Choosing Stranded vs. Solid Wire Cable

June 13, 2022 / General, 101 learning, Installation and testing, Best Practices

You’re probably aware that both shielded and unshielded twisted-pair copper cable comes in either stranded or solid wire versions. There are plenty of considerations when it comes to choosing one or the other, including standards, environment, application, and cost. Let’s take a look at the differences and considerations, so you can decide which cable type is right for your specific installation.

The Differences Between Stranded and Solid Wire Cable

The first difference between stranded and solid wire cable is in the way they’re made: the terms stranded and solid refer to the actual construction of the copper conductors within the cable.

• • In a stranded cable, each of the eight copper conductors are made up of multiple “strands” of small-gauge wires that are wound together concentrically in a helix, much like a rope. Stranded wire is typically specified as two numbers, with the first number representing the quantity of strands and the second representing the gauge. For example, a 7X32 (sometimes written as 7/32) indicates that there are 7 strands of 32 AWG wire that make up the conductor.


• • In a solid cable, each of the eight conductors are made up of a single larger-gauge wire. Solid wire is specified by just one gauge number to indicate the size of the conductor, such as 24 AWG. Whether it’s a one-, two-, or four-pair cable, the gauge of the solid conductor is the specification for the cable.

This leads to the most noticeable difference: flexibility. Stranded cables are much more flexible and can withstand more bending; in terminations, however, those flexible strands can break or become loose over time. Solid cables are more rigid and can break if flexed too far or too frequently, but solid conductors will hold their shape over time and seat properly within insulation displacement connectors (IDCs) on jacks, patch panels, and connecting blocks.

A less-obvious difference between stranded and solid wire cable is performance. In general, solid cables are better electrical conductors and provide superior, stable electrical characteristics over a wider range of frequencies. They’re also considered more rugged and less likely to be affected by vibration or susceptible to corrosion, since they have less surface area than stranded conductors.

Solid wire can also carry more current than stranded wire. Higher-gauge (thinner) conductors have more insertion loss than lower-gauge (thicker) conductors; stranded cables exhibit 20 to 50 percent more attenuation than solid copper conductors (20 percent for 24 AWG and 50 percent for 26 AWG). Because the cross section of a stranded conductor is not all copper (there’s some air in there), they also have higher DC resistance than solid cables.

Now that you understand the differences between stranded and solid cable, let’s cover what you need to consider when making a choice.

Is Stranded or Solid Wire Better?

When it comes to 90-meter horizontal permanent links, there’s no choice: whether it's shielded or unshielded twisted pair, both TIA and ISO/IEC standards require solid cable. Stranded cable (24 and 26 AWG) is limited to patch cords and 10-meter lengths within a 100-meter channel.

Because stranded cables are more flexible and can withstand bending, they make excellent patch cords for equipment connections and cross-connects where cables are frequently bent and manipulated; at just 10 meters of the channel, the increased insertion loss and resistance aren’t a factor in the overall channel performance. However, smaller 28 AWG stranded patch cords that have even more insertion loss and resistance due to their smaller gauge do have some limitations — get the Skinny on 28 AWG Patch Cords to learn more.

Open office environments, however, are special situations; they’re faced with regular reconfigurations and may require a more flexible cabling system. In those installations, the standards allow stranded patch cords to take up more than 10 meters of the channel. However, if you’re using more than 10 meters of stranded cable in a channel, industry standards require de-rating the overall channel length to accommodate for the greater insertion loss and DC resistance.

When it comes to de-rating stranded cable per industry standards, the overall gauge is a factor: higher-gauge (thinner) cables have a higher de-rating factor. The de-rating for 26 AWG stranded cable is 0.5, while 24 AWG is only 0.2, and 22 AWG stranded cables require no de-rating at all.

Here are the calculations to determine overall channel length, where H=horizontal cable length, D=de-rating factor, C= total stranded cable length and T=total channel length.

 

For example, if you’re using 60 meters of horizontal solid category 6A cable and 40 meters of stranded 24 AWG category 6A patch cable with a 0.2 de-rating factor, the total length of the channel must be reduced to 97.5 meters. (If you prefer the actual math: total stranded cable length = [105-60]/[1 + 0.2], or 37.5, and total channel length = 60+37.5, or 97.5 meters.)  If you’re using 26 AWG stranded cable with a 0.5 de-rating, the channel length needs to be reduced to 90 meters.

PoE Makes Greater Demands on Stranded Cable Patch Cords

While stranded cable is the norm for patch cords at patching areas in the telecommunications room (TR) and at the work area (perhaps longer than 10 meters in open offices), a primary application to consider in today’s LANs warrants the use of solid patch cords: Power over Ethernet (PoE). When PoE is delivered over twisted-pair copper cable, some of the power dissipates as heat. When power dissipates as heat, the cable temperature increases. With higher insertion loss and DC resistance, stranded patch cords are more likely to exhibit degraded transmission performance at elevated temperatures.

While not typically a concern in environmentally controlled spaces like the TR, stranded patch cords could become an issue once you start connecting devices in the ceiling — think wireless access points, security cameras, LED lights, and more. In best practice, if the environment isn’t temperature controlled and the cable doesn’t have to bend much, solid cable patch cords should be used. If you do use stranded patch cords in uncontrolled environments, it’s better to keep them short (about 5 meters or less). And when it comes to higher-temperature environments, industry standards require de-rating channel length for that, too; more cables in a bundle, each generating more heat, can require even more length de-rating (though there can be An Exception to Every Rule).

Balancing the Cost Difference Between Stranded and Solid Wire

While more strands in a conductor mean greater flexibility, a higher strand count also means a higher price. To keep costs down, stranded category 6 and category 6A cable are designed to strike a balance: enough strands to maintain proper flexibility, but not so many that it creates a dramatic price difference. You don’t have to compromise performance (or standards compliance) by selecting stranded wire cable instead of solid for environments and applications for which it’s not suited. Keep your stranded cables in environmentally controlled areas that require greater flexibility, and use solid wire cable where rugged performance (and little bending) is required.

Whether it’s patch cords, permanent links, or channels, you can configure a Fluke Networks Versiv™ tool to certify the cable's performance.

View the Versiv Configurator

Wire harnesses and cable assemblies, among other electrical power distribution equipment use solid and stranded wires. While stranded wire is made up of multiple thinner wires twisted together to form a bundle, solid wires have a solid core. Each has unique advantages, and the best option for a given application depends on the particular needs of the project.

What is stranded wire?

Bundled wires are compressed together, then covered in non-conductive insulation. Because stranded wire is more flexible, it is perfect for bending and twisting to fit complex shapes or connecting electronic components in small areas. Stranded wire won’t split or sever and is more malleable than solid wire. It is frequently utilized for indoor applications including speaker lines, circuit boards, and electronic devices.

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Stranded wire benefits

• More flexible
• In motion applications, stranded wire has a longer flex life and is easily routed and bent.
• Less heating and safe current flow
• Ideal for patch cable connections and crimp termination
• Less skin effect (current flowing on the outer surface of the conductor instead of the whole conductor) when in longer power transmission at a higher voltage.

Each of the conductors in a stranded cable is constructed from a number of small-gauge wire “strands” that are concentrically twisted into a rope-like helix. Two numbers are commonly used to specify stranded wire, with the first number indicating the number of strands and the second indicating the gauge. For instance, a 7X32 (also known as 7/32) designates that the conductor is made up of 7 strands of 32 AWG wire.

Stranded Wire disadvantages

• increased risk of corrosion, particularly in outdoor applications
• a lower current capacity than a solid conductor of the same size.
• increased voltage loss
• noisy sound with 20–50% attenuation and medium high-frequency transmission performance
• complex connection and termination
• comparatively expensive versus solid wire

What is solid wire?

In comparison to stranded wire, solid metal core wire, usually referred to as busbars, is a significantly heavier, thicker product. It is ideal for outdoor application where larger currents and more durability are needed. This sturdy, affordable wire can withstand inclement weather and harsh environmental conditions. Various outdoor uses, vehicle controls, and building structures frequently employ it to transport strong currents.

Benefits of Solid Wire

• perfect connection and termination
• high ampacity compared to stranded wire of the same size
• clear sound (reduced noise due to low attenuation) and effective high-frequency transmission
• anti-corrosive and less resistant in indoor and outdoor applications
• ideal for long-distance applications and low voltage drop
• less expensive than stranded wires

The conductor in a solid cable is constructed from a single larger-gauge wire. Solid wire is identified by a single gauge number, such as 24 AWG, to represent the conductor size. The cable’s specification is determined by the gauge of the solid conductor, regardless of whether it has one, two, or four pairs.

Problems with Solid Wire

• Less adaptable
• If utilized in repetitive motion applications, it can harm the cable.
• Skin effects from high-voltage and electricity transmission lines might cause problems.
• Not subject to litigation in electronic, digital, and computer applications

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Solid vs. Stranded Wires: The Major Distinctions

Examining the benefits and drawbacks of the two distinctly different types of wire is necessary when comparing stranded and solid wire. The options are reduced through comparison based on how the unique qualities of the wires relate to their anticipated use and the project requirements. You must first decide which weather resistance, elasticity, and resistance to splitting or severing standards apply to your application. then decide which wire best satisfies those requirements.

Among the main distinctions between solid and stranded copper wire are:

Current capacity of stranded versus solid wire

Greater thickness of solid wire results in less surface area for dissipation. In stranded wire, the thinner wires have air gaps and larger surface area due to the individual strands, which results in more dissipation. The solid wire gives a larger current capacity when deciding between solid and stranded wire for electrical applications.

The solid wire will carry more current than the stranded wire if the diameter of both wires is the same. This is due to the air gap that exists between the conductor strands of stranded wire. To achieve the same current capacity, the cross sectional area of a stranded wire would need to be larger than that of solid wire. Because of this, an electrician must choose the right wire size based on the wire gauge and ampacity needed for the intended application.

Another occurrence in AC current with frequency is the skin effect, when current flows on the conductor’s outer surface rather than the entire conductor. For high power transmission stranded wires are used. However, in the case of copper wire (up to 6mm) used for household wiring with a frequency of 50/60 Hz, skin depth may be disregarded.

Routing

Stranded wires are more flexible and bendable than solid wires, making it simpler to route them around obstructions.

Flexibility

The most obvious difference that results from this is flexibility. Stranded cables are far more bendable and flexible, however over time, the flexible strands in terminations may break or come away. Solid conductors will keep their shape over time and properly fit into insulation displacement connectors (IDCs) on jacks, patch panels, and connecting blocks. Solid cables are more stiff and can break if bent too much or too frequently.

Wires with strands are more flexible and can withstand greater flexing and vibration without breaking. In situations where there is a lot of movement or vibration, solid wires might need to be replaced more frequently than stranded wires.

Cost

Solid wire is more cost-effective than stranded wire since its production costs are so much lower. This is most likely due to the ease of production. Solid wire is significantly easier to create because it is single-core in nature. To twist the thinner wires together form stranded wires, more difficult production procedures are needed.

Distance

Solid wires are a preferable option for longer distances since they have less current dissipation. Shorter distances will see good performance from stranded wire.

Performance

Solid cables have superior, stable electrical qualities over a larger range of frequencies and are, in general, better electrical conductors. Since they have less surface area than stranded conductors, they are also thought to be more robust, less likely to be impacted by vibration, and less likely to be subject to corrosion.

Also, solid wire has a higher current capacity than stranded wire. Stranded cables display 20 to 50 percent more attenuation than solid copper conductors, while higher-gauge (thinner) conductors have more insertion loss than lower-gauge (thicker) conductors (20 percent for 24 AWG and 50 percent for 26 AWG). Stranded conductors have higher DC resistance than solid cables because their cross section is not entirely made of copper (there is some air in there as well).

Stranded wires do not always outperform solid wires. According to the application. Better for fixed installations are solid wires. For uses where the wire must bend, stranded wires are preferable.

Are stranded or solid wire better power cables?

A wire and cable type must be chosen based on initial and ongoing costs, indoor/outdoor and specialized applications, load kinds, motion, the appropriate ampacity, and other weather and environmental parameters, among other considerations. As a result, deciding between solid wire and stranded wire depends on a variety of criteria.

Simply put: Solid wire is the option for you if you desire longevity, simplicity, smoothness, and, most importantly, a cost-effective solution depending on your required applications.

Stranded wire is your best option if you need long-term flexibility and specific motion-based applications.

The line current in the conductors will be significant for transmission and distribution lines that need to have a high power capacity, which is why large diameters are required. The conductor’s size will determine how much current flows through it.

The capacity of the line can be significantly increased by pushing the temperature up but, at that higher temperature, the conductors will sag much more. The maximum capacity of the line will be constrained by the sag of the conductors if the structures are not made to withstand larger sag, which is why various core types are employed. For example carbon fiber cores expand less than steel and are lighter, the sag caused by heating of the cables is reduced.

According to NEC code, a house’s internal wiring must be secured to the frame of the building. Solid wire is typically utilized for the permanently placed wiring because it does not need to move and is less expensive. Stranded wire is used to make appliance wires that plug into walls so that they may lay flat and move freely.

Solid copper wire easily breaks, especially when it is slightly dinged. The majority of electrical connections require some wire bending and arrangement to fit in the final position, increasing the risk of a fracture. It can take hours to locate and fix the problem, and you are unaware of it during installation.

Does stranded wire have a higher amp capacity than solid wire?

Not at 50 or 60 Hertz, where the majority of power is transferred. While solid wire is easier to bend into attractive places in a panel and easier to terminate because you won’t have a stray strand not under a terminal, stranded wire is easier to draw through lengthy conduit lines.

Solid wire and stranded wire are not distinguished in ampacity (amperage capacity) tables.

Wires are typically assigned a gauge designation that indicates their comparable diameter for both solid and stranded wires. Therefore, generally speaking, a solid wire with the same 14 Ga classification and a 14 Ga stranded wire will carry the same current safely.

Remember that the stranded wire will have a slightly larger physical diameter because the packing of the strands leaves open spaces, and the overall diameter will be greater due to the open interstitial spacing in order to obtain the same resistivity or copper cross section.

What about data cables? Solid vs. stranded

Due of stranded wire’s attenuation, solid wire is the recommended option for long lengths. The current dissipation of solid wire is lower than that of stranded wire. Patch cables employ stranded wire because of its exceptional flexibility.

Final thoughts on solid vs. stranded wire

While there are obvious distinctions between solid and stranded wire, the decision to use one over the other is frequently based on the installers’ preferences.

Since copper gets harder with age and stranded wiring has less pulling strain, many electricians observe that stranded wire is simpler to draw in and out when replacing wiring after a number of years.

Solid wire is typically utilized when an electrical project calls for wiring sized 10 and smaller since it is easy to pull and because terminating smaller strands can be tricky for some people. This reduces the likelihood of mistakes when the wiring is completed. Stranded wire is preferred for sizes 8 and up.

Unless solid wiring is chosen for the electrical installation, stranded wiring is used more frequently. Stranded wire is more likely to be utilized in complicated projects with lots of bends. When flexibility is required, stranded wire is the material of choice.

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