why there is a temperature rise at different metal to metal contact at cable l

why there is a temperature rise at different metal to metal
contact at cable lug??suppose cable is aluminium and the lug
is copper,than why the temperature rise takes place??

Question Posted / som

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why there is a temperature rise at different metal to metal contact at cable lug??suppose cable is..

Answer / k.prakashchandra

It may lead to corrosion at the contact resulting in
contact resistance .Use metal paste.

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why there is a temperature rise at different metal to metal contact at cable lug??suppose cable is..

Answer / nagesh.patwari

Galvanic corrosion-

As moisture can easily enter to the termination point, aluminium conductor, as a reactive metal in
galvanic series, is susceptible to corrosion when aluminium comes into contact with a more stable
material, such as the relatively noble metal copper. Galvanic corrosion is a typical issue for

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aluminium conductor when dissimilar metals are in contact with each other in the presence of
electrolyte. Such deterioration of aluminium can not only accelerate the depletion of conductor, but
also affect the contact behaviour and promote the contact failure.
 The use of dissimilar metals at the termination point is also not good at coping with thermal shock
or high temperature condition which generates incompatible thermal expansions of conductor and
terminal, since aluminium has a relatively high coefficient of expansion than common terminal
metals such as copper metal. Incompatible mechanical/thermal behaviours between terminals and
aluminium conductors deteriorate the connection and eventually cause a failure since dynamic
loads or vibration can be existing over a long time period