Use of aluminum power conductors in industrial wiring
Use of aluminum power conductors in industrial wiring
(OP)
Please help me with comparative advantages and dis- adavantages in using aluminum conductors in industrial power wiring and also transformer winding.
My understanding is aluminum has more resistance and there will be lot more load losses and also we need to use larger size conductor to carry the same current as copper conductor.
I appreciate some references. Are ther any safety issues?
Thanks.
PGBENGR
My understanding is aluminum has more resistance and there will be lot more load losses and also we need to use larger size conductor to carry the same current as copper conductor.
I appreciate some references. Are ther any safety issues?
Thanks.
PGBENGR






RE: Use of aluminum power conductors in industrial wiring
Since the bus bars or terminals you connect to will be copper, you need to make sure to use the right antioxidant grease when making the connection.
It used to be that aluminum cables couldn't handle repeated bending, but I've been told that new alloy formulations allow for flexibility almost as good as copper.
All of the MV and HV overhead wires around here have been aluminum for a long time, and they typically work very well, with few problems. The biggest problem I've seen is that cable splices can overheat and blow apart when the antioxidant grease dries up over time. Periodic thermal inspections of terminations and splices will alert you to any problems like that.
RE: Use of aluminum power conductors in industrial wiring
Aluminum exhibits a property known as "cold flow" where the aluminum will tend to flow out of a compression termination, causing a loose connection that can overheat. New installation techniques and termination devices have basically solved this problem, but it still takes a trained, competent electrician to terminate properly. Copper is much more forgiving.
Aluminum windings in transformers is a little different. The main issue is efficiency. However, a failed aluminum winding tends to produce more core damage inside a transformer than a copper winding, so if for big and/or critical transformers, I would always specify copper.
Just my $0.02. As a consultant, I specify copper for all industrial and commercial work and sleep better at night - unless the client insists on aluminum.
(For electric utilities, 95% of underground 15 kV cable is aluminum - it's more cost effective and they have miles and miles of it, so it makes sense for them.)
RE: Use of aluminum power conductors in industrial wiring
Scramode
RE: Use of aluminum power conductors in industrial wiring
RE: Use of aluminum power conductors in industrial wiring
Solid aluminum conductors, (#12 AWG, the most common residential size, when used) are much more likely to break if nicked when the insulation is removed than copper conductors.
aluminum oxide has a high resistance. If the conductor is not properly cleaned the contact area will be reduced leading to a Hot joint, heat cycling, cold flow and failure.
If moisture enters a connection it can lead to corrosion, high resistance joints and failure.
When copper conductors outdoors are connected to aluminum conductors the copper must be located below the aluminum conductor. Rain water on copper will form copper salts that will corrode aluminum.
If the copper is below the aluminum the corrosion is almost eliminated.
Aluminum terminations require more care, skill and training than copper terminations. Aluminum may be used safely and is used by utilities.
Clean the surfaces well.
Use proper anti-oxidizing grease (immediately after cleaning).
Use generaous contact areas to reduce the magnitude of heat cycling and avoid cold flow.
Avoid connections to dissimilar metal in areas prone to moisture.
A lot of us still prefer copper.
respectfully
RE: Use of aluminum power conductors in industrial wiring
PGBENGR.
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RE: Use of aluminum power conductors in industrial wiring
http://www.kupfer-institut.de/lifecycle/ (hold your mouse over the tab marked Life Cycle and information links drop down)
or the Copper Development Association: http://www.cda.org.uk/frontend/pubs.htm
RE: Use of aluminum power conductors in industrial wiring
Try this.
RE: Use of aluminum power conductors in industrial wiring
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It may be like this in theory and practice, but in real life it is completely different.
The favourite sentence of my army sergeant
RE: Use of aluminum power conductors in industrial wiring
respectfully
RE: Use of aluminum power conductors in industrial wiring
Aluminum is prone to oxidation especially where it terminates. This can quickly lead to hot spots that excerbate the problem.
Special grit grease can be applied to the termination pots but there is still a requirement for occasional inspection and correction of termination points. Therefore the initial lower cost of installation is offset somewhat by ongoing maintenance.
If the aluminum conductor termination is badly damaged it has to be shortened so additional slack is necessary to allow for this possible situation.
Finally there is potential galvanic corrosion issues related to termination with dissimilar metals as there is typically a point along the conductor route where aluminum ends and the copper begins e.g., motors etc.
Many residential and commercial installation only use alumunium conducter as a main feed.
The best solution to control the cost of copper is to keep the heavier conductor runs as short as possible, i.e., keep the largest loads closest to the power source.
RE: Use of aluminum power conductors in industrial wiring