The great debate: Copper versus aluminium

By E Swanepoel, Copper Development Association Africa (CDAA)

 

Published in:

Electricity+Control, December 2013 (pages 28 - 30)

Enquiries: evert.swanepoel@copperalliance.org.za

 

Download the full article on The great debate: Copper versus aluminium in PDF format.

 

The pros and cons of copper versus aluminium conductors have been debated for many years. The concerns centre on the very different properties of the two materials and their suitability for application within the electrical equipment industry.


Reliable performance from the conductors, the joints and terminations of the conductors, is essential to the operation of the electrical system.

In 2003, a study was conducted for the Canadian Copper and Brass Development Association (CCBDA) in Toronto by Powertech Labs of Surrey, BC. The objective of the study was to compare the connector performance under equivalent, severe environmental conditions for three configurations: copper connectors on copper conductor; aluminium connectors on copper conductor; aluminium connectors on aluminium conductor.

When copper and aluminium are brought into direct contact in the presence of moisture, a strong galvanic reaction takes place due to the dissimilar properties of the metals. Therefore aluminium connectors cannot be used with copper conductors unless an interface material, which is more compatible with both copper and aluminium, such as tin, is present. However, tin is also susceptible to oxidation and if the tin layer is compromised, then galvanic corrosion between the base metals can still occur.

The differences in properties of copper versus aluminium may result in a significant performance difference in the various types of electrical connectors in long term service.

For the study, copper-to-copper, aluminium-to-copper and aluminium-to-aluminium connections were subjected to accelerated ageing, which consisted of 2 000 hours of environmental exposure and high current, short time testing. The copper connectors on copper conductor had very little change in resistance during testing and performed the best in the study.

 

Take note:

  • Many concerns in the copper versus aluminium conductor debate are based on outdated and incorrect information.
  • A study conducted by the Canadian Copper and Brass Development Association compared the connector performance under equivalent, harsh environmental conditions.
  • The configurations were copper connectors on copper conductor; aluminium connectors on copper conductor; aluminium connectors on aluminium conductor.