Difference Between Solid Cable and Stranded Cable
Difference In Structure
For twisted pair copper cables, "stranded" and "solid" refer to the actual construction of the copper conductors in the cable, and the names themselves clearly distinguish them. In a stranded cable, each of the eight copper wires consists of multiple strands of small gauge wire that will be communicatively wound together in a helix, like a rope. Usually stranded cables are represented by two numbers, the first number indicates the number of strands and the second number indicates the wire gauge. For example, 7X32 (sometimes written 7/32) means a wire composed of 7 strands of 32AWG gauge wire. In a solid cable, each of the eight wires consists of only one larger gauge solid wire, and only a gauge number is used to indicate the size of the wire, such as 24AWG.
For the same category, such as Category 5e, 6, or 6A, it may seem a bit confusing to specify a single size for stranded and solid cables within it. You just need to keep in mind that the final overall size of the wire is the same whether it consists of stranded wires or a single solid wire.
The most significant difference between stranded and solid cables is performance. Since higher gauge number wire has higher insertion loss than lower gauge number wire, stranded wire has 20% to 50% greater attenuation than solid copper wire (20% for 24AWG and 50% for 26AWG) . Also, since the cross-section of the stranded wire is not full copper (there is air in it), its current resistance is also higher than that of the implementation cable. In general, solid wire is a better current conductor and provides excellent, stable electrical characteristics over a wider frequency range. Since they have a smaller surface area than stranded wire, they are also considered stronger and less susceptible to vibration or corrosion.
Another difference is flexibility. Stranded cables are more flexible and can withstand more flexing than rigid solid conductors, which can break if bent too many times. However, when stranded cables are terminated, the individual strands within the conductor can break or loosen over time. Solid conductors, on the other hand, will always maintain their original shape and fit correctly in the IDCs on jacks, patch panels and connection blocks.
Industry Standards and Environment
For a 90-meter horizontal link, there is no other option, as both TIA and ISO/IEC standards require the use of solid-core cables. Stranded cables (24 and 26AWG) are only patch cords, and for a 100-meter channel, only 10-meter long stranded cables can be used. Because stranded cables are more flexible and can withstand bending, they are an excellent choice for device connections and crossover patch cords that require frequent flexing and fiddling, and only 10 meters of access , the increase in insertion loss and resistance does not affect the performance of the entire channel. However, the smaller 28AWG twisted patch cords do have some limitations due to their larger insertion loss and resistance due to their smaller gauge.
Relative to open office environments, there are special cases where the standard allows the use of stranded patch cords in excess of 10 meters within a 100-meter channel, as the standard recognizes that office environments require periodic reconfiguration and may require a more flexible cabling system . However, if more than 10 meters of stranded cable is used in the channel, industry standards require that the overall length of the channel be shortened to accommodate more large insertion loss and DC resistance.
While twisted cable is the standard choice for patch cords in telecom rooms and in work areas, there is an important application to consider in today's local area networks, Power over Ethernet - an application that warrants the use of solid heartbeats. When PoE is transmitted over twisted pair copper wires, some of the energy is dissipated as heat. When energy is dissipated as heat, the temperature inside the cable increases. Because stranded patch cords have higher insertion loss and DC resistance, their transmission performance at high temperatures is more likely to be affected and degraded.
As a result, industry standards call for shorter channel lengths, and the more cables in the bundle, the more heat it generates, requiring input length derating.
The more strands in a wire, the better its flexibility, but the number of strands affects the price, and the more strands that make up the cable, the higher the cost. To keep costs down, Category 6 and Category 6A twisted cables are designed with a sufficient number of twisted wires to maintain proper flexibility, but not enough to make a huge price difference. The added cost of choosing stranded cable in environments and applications where solid cable is not suitable is not enough to make one choose solid cable at the risk of compromising performance or standards compliance. Always use stranded cables in environmentally controlled areas where greater flexibility is required.