Choosing the right conductor

A conductor is a type of material that allows the flow of electrical current in one or more directions. A metal wire is a common electrical conductor.

In national and international standards, the conductor type and size are specified. In other cases, the intended use of the cable is the key reason for selecting one type of conductor over another. Whilst the applications are as varied as the custom design cables made to meet them, some examples might include:

  • Data/signal use
  • Dynamic use
  • High temperature use
  • Crimp terminations
  • Soldered terminations

Metals

There is a wide range of metals that can be used as a conductor, however Copper (Cu) is by far the most common due to its relative low cost and availability. Other common options such as aluminium, steel or tinsel wire (mixed strands of copper and cotton) may offer advantages in strength, weight or flex-life. However, they almost always come at the cost of reduced conductivity.

Plated copper, such as Tin Plated Copper (TPC), Silver Plated Copper (SPC) and Nickel Plated Copper (NPC) offer additional features such as elevated temperatures and improved conductivity or solderability. Purer conductors such as Oxygen Free High Conductivity (OFHC) plated copper can improve the signal performance, and are often used for audio frequencies, whilst High Strengh Copper Alloy (HSA) conductors can provide a much improved dynamic performance over standard copper conductors.

A variety of other metals and alloys are often used for their unique conducting properties when exposed to heat. Commonly known as Resistance Wires, they are used in Thermocouple cables where combinations of resistance wires can be used to detect variations in temperature. Some of the most commonly used are Nickel- Chromium (NiCr), Copper-Nickel (CuNi) and Iron (Fe).

Strandings

The simplest form of conductor is a single, solid strand, however although this offers the smallest diameter, the purest signal and the largest cross-sectional area, this is also the weakest option and solid conductors are prone to breaking after just a few bending cycles. To improve the durability and flexibility of a conductor it is common to strand multiple wires together, the more wires that are stranded together to make a given size, the more flexible the conductor will be.