Solid wire: Where is it More Suitable Than the Stranded Version?

FACTS CHECKED BY  Jose George​

While creating a wire loop, you must use both solid and stranded wire. By comparing the electrical performance of the same size of wire, you will see that the stranded wire offers more resistance than the solid wire. Thus, solid wire provides a good loop performance.

How to assemble a custom lead wire
How to assemble a custom lead wire

However, stranded wire is more flexible than solid wire, and the loop’s lead-in run requires flexibility. So, you can use stranded wire to make the lead-in part of the loop. Overall, manufacturers prefer solid wire to create the loop part since it is better than stranded wires in many ways. What are the advantages of the type of wire? Let’s find out.

Advantages of solid wire over Stranded wire

  • Solid conducting wires have lesser DC resistance. Moreover, higher frequencies do not have significant effects on them.
  • As you use solid wires, they are less likely to get damaged by the vibrations in outdoor places.
  • Due to its rigid characteristics, the loop of the solid conducting wire stays on the surface of the rebar even when you pour concrete on it.
  • Solid wires hold their shape better. Moreover, their rugged but smaller surface areas make them ideal for dealing with harsh environments.
  • Solid wires work best to support longer ranges of power transmission as they face lesser skin effects.
  • In the end, solid wires are economical, and thus you can get better performance at lesser prices.

Why Stranded conductors exhibit higher attenuation / Insertion Loss than solid conductors?

Let’s look at how do they work to find the reason.

Conductor Diameter

Because of their lower conducting diameter, stranded conductors display more attenuation than solid conductors do. You can define the wire gauge by its overall area, defining the resistance value for a particular conducting material, such as copper.

Due to the resistance, the current-carrying capacity lowers as heat passes along inside the cable. Hence longer cable lengths result in higher heat loss and distortion of the transmission signal. As a result, stranded conductor cables are not suitable for extended cable lengths, and both stranded and solid conductor cables have length restrictions.

Higher Frequencies

The skin effect occurs when conducting materials, such as copper, experience a significant decline in the conducting cross-section at higher frequencies. The skin effect forces the charged particles outward to the metal surface (“skin”) as the frequency of a transmission rises.

As the frequencies grow, the skin depth decreases, and a circular, solid conducting channel hollows out, with electricity passing solely along the outside surface of the cylinder. As a result of the shorter radius of stranded conductors, stranded cables have greater attenuation losses (up to 20% more) than solid-conductor cables.

skin effect 

Caption: skin effect 

Source: http://www.bdloops.com/ 

Conductivity

The skin-effect problem is exacerbated when the outside surfaces of stranded conductors are coated with tin. As the tin has a greater resistance than copper, the current flow does not remain as effective as before since most of the negatively charged particles tend to move towards the tin layer.

Similarly, in untinned conductors, the production of copper oxides creates the same layer as the tin. Moreover, they increase the resistance of the wire, and with it, you will see a massive decline in the performance of the conducting wire. 

Choosing the Right Solid Cable

It is important to consider choosing a solid cable for a certain electrical application.

New Installations and Backbone Cabling

Because inserting any cable type into a building’s structure is costly and better handled by keeping long-term uses in mind, solid conductor cabling’s greater electrical efficiency and longer lengths make it ideal for permanent building connections. Its stability at higher frequencies allows for longer time intervals between cable reinstallations. Its relative weakness is not an issue when shielded from harm by the structure itself.

You can install long cable lines (up to 90 meters, or 290 feet) within walls, under roofs, or through underground pathways joining neighboring buildings. Because most people use a single wire for these persistent cabling purposes, you can also label it as a network cable.

Horizontal Cabling

Manufacturers also use solid-conductor cables for horizontal positions (same-floor runs) connecting telecom rooms and workspaces. In addition to functioning better over longer distances and at higher frequencies, the single, bigger conducting wires of solid cables are significantly easier to terminate than the many thin wires of stranded conductor cables.

Furthermore, the relative rigidity of solid conductor cable works great for use with 110-type punch-down connections present on the backs of wall jacks or 66-type punch-down blocks on plywood boards. In contrast, the softness and suppleness of stranded cables make dealing with punch-down connections or IDCs (Insulation Displacement Connectors) extremely difficult.

IDC D-sub Connectors

Caption: IDC D-sub Connectors

Source: https://en.wikipedia.org/ 

The solid wire in the US for home wiring

In the US, solid wire is the preferred material for home wiring. It is due to several reasons:

  • Solid wire retails for lesser prices since its production is easier than stranded wire.
  • Its current capacity is better than the stranded wire. 
  • Additionally, the solid wire offers a more compact structure than the stranded wire when you take the same gauge wires (say 6 American Wire Gauge wire or 10 AWG wire). The feature makes it beneficial to use in small electrical boxes where you need multiple wirings. 
  • While attaching the connectors and terminators to the end of the wires, you might handle solid wires much better. It is because there is only one electrical wire to deal with. In the case of stranded wires, several strands are poking out from the terminator, causing the process to be faulty.
  • When installing and fixing the wires permanently around the corners, using solid wire will not compromise the quality.
  • Solid cores are easier to splice out and will not get any wear/tear as you pull them back. But in stranded wires, the individual strands may get damaged.
  • The skin depth of copper wire at 60hz power frequency is 8.5mm (1/3″), so in the case of home wiring, the skin effect of solid wire can be ignored. It will not play a role if the diameter of the wire exceeds 17 mm (2/3″). In short, you can use up to 6mm (10AWG) of stranded wire to get enough flexibility if needed, not solid wire, which is perfect.
  • Moreover, the solid wires are less prone to corrosion and abrasions due to movement than the stranded wires. These advantages make the solid wire more suitable for outdoor applications. 

Conclusion

There is always a battle between when to choose a solid core wire and when to go for a stranded one. Of course, you are supposed to choose one according to the electrical connections. However, when choosing longer transmission loops, it is always best to go for solid cables. It offers good performance due to its small, rough surface area without any additional cost. Here at Bloom, we offer wiring harnesses and cable assemblies to make your connection with attention to detail.

Get a free Cable Assembly Quote.