember, amperage ratings will differ, and based on that you can choose the DC cable size.
4. Voltage and wire sizes
Systems with larger inverters can lead to larger DC currents. In case of increased system voltage, there will be a drop in the DC current. Accordingly, the cables can be thinner.
To put it simply,
Increase in voltage – cable will be thinner
Importance Of Choosing The Right Solar DC Cable Size
It is vital to have the right solar DC cable size for assured safety and to yield the maximum performance of the solar PV system. You can use a thumb rule of cables up to 5 meters and can reach up to the nearest available size of DC cables.
Current / 3 = cable size (mm2)
Unless the cable size can’t fulfill the required demands, it increases the risk of overheating, and even fire in some cases. It doesn’t matter the size of the solar system, the cable size holds its crucial importance. It is suggested to larger or longer cables, however, never go for smaller cable sizes.
Below are also the considerations in determining the cable size.
- Solar panel rating
- Distance between the panels and loads
With higher the solar panel capacity (in watts), the thicker the size of the solar DC cables will be. A general rule for using cables is to have a cross-sectional area of 2.5mm²/1000W of solar panels.
The bottom line is when it comes to the question of which solar DC cable sizes to use for a solar system, the answer lies in having clarity on the expected year-long variations with the PV system. It is highly recommended to consult with a certified electrician to ensure the right solar cable sizes for your solar power system before you connect with any wires.
Improve The Performance Of Your Solar Installation With The Best Dc Cables
The APAR solar DC cables at Powernsun meet the highest standard requirements for your solar PV system. These solar cables are designed to fulfill the expectations of higher weather resistance and longevity. We strongly recommend using our high-quality APAR Solar DC cables and APAR armoured cables. These cables are double-insulated for the best safety and are tested for thermal endurance, ozone resistance, smoke emission, dynamic penetration, and UV resistance against applicable standards.
Hope this blog helps you in recognizing the importance of choosing the right-sized solar DC cables. If you are intended to buy solar DC cables that provide maximum efficiency and better energy transmission, Powernsun is your best place.
