Although wiring is one of the least expensive components of a small solar electric system it is not the least important. Even for a small system, mistakes in wiring can have serious consequences. These are easy errors to make. There are hundreds of types of wires and paraphernalia available for different purposes. So
The components of a solar electric system, including wiring are interconnected and dependent. The charge controller must be large enough to manage the solar panel’s energy. Therefore, the wiring must also be large enough to transport the current or energy from one another. This applies to all cables and wiring between components.
Both “wire” and “cable” can be used to refer to wiring. To clarify, the difference is that wire is thinner/thinner, and cable is larger/fatter. Although it is generally true, it sounds a bit technical. The technical explanation is that wire is one conductor wire, while cable is a collection of conductors wrapped in insulation within an even larger insulator.
A cable/wire that connects two components can catch fire if it is too short (or too big) or too long. So, size matters, a lot. It is better to have wiring that is too large than too small. It is tempting to choose smaller wiring to save money. Do not do this. The cost of a wire or cable depends on its size and type. It can cost anywhere from $4.50 per 25 feet up to $70.00 for 5 feet.
Wiring size and amps
The gauge of wire or cable is used to measure its size. Also known as AWG. AWG is used as an identifier. AWG stands for American Wire Gauge. This is a standard wire gauge measurement system that has been used in the U.S. since 1857. It measures the diameter of the conductor wire.
For example, you could see 12 “gauge” or 12 “AWG”, which both mean the same thing. Increasing gauge numbers, bigger gauge numbers, indicate decreasing, smaller, wire diameters. A 22-gauge wire is much smaller than a 16-gauge wire, and it’s a lot smaller that a heavy 8-gauge or 8 AWG wire. For most people, this is counterintuitive as larger usually refers to bigger and not smaller. You can also spell “Gauge” with “gage”.
The amps rating is the maximum current that can pass through the wire. The gauge is determined by the current (amps) and how thick the wire is. Consider, for instance, that your solar panels (assuming you have two) produce 5 amps total and 2.5 amps each. Assuming the controller is nearby, let’s say the distance between the panels and the batteries/controller is 20 feet.
You’d need a 13 gauge wire. To account for my “feet”, I would use a 13 gauge wire.
The Wiring Size and Distance
It matters. The size of the wiring is not determined solely by amps. You also need to consider the distance between components. An increase in distance means that the wiring is heavier.
This is called OHMS. The OHMS law states that current increases when voltage drops, as it does over distance. The increase in voltage must be accommodated by the wiring. A wiring chart might indicate that 5 AWG wire is required for 5 amps above 10 feet, 15 feet, and 40 feet respectively.
Another perspective is that if you have a 10amp usage device, and the wire can’t handle an increased current distance, it will be impossible for the wire to handle this. In this situation, it would be smarter to increase the wire size. You cannot exceed an amp rating.
The multi-stranded wire is used for 12-volt DC circuits. It is also known as “stranded”. Instead of one piece of wire like the ones you find in your home, stranded wire is broken into smaller strands.
These strands are then encapsulated with an insulating substance. Stranded wire is often used in areas that are subject to vibration, such as boats, RVs, and airplanes. A single strand of wire can be damaged or weakened under the same conditions. It is easier to work with stranded wire.
Big Easy Wiring Mistake- Mixing Negative and Positive Wire
Except for components and DC devices that plug into a receptacle such as the power cord in your car, 12-volt systems come with both positive and negative connectors. They can’t be mixed together! You can’t mix them up!
The negative wire from the inverter is connected to the battery’s negative post, while the negative wire from the solar panel connects with the charge controller’s negative connection, which connects directly to the battery’s negative post. The same goes for the positive wires, except that they are connected to the positive connectors. Solar panels, charge controllers, inverters, etc. Not all solar panels come with wiring instructions. If you have them, be sure to follow them.
Here are some common solar wiring connectors for small systems
Ring terminals
Ends are what connect wires to other things. Wires do not come with ends. The ring terminal, also known as an insulated ring terminus, is a common “end”. A ring terminal is small, metal ring that’s crimped onto wires and then covered with electrical tape or another protective insulator.
The ring terminal can be attached to the secondary posts of your batteries. This ring terminal can be used to join two wires that you may want to separate later. You could also use a bolt and nut. They also come in different sizes. All items must be compatible and strong enough to withstand the electric current, including the ring terminal.
Terminals forks
A fork terminal, which is similar to the one above but in a U-shaped shape, is a terminal that can be used for transferring money.
Butt splices
Sometimes, a wire is too short. A butt splice is a way to connect two wires together. This connector allows you to connect two wires together. This connector can also be used to gauge wires.
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