Al vs. Cu

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
Is there any reason why I wouldn't want to change over all wiring in PV systems from Cu to Al? Even for short runs, since we do a whole lot of them, it would save us a ton of $$'s.
 

user 100

Senior Member
Location
texas
Is there any reason why I wouldn't want to change over all wiring in PV systems from Cu to Al? Even for short runs, since we do a whole lot of them, it would save us a ton of $$'s.
I don't see where it would hurt anything at all- the same rules about al apply whether used in solar or in grid- oxidation concerns ( a non issue- the alloy today is different and there are solutions if really a concern- nolox, etc), al needs to be bigger to carry same amt of current than copper (so maybe larger raceways, but probably that xtra $$$ cancelled out by savings on copper), appropriate connectors/ terminations, don't nick the al.... and all that other good stuff you already know about.:)
 

Carultch

Senior Member
Location
Massachusetts
Is there any reason why I wouldn't want to change over all wiring in PV systems from Cu to Al? Even for short runs, since we do a whole lot of them, it would save us a ton of $$'s.
For circuits that are 100A and less, you will often find equipment that specifically requires copper. String inverters, MC4/H4 connectors, etc.


Over 100A, most terminations are dual rated for both Cu and Al, so it is less of a concern.
 

310 BLAZE IT

Senior Member
Location
NJ
Aluminum on AC home runs is what we do. Depending on the length you may have to use reducers to make the terminations, since you're likely using a larger wire than the breaker typically allows for (both aluminum and upsized for voltage drop) It's hardly a downside but worth mentioning.
 

pv_n00b

Senior Member
Location
CA, USA
As long as you follow the installation requirements you can use Al conductor. You may find, as Carultch wrote, that a lot of PV equipment that terminates smaller conductors is Cu only. Since Al is not usually used at smaller sizes the manufacturers do not add dual rated terminals.
 
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