Inspecting End to End: Types of Conductors

Conductors

Bare Copper

The de-facto standard for wire and cable, bare copper, serves as the most common type of conductor used in a grand majority of applications. The stranding of this conductor can range from a singular “solid” conductor to a grouping of finer wires together making a “stranded” conductor. Whether the component is solid or stranded dictates which coating options are available.  

In terms of capacity and capability, this conductor is more stable, durable, conductive, and outperforms its aluminum counterpart. However, these perks do come at a cost, quite literally. Copper conductor is substantially more expensive than aluminum.

Aluminum

The latter of the two most common types of conductors, aluminum excels in applications that are both cost-conscious and low-stress, but otherwise falls short of its copper counterpart. As mentioned earlier, aluminum wire is around 50% cheaper than copper on average, and it is also substantially lighter.

When it comes to the capabilities of the product itself, aluminum has a significantly higher electrical resistivity, however, this comes with the caveat of the component needing over a 50% larger cross-section to carry the same current as copper.  Aluminum wiring is softer than copper, and as such expands and contracts more, meaning it has a tendency to lose contact with connection points in certain situations. This can cause arcing, melting, or even fires, which understandably narrows its use cases and makes it a much more niche product.

Steel / Steel-clad

Steel isn't nearly as common as its aforementioned counterparts, primarily because it doesn't conduct electricity nearly as well. However what steel does provide is exceptional mechanical strength, leading to it being a common option for grounding applications. Even still this could be copper-clad steel, rather than solely steel.

Alloy Conductors

Essentially a catch-all category for the remaining common types of conductors used in electrical applications, alloys are conductor materials made from one or more metallic elements. A synergy is created when these elements are combined, leading to these new alloys being stronger than if their elements were used alone. Alloy conductors are typically plated with either silver or nickel.

Conductor coatings/platings

Tinned

The first of the options for coatings, tinning a conductor involves individually tinned strands, this option serves as the lowest cost of all tinned varieties.

Heavily Tinned

Similar to tinning, and as the name implies, this option still tins the individual strands but does so with a higher thickness of tin applied. This type of tinning retains the base flexibility of the product for the majority of its length, as only the end(s) are affected.

Overcoated

This option involves applying an overall coating of tin to the length of the stranded tinned wire. While it presents as a solid conductor it still maintains some level of the stranded materials flexibility and is not prone to breakage under continual flexing like a solid conductor would.

Topcoated

Similar to overcoating, this option is available for bare copper products. It boasts the same benefits as the previous entry.

Prefused

As known as “prebonded”, this option is constructed with strands of heavily tinned copper that are fused via heat along the length of the product. Similar to the last two entries, this option presents characteristics and ease of use that align with a solid conductor but would not work-harden or break under conditions in which a solid conductor would.

Silver plating

Even though silver is the most conductive metal, due to its cost, it is rarely ever used as the conductor for a product unless there is no substitute. However, silver plating is widely utilized in order to widen the operating temperature range without negatively affecting conductivity due to the cross-section contact area.   

Nickel plating

Similar to silver, nickel boasts a much larger operating temperature range than solely copper products (or any of the other listed options above for that matter). In addition to this, it also carries a higher corrosion resistance as well as mechanical toughness, making it quite the desirable plating option for products that need to be able to take on the harshest conditions.

Coating Methods

Hot Dip

For this option, the conductor is run through a molten bath of the coating material. While this does apply a coating of material across the desired length, there may be slight fluctuations in the thickness of the applied material.

Electroplating

This option utilizes the electrolysis method to ensure that a uniform amount of coating material is applied and bonded to the base conductor.

Cladding

The last and most brute force method of bonding, this method uses heat and pressure to weld two or more dissimilar metals together.