June 15, 2012 AT 11:10 am

ASK AN EDUCATOR! – “What is the functional difference between stranded and solid-core wire?”

Nicky asks:

What is the functional difference between stranded and solid-core wire?

Great question!

Solid wire consists of a single strand or core of wire that is insulated with non-conductive material. Typically you will find solid core wire in situations where the wire is not designed to be continuously flexed (i.e. your house electrical wiring, wires for breadboards, etc.)

Stranded wire consists of a bundle of small gauge wires compressed and insulated with non-conductive material. Typically you will find stranded wires in situations where the wire needs to be routed through tight spaces or experiences frequent flexing/vibration (i.e. headphone cables, speaker wire, automotive wire, appliance cables, etc.)

Some advantages of solid core wire:

  • Cheaper to produce
  • More compact diameter for the same current carrying capability as stranded
  • Less likely to fail due to corrosion

Disadvantages of solid core wire:

  • Typically only available in small gauges
  • Continuous flexing or vibration will cause the wire to fatigue and break

Some advantages of stranded wire:

  • Very flexible and withstands a greater amount of flexing and vibration
  • Easier to rout

Disadvantages of stranded wire:

  • Diameter is larger for the same carrying capability as solid
  • More costly to produce as the manufacturing process is more complex
  • More likely to fail due to corrosion from capillary action & a high surface area

I hope this has answered your question and good luck choosing the correct cable!

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“Ask an Educator” questions are answered by Adam Kemp, a high school teacher who has been teaching courses in Energy Systems, Systems Engineering, Robotics and Prototyping since 2005.


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4 Comments

  1. I recall hearing that stranded core wire could cause problems for high frequency signals because the signal may have to travel varying distances down different strands. Bunk? Are there conditions or applications where this would matter?

  2. @Aaron: there may be instances where the flexing of stranded cable can cause varying conductor lengths, thus introducing phase delays (and signal skew or attenuation). However, at frequencies high enough for this to matter, skin effect will be the more prominent cause of problems. At very high frequencies, Litz wire (stranded cable with individually-insulated strands) is more commonly used.

  3. I do know that for carrying data or RF signals, stranded wire can be problematic due to attenuation from the skin effect. For instance, I once worked on a console game mod and had only stranded ribbon cable to use extend a cartridge connection. It caused all kinds of problems until I replaced it with some solid core ribbon cable.

  4. Thanks for answering! I think that this post (and ascociated comments) have answered my question wonderfully. Thanks!

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