Article,
Electrical connections for high current applications
CEGB Research, (1988)
Abstract
Aluminium is being increasingly used for electrical
conductors and in many applications, for example
medium and low voltage cables, busbars and earth strip,
it has replaced copper to a very significant extent.
Stability of cost and low weight are major factors which
have contributed to the widespread adoption of aluminium.
It is not always appreciated that to connect
or 'joint' aluminium successfully, greater attention to
joint design and assembly is necessary than with copper
conductors. The reason for this is associated with the
tenacious oxide film which forms on aluminium surfaces
exposed to air. Also the relatively poor mechanical
properties of electrical grade aluminium can cause
relaxation in service of the applied clamping pressure.
This article considers the nature of surfaces in contact
and how this knowledge may be used to optimise the
performance of connections. Diagnostic testing of
connections is still an important activity in ensuring that
high resistance connections are detected be/ ore failure
occurs and recent developments in this area are
described. The article concludes with a description of a
successful new 'jointing' technique for aluminium
busbar which is particularly suited to the characteristics
of this material.
