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Why aren't stranded copper coated aluminum cables (CCA) widely used outside a small niche of speaker wires or 12 VDC applications?

According to this post the issue is with the insulation jacket which is either PVC or silicone and rated at 600 V.

I am asking because I want to contribute to this problem solving challenge by suggesting that multi-stranded wires are better conductors because they don't heat up due to a higher surface area, have no skin effect, and have overall lower resistance.

My suggestion is to replace NM wires in homes with multi-stranded CCA cables similar to this one. If the jacket is a problem surely engineers can find ways around it. With electric cars coming to more houses, we need better cables I think.

Next step is to replace low, medium, and high voltage power lines with the same multi-stranded cable. The low voltage lines are easy since they are sheathed.

For medium and high power I think that putting a soft multi-stranded cable inside this hard trapeze cable should work. These issues could be figured out if there is significant improvement in power transfer/loss. I feel when you need 700 kV to push 1 kA current through large regional power lines you're fighting the wire, because as wires heat up the conductivity goes down. With multi stranded wires there is no heat build-up.

Why is multi-stranded wire not used more widely if it's economically and electrically a better wire? Is it because it's too new?

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    \$\begingroup\$ seems like initial applications for that challenge are closed, so I'm not sure you'll be able to contribute. The skin effect will still occur unless the strands are insulated from each other, which sounds like a pretty big hassle at high voltage. Also, stranded wire doesn't really have a much higher surface area from a heat transfer point of view, unless you separate the strands enough for air to get inbetween them, which is an even bigger hassle \$\endgroup\$
    – BeB00
    Commented Aug 8, 2022 at 2:52
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    \$\begingroup\$ Where are you getting the idea that "conductivity is improved", and compared to what, exactly? Where are you getting the even idea that "there is no heat buildup"? Or that stranded wire is a "new" technology (hint: it's older than electricity)? Or that non-Litz stranded wire offers a noticeable improvement to skin effect? \$\endgroup\$
    – hobbs
    Commented Aug 8, 2022 at 2:53
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    \$\begingroup\$ also more specifically, this competition is about developing new materials and technologies. It's the sort of thing that typically involves cutting edge material science and physics research and lots of people with phds. That's why the prize is $2m and the selected teams are all using carbon nanotubes or exotic metal alloys etc \$\endgroup\$
    – BeB00
    Commented Aug 8, 2022 at 2:56
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    \$\begingroup\$ Stranded wires do not defeat the skin effect. Litz wire does. Aluminum wire is much cheaper than copper wire but it has a reputation for problems in the context of home wiring. There were a lot of house fires caused by aluminum wire connections degrading over time and becoming high impedance. \$\endgroup\$
    – user57037
    Commented Aug 8, 2022 at 3:10
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    \$\begingroup\$ Amazon product information and reviews are not reliable and in this case by someone who is clearly not very knowledgeable on the subject of wiring. Why don't you look up a source with verified and verifiable information? \$\endgroup\$
    – StarCat
    Commented Aug 8, 2022 at 7:10

1 Answer 1

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multi-stranded wires are better conductors because they don't heat up due to a higher surface area, have no skin effect, and have overall lower resistance.

This is not correct for house wiring. At the low frequency and wire diameter required skin effect is not a significant factor, and solid copper is more conductive than stranded wire of the same overall diameter. More importantly it is much cheaper.

Stranded vs. Solid Wires: The Key Differences

  • Stranded vs. solid wire current capacity. Solid wire is thicker, which means less surface area for dissipation. The thinner wires in stranded wire contain air gaps and greater surface area with the individual strands, translating to more dissipation. When choosing between solid or stranded wire for house wiring, the solid wire offers higher current capacity.

  • Routing. Stranded wires offer superior bendability and flexibility, making them easier to route around obstacles than solid wires.

  • Flexibility. Stranded wires are more flexible and can sustain more vibration and flexing without breaking. Solid wires may require more frequent replacement than stranded wires in applications with significant movement or vibrations.

  • Cost. The production costs of solid wire are much lower than stranded wire, which makes solid wire the more affordable choice.

For mains wiring having a few strands helps with routing in tight spaces and can make it a bit less prone to breaking. Wires with many strands are used where great flexibility is required, and where the wire may be moved around regularly or suffer high vibration. But wires with many strands can be more difficult to connect to, since the individual strands are thinner and more delicate.

My suggestion is to replace NM wires in homes with multi-stranded CCA cables similar to this one.

Let's check the specs:-

  • Color 4 Guage Wire
  • Ethernet cable category Cat 5
  • Gauge 8.0

Hmmm...

I am asking because I want to contribute to this problem solving challenge by suggesting that multi-stranded wires are better conductors because they don't heat up due to a higher surface area, have no skin effect, and have overall lower resistance.

I think they are looking for a little more than just 'suggestions' for the use of existing products.

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