 
Copper is the most efficient and reliable electrical conductor for
commercial and industrial wire and cable. When compared to aluminum,
copper has a significant (1.6 times) ampacity advantage, is easier
to install, and is resistant to corrosion. Contrary to aluminum, copper
is a very forgiving metal to join electrically, and copper connections
have never been the weak link in a wire or cable system.
Copper wins conductivity and strength contests. Copper has
the highest electrical conductivity of all engineering materials.
A copper cable of specified ampacity is smaller than an aluminum cable,
and it is easier and less costly to install. Copper conductors are
harder and stronger than aluminum alloys, and are more resistant to
nicks and mechanical abuse during cable installation. This is a real
advantage at junction and termination boxes, where copper conductors
can be bent further, twisted tighter, and pulled harder without stretching
or breaking. Conversely, aluminum is softer, has a lower modulus of
elasticity, and cold-flows away from a stressed area when connected
under high pressure. Properly made copper connections run cooler than
their aluminum equivalents, ensuring that copper connections will
have a longer life.
Copper is easier to install. Since a copper cable can have
a smaller diameter and more flexible insulation, armor, and jacketing
than aluminum cable, it is more flexible and requires less effort
to bend into position during installation. Since copper cable is less
bulky than aluminum, transport of the cable to the installation site
is much easier.
Copper is corrosion resistant. In the presence of moisture,
aluminum alloys will corrode. This susceptibility to corrosion shortens
the life of aluminum cables. Furthermore, water in contact with an
aluminum conductor of an insulated wire or cable will result in severe
corrosion. The oxidation of the aluminum to a hydroxide leads to damaging
expansion of the cable insulation structure and eventual destruction
of the cable. The hydrogen gas produced during this reaction can be
damaging.
Alternatively, moisture in a copper cable will not cause serious corrosion.
Aluminum conductors require special protection and cannot be used
as equivalents or replacements for copper in critical applications.
This is why the Canadian Electrical Code only allows copper conductors
to be used for fire alarm and fire pump circuits.
Copper has a less expensive life cycle. The true cost of a
cable, often referred to as its "life cycle cost," includes the preliminary
cost of the cable, as well as the cost of installation, maintenance,
repairs, and replacement. While aluminum cable wire is sometimes less
expensive to buy than copper, aluminum cable is more difficult to
install and is more prone to failure. Therefore, the full life cycle
cost of copper cable is lower than aluminum cable. |
