Almost every electrical system depends on copper somewhere. It carries power through switchgear and distribution boards, through motor and transformer windings, along cables and earthing systems, and into the electronics that control them. Other materials compete in particular niches, but copper remains the default conductor for good reasons.
Why copper is such a good conductor
Copper has the highest electrical conductivity of any common engineering metal. Only silver conducts better, and silver is far too expensive for most uses. High-conductivity copper is the reference material for conductivity measurements: annealed copper is defined as 100% on the International Annealed Copper Standard (IACS) scale, and aluminium comes in at around 61%.
In practice, that means a copper conductor can carry the same current as an aluminium one in a smaller cross-section. Where space is limited, in a switchboard, a battery pack or a compact panel, that matters a great deal.
More than conductivity
Conductivity is only part of the picture. Copper also offers:
- Thermal conductivity. It moves heat away from joints and hot spots efficiently.
- Strength and ductility. It can be bent, punched and formed without cracking, then hold its shape under load.
- Reliable joints. Copper is less prone to creep than aluminium, so bolted connections keep their clamping force better over time.
- A manageable oxide. The oxide that forms on copper is far less of a problem at contact faces than the hard, insulating oxide on aluminium.
- Recyclability. Copper can be recycled repeatedly without losing its properties.
The copper grades used in electrical work
Most electrical copper is one of a small number of high-conductivity grades:
- C101 (Cu-ETP, CW004A). Electrolytic tough pitch copper, the standard choice for busbars, cable and general electrical use. Our guide to electrolytic tough pitch copper explains it in more detail.
- C103 (Cu-OF, CW008A). Oxygen-free copper, used where parts will be brazed or welded, or where the operating environment involves hydrogen.
- Specialist alloys such as tellurium copper or copper-chromium, used where better machinability or higher strength is needed at some cost to conductivity.
For most power distribution work, C101 is the right grade. Whether you need oxygen-free copper is covered in our article on copper grades for busbars.
Where copper is used in electrical systems
Power distribution
Copper busbars distribute power inside switchgear, distribution boards, panel builds and data centres. They carry far more current than cable of a similar size and make tidy, compact connections between equipment.
Windings and machines
Motors, generators and transformers use copper windings because its conductivity keeps losses, and therefore heat, to a minimum.
Cable and wire
Building wiring, control cables and earthing conductors are overwhelmingly copper. Bare copper wire is also used for earthing, bonding and specialist manufacturing.
Renewable energy and electrification
Wind turbines, solar inverters, battery storage and electric vehicles all use substantially more copper than the systems they replace. As electrification grows, so does demand for high-conductivity copper in busbars, connectors and windings.
When aluminium makes sense instead
Aluminium is lighter and cheaper per kilogram, and for some large conductors that outweighs its lower conductivity. Aluminium busbars are a sound choice where weight and cost matter more than space. The decision depends on current, available space, weight limits and how the joints will be made.
UK-produced copper from ILF
ILF Ltd manufactures copper flat bar at our own copper mill in Cannock, Staffordshire, giving customers UK-produced material alongside our wider stock range. We also manufacture copper busbars to drawings, with cutting, punching, bending, machining and plating on the same site. To work out the weight of a section before you order, try our metal weight calculator, or talk to our team about your requirement.
