Apparently, there are some that believe that the “size” or “thickness” of a wire is mostly associated with physical tensile strength, and not as relevant to electrical, current-carrying potential.
This could not be further from the truth.
Not to mince words, though – the thicker the wire, the stronger it will be. That’s a matter of simple physics. However, electrical wire is never used as a load-bearing piece of infrastructure.
Instead, it is used to carry power or signals around a circuit, for any of infinite electrical applications, ranging from powering generators and motors to transferring electrical power from solar arrays and communicating information between the nodes on a communication or alarm system.
Wire gauge is important, but not because of tensile strength.
Wires are commonly rated according to AWG, or American Wire Gauge, which is a logarithmic scale that is inversely proportional to the rating. That is to say, the smaller the number, the thicker the wire, and the higher the number, the thinner with wire.
Now let’s look at voltage, which is more properly known as “electrical potential” and is the product of current and resistance. Current is how “much” electricity is flowing, and resistance is how much “push back” the conductor offers.
Current is measured in amperes, more commonly known as amps. Resistance is measured in units called ohms, and is affected by a wide range of factors; material, temperature, and the length of the circuit.
Many metals, like copper, gold, silver, and aluminum, have a very low resistivity and therefore are suitable electrical conductors. Electrical current can flow through them relatively easily with minimal loss of potential energy.
Poor conductors, such as iron or plastic, have fairly high resistivity. This means they physically resist the flow of electricity through them. The higher the voltage, the more the electricity wants to move – as a result, poor conductors lose potential energy as heat when subjected to high voltage. In extreme cases, the electrical energy may be lost through arcing or corona discharge.
Another thing to note is that as the length of the circuit increases, resistance compounds itself. Therefore, while a length of electrical wire – say, 18 gauge – might hypothetically be suitable in a given application at a set voltage where the circuit was only 20 feet, if the circuit was much longer – hundreds of feet – a larger, thicker wire might be necessary.
Wires are insulated and air is a terrible electrical conductor. Therefore, when conductors like copper wire are subjected to a voltage, the electrical current wants to flow through them instead of elsewhere, since the conductor offers the path of least resistance.
Using a thicker wire creates a wider “channel” for the current to move through. Think of it sort of like this. You have two plumbing pipes – both under the same line pressure. One pipe is twice the thickness of the other. Therefore, the measurable water pressure in the wider pipe would be lower.
Electrical conductors are similar. The wider the wire, the more area there is for electrical current to flow through, and the less resistance the wire offers.
Conversely, if a wire that is too thin is used, there is a serious risk of overheating. In extreme cases, the overheating can cause electrical fires, too.
So electrical wire gauge matters, in order to allow for the safe and effective transmission of electrical energy while preventing risks associated with overheating.
There are other factors that render electrical wire and cable suitable for a variety of applications as well, along with the type of wire used. In addition to voltage rating and wire sizing, the type of cable, (such as insulated or bare copper ground wire), the chemical composition of the outer sheath, color coding, and other specifications, such as suitability in wet locations or dry locations, also impact a wire’s serviceability.
For a wide range of different electrical cables and wiring including residential wiring, marine battery cable, welding cable, submersible cable, instrumentation and alarm cable, and much more, visit EWCS Wire online at EWCSWire.com or contact them at 800-262-1598.