Solid Vs. Stranded Copper Wire

By Brenda Priddy

Solid and stranded copper wires have been among the most important wire types used for electronics. Each type of wire has its own strengths and weaknesses. Many different electronics have a need for both types of wiring while other projects require one specific type of wire to be used. When choosing the type of wire that is used in a project, engineers need to assess the stresses that will be placed on the wiring during the operation of the piece of equipment in question.

Flexibility

In many cases, the type of wire that is used in a piece of equipment revolves around the need for flexibility. In equipment that has a great range of motion that will be required of the wire, such as in robots or other equipment with hinged areas, a great deal of flexibility will be required of the wire. When flexibility is needed, it will ne necessary to use stranded copper wire. Stranded copper wire is much more flexible than solid wire and has a much larger range of motion. Solid copper wire can only be used in situations where there will be no movement required.

Impedance

The frequency of the current that is traveling through the wire can determine the type of wire that should be used. As currents travel through the wires, currents that travel along the outer layer tend to be lost into the air; this effect can often make solid wire a more appealing solution due to the decreased surface area. Stranded wire often loses current due to the increased surface area of each individual strand and the air gaps that are found in between the wires. However, several stranded wires are designed for higher frequencies and insulate each individual wire in the bundle. These wires are one of the best solutions for reducing impedance.

Uses

In general, stranded wire should be used in situations where a great deal of flexibility is needed and solid wire should be used when rigidity and strength is necessary. Stranded wire is typically used in circuit board connections, audio headphones and connection areas around moving joints. Solid copper wire is used in electric motors, coils and magnet wiring.

Costs

Solid wiring is one of the cheaper wiring types to produce and is used in most situations that do not call for stranded wiring. Stranded wiring is one of the more expensive wiring types and, the higher the wire count, the more expensive the wire is to manufacture.

Weaknesses

Solid wire is more resistant to weathering and atmospheric exposures due to its decreased surface area. Solid wire is more resistant to corrosion and other adverse weathering effects. Stranded wire is more suited to uses in a controlled atmosphere and is very susceptible to corrosion.