3 ms·
Big problem with aluminum is that it has less conductivity and thus is generating more heat in same diameter. However heat and air will cause aluminum cable to
by TheLoafOfBread 4y ago
Big problem with aluminum is that it has less conductivity and thus is generating more heat in same diameter. However heat and air will cause aluminum cable to oxidize and as a result it will get
1) brittle to point of falling apart.
2) increases it's resistance through oxidation, which will increase heat
This is a big problem in Eastern Europe where communist were building concrete apartment towers wired with aluminum wires, it used to be major reason for fires before those towers were reconstructed and aluminum replaced by copper. Today it is forbidden to use aluminum wires in apartments and houses.
Aluminum is more-less unusable in installations where you can't shield it from air and where aluminum will heat up.
- sudosysgen 4y agoYou can compensate for conductivity with larger diameters (modulo the skin effect, but there are options there too). At that point wires don't heat up so much and thus don't oxidize.
- amelius 4y agoDoes skin effect even play a role in power delivery? We're not talking about high frequencies here, I suppose.
- tuatoru 4y agoYes, it does, at distances of thousands of km and 50 or 60 Hz. One of the reasons why high-voltage DC is preferred over those distances.
- tuatoru 4y agoAlso use higher voltages, and therefore lower currents. Heat losses are proportional to the square of current, so relatively small voltage increases fix the problem. > Aluminum is more-less unusable in installations where you can't shield it from air and where aluminum will heat up. Your power was probably delivered over hundreds of km of uninsulated steel-cored aluminum wire.
- TheLoafOfBread 4y agoSo that's the reason why all aluminium wirings in buildings were ripped off and replaced with copper?
- sudosysgen 4y agoAluminium wiring is still being used in buildings around the world. If the country where you're from banned aluminium wiring for some odd reason, it's probably that the wiring was defective and they couldn't legally or practically replace it with anything except copper wiring.
- TheLoafOfBread 4y agoWe used to use aluminum wirings for apartments/houses in Eastern Europe during communism because it was cheaper. It turned out that it does not work, it oxides, it will cause fires in buildings. Now it is outlawed. Usage of aluminum in any small and high power electronics will cause exactly same issues for exactly same reasons
- sudosysgen 4y agoIt is a matter of fact that aluminium wiring for appartements and houses is fine as long as the wires are correctly specified for the load. It works. There are plenty of houses with aluminium wiring that have stood the test of time and plenty more which will. It's not rocket science. Aluminium is slightly less conductive so you have to make the diameter bigger (and coat it, etc...). When you do that, it is fine. Aluminium can be and is used in smaller, high power applications, especially when weight is a concern, as it has a higher conductivity per unit mass than copper. The issue with aluminium wiring in practice is not the aluminium oxidizing. Aluminium oxidisation is self limiting. It is an improper connection leading to a few nanometers of oxidation at the connection site, and thus higher temperature at the site of connection leading to a fire. This is avoidable but some places feel it is easier to ban aluminium wiring than enforce proper electrical connections.