Common Conductor Materials for Wire and Cable

A conductor is at the center of any wire and is mostly made of metal due to metal's high conductivity. Some metals, however, are more conductive than others. Aluminum, copper, and high-strength alloys are the main materials you'll find at the center of your wire and cable. Each of these metals have different properties and levels of conductiveness so it's important to know how they could affect your next cable or wiring application.

Aluminum

Conductors made from aluminum are lightweight, affordable, and able be used in a diverse range of applications. Although aluminum is less expensive than copper or metal alloys, aluminum is also less conductive.

Copper

Copper conductors can transfer electricity efficiently and are both inexpensive and versatile. Bare copper is most often used, but copper conductors can also be tinned or silver-coated to improve performance.

Steel

Steel is also a common conductor material choice. However, steel isn't as common as aluminum or copper because steel doesn't conduct electricity as well. Common steel conductor applications are utilizing copper-clad steel for grounding conductors or for when an application needs wiring with exceptional mechanical strength.

High-Strength Metal Alloys

High-Strength Alloys are common conductor materials made from one or more metallic elements. They are generally stronger combined than when compared to the elements used alone. High-Strength alloy conductors are generally silver-plated or nickel-plated.

Common Types of Conductor Coatings

Conductors can be coated with other metals to improve electrical performance and other characteristics.

Silver-Plated Conductors

Although silver is the most conductive metal, it is very expensive and is rarely used to construct an entire conductor. A much more common design are silver-plated conductors. Silver-plating enhances conductivity and widens the wire’s operating temperature range. A silver-plated wire can usually perform from temperatures of -65°C to 200°C, making this coating is a common choice for many aerospace applications.

Nickel-Plated Conductors

A coating of nickel can be applied to a conductor to increase corrosion resistance and to expand the operating temperature range of a wire or cable. If the nickel is thick, a wire may be able to withstand temperatures of up to 750°C. Nickel-plating also adds a layer of mechanical toughness for cables that must withstand extreme conditions.

Tinned Conductors

Conductors can be tinned to improve water resistance, increase conductivity, and to allow for easy soldering. Tinned conductors are more expensive than bare metal conductors, but can last up to ten times longer than non-tinned conductors. Generally, tinned conductors are used in electrical and electronic equipment in a wide range of industries. There are different types of tinning designed to meet the various needs of different applications. Common types of tinning are:

• Tinned: With basic tinning, individual strands are coated with tin. This is the least expensive method of tinning. It is accepted under UL, CSA, ASTM, and Mil-Spec standards.
• Heavy Tinned: This is similar to basic tinning, but it uses a much thicker coating of tin. It is commonly used in high-frequency induction heaters because it can bond on stripped areas while the rest of the cable remains flexible.
• Prefused or Pre-bond:In prefused or pre-bond tinning, heavy tinned copper strands are twisted and then fused along their entire length. This type of tinned conductor shares the characteristics of a solid conductor but is less likely to break or work-harden in flex applications. Prefused or pre-bond conductors are usually accepted under UL and CSA guidelines, but not by Mil-W-16878 cable specifications.
• Overcoat: This type of tinning involves covering tinned, twisted copper strands with an overall coating of tin. Its advantages are the same as those of prefused or pre-bond tinning. It is accepted by the UL and the CSA, but not the Mil-Spec standards.
• Topcoat: With topcoat tinning, bare copper strands are twisted together and then given an overall coating of tin. Like overcoat tinning, it is accepted by UL and CSA specifications, but not Mil-Spec.

When designing a difficult or abusive application, consider tinning as an option for your cables' conductors. It may improve the overall function of the cable and increase its longevity.