Cables are essential to our electricity process, and whether you are upgrading the electrical circuits in your house or you are installing a new solar system, you will need to choose the right cables for your system. However, there are a lot of factors that go into determining exactly how big of a cable you need, and this is actually something you don’t have to worry about. In this article, we will take you through the importance of cable specifications and how they are selected.
It is important to choose the right cable so that your circuit system can have enough current passing through it to meet your power needs. But do you know how to choose cable specifications? In the following we will explain how to choose cable specifications.
Determine the current of the circuit: You can determine the current of the circuit according to the input current of the loads connected to the entire circuit you are installing. Generally speaking, the current of the circuit should be the smallest of the loads in order to prevent the damage of electrical appliances that have small input currents due to the high current. The input current of the load will usually be on the label of the load or on the instruction manual of the load.
Determine the length of the circuit: In the case of cables, just knowing the current of the circuit is not enough to determine the optimal size of the cable. You also need to know the length of the cable. There is a limit to the length that different sizes of cables can be connected to in order to prevent fires from breaking in the cables so as to ensure the personal safety of the users.
Once you know these two figures, you can use the cable ampacity table to find out the best size of cable for you.
For example, your cable needs to pass 10Ah to 20Ah of current, and the length of the cable in the circuit should be about 7 feet. Using the cable ampacity table, you know that you need a 12AWG cable.
Know the specification of the battery cable in the circuit: For the specification of the cable, it is available in many sizes including 2AWG, 4AWG, 6AWG, 8AWG, 10AWG, 12AWG etc. When you buy the cable, usually the salesperson will recommend the right cable for you according to your actual situation, and you will be able to observe the label of the cable directly to determine the specification of the cable.
Measure the length of the batter cable in the circuit: we always have a misunderstanding, we generally think that the size of the current that can pass through the cable is only related to the specifications of the cable, in fact, the length of the cable and the current that can be passed through the cable also has a relationship. It can be said that the longer the cable, the smaller the current that can pass through the cable.
Once you understand the above two figures, you can use the cable ampacity table to determine the maximum current that can pass through the cable.
If you have a 14AWG cable and the cable is 7 feet to 10 feet long in the circuit, then the current that can pass through the circuit is 5Ah to 10Ah.
Voltage Drop: Voltage drop means that the voltage at the output of the battery is higher than the voltage at the load. When the voltage drop is too much, your electronic devices may not work properly. From Ohm’s law Voltage = Current * Resistance. Generally the current in a circuit is to be within a certain range, so the voltage drop is also mainly related to the resistance. However, the length and specification of the cable also affects the resistance. When the cable is longer or the specification of the cable is bigger, the resistance will be bigger and the voltage drop will be faster, which may cause the electronic equipment can not work.
Cable heating: The effect of cable heating on electronic equipment is actually very similar to the principle of voltage drop. When the battery cable specification is relatively small, the cable is more likely to heat up, which will lead to an increase in the resistance of the battery cable, and finally lead to electronic equipment cannot work, and in serious cases, there may be a fire.
Cost: Generally speaking, the larger the gauge of the cable or the longer the length of the battery cable, the more metal material is needed, which results in your cost needing to be higher as well. This is the main reason for the increase in the cost of the cable, so you must choose the cable specification and length wisely in order to reduce your burden.
Aesthetics: The larger the gauge of the battery cable means the thicker the cable will be. Whether you install the cables in your house or in your RV, there will be visible marks on the walls, resulting in a decrease in the aesthetics of your house or RV.
Current and length are two very important factors for choosing cables. The current of the cable is actually the smallest current in the solar system components. You should try to minimize the distance between the components when installing the solar system, because the shorter the cable length, the better, not only to reduce the cost of the cable, but also to reduce the probability of safety accidents. After this, you can quickly choose the most suitable cable for your solar system.
Remember that the selection of the right cable depends mainly on the current and length. And the current and length of the cable will have a great influence on the rest as well. If you choose the right cables, you will not only reduce your costs, but also make your house or caravan more beautiful.
