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I have been trying to understand wire gauge for a project, but there are so many different strand types and sizes it's alittle overwhelming. The wire needs to be 30 AWG and stranded, is it common for 30 AWG to have 7 strands or can it have more like 26?

Michael Karas
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Lanegreens38
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  • It can have as many strands as the manufacturer is willing to do – PlasmaHH Jul 20 '18 at 10:46
  • Ok understood, would there be much difference in a 7 strand cable Vs 26 strand? Flexibility / data transfer wise. – Lanegreens38 Jul 20 '18 at 10:56
  • Flexibility yes, but the isolation is probably the limit here anyway. Data transfer is highly unlikely. – winny Jul 20 '18 at 11:06
  • So would a higher strand count have increased flexibility or the lower count? Sorry for all the questions, but why would the isolation be the limit, due to the diameter? – Lanegreens38 Jul 20 '18 at 11:10
  • Resistance is only determined by area (mm^2). Flexibility and fatigue life are improved by more, finer strands. Cost, corrosion resistance are improved by fewer. House wiring (not flexible) is 2,3 or 5 strands each 0.5mm^2. Hookup wire (flexible, but fixed in use) is 7 strands. This soft Multimeter wire has up to 1050 strands https://www.aliexpress.com/store/product/20M-high-temperature-flexible-silicone-wire-color-option-16awg-silicone-wire-Multimeter-lead-wire-cable/2134116_32878526213.html – Henry Crun Jul 20 '18 at 11:47
  • Ah ok thank you for that information, I'm slowly learning. This cable: https://m.ebay.co.uk/itm/25-Meter-Stranded-Wire-Red-0-05mm-LIFY-Copper-Stranded-Wire-Cable-on-a-Reel-/382356424432?txnId=907241040025 says "Strand - 26 x 0.05 mm" so I'm presuming that is 26 strands and the 0.05 is the size of the strands? The other cable I am looking at in comparison has the following "30 (7/38) AWG TC" with this cable I guess that means 7 strands, but what does the 38 mean? There are so many terms to learn. – Lanegreens38 Jul 20 '18 at 13:09
  • The 38 in 7/38 means the 7 strands are composed of 38 AWG. The total cross-sectional area is 30 AWG. You will see this written as 7x38 often. Typical stranding is 7, 10, 16, 19, 26, 37, 41, 65. On something as small as insulated 30 AWG wire, there is not going to be much difference between 7 strands and 26 strands. – davidmneedham Jul 20 '18 at 14:30
  • Thanks for clearing that up, I was seeing it often when looking for this cable. I have also saw it wrote are 26 strands then 0.005, which was throwing me off. Still on the hunt for 30 AWG/ 26 strand wire, I have emilaed around, but alot of these resellers only stock the 30 AWG/ 7 strand sadly. – Lanegreens38 Jul 20 '18 at 15:07
  • The cross-sectional area of 30 AWG is equal to about 0.051 mm². The eBay listing you linked to shows a 0.05 mm² area and 26 strands, so each strand has a cross-sectional area of about 0.002 mm². A round wire of diameter 0.05 mm has that cross-sectional area. It's coincidence that the 0.05 numbers are the same for both, but one represents area and the other represents diameter. – davidmneedham Jul 20 '18 at 16:31

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The stranding is more-or-less arbitrary, determined by the sizes of individual conductor that the manufacturer can make and how they are combined. The differences are (almost) entirely physical, electrically there is very little difference between a wire with many strands (all touching each other) and one with a single core.

Mechanical characteristics include:

  • flexibility
  • lifetime when bent
  • break strength
  • corrosion resistance (as mentioned by @Henry Crun)

The first two generally increase with the number of strands (but the insulation also can have a large effect).

Diameter variations with stranding will affect the electrical characteristics (eg. inductance, capacitance) only slightly, and rounding from the nominal gauges of strands leads to some slight difference in nominal resistivity though the target is the same resistance per unit length (because the total cross sectional area of the conductors should be the same regardless of stranding).

Eg. an AWG30 wire has a nominal cross-sectional area of 0.0509mm^2. If there are more than one strand then they should add up to that area.

For example, here is an excerpt from the standard stranding chart of a specialty wire manufacturer:

enter image description here

They offer as many as 40 strands of AWG46 wire (as standard). The nominal OD increases for coarse stranding in particular, but in this case only by about 20% for the coarsest stranding.

This particular maker can make single core wire as fine as AWG 56 so you might imagine that (for enough money, and it would be a large amount) they could make an AWG 30 conductor with ~420 strands of AWG 56 wire.

Note that this only covers the conductor. The insulation system is another subject entirely and pretty much independent of the conductor.

Spehro Pefhany
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  • Thank you very much for that detailed response! So for my situation I need a flexible 30 AWG cable, so with the Information you provided the higher the strand count will mean increased flexibility, the cable I was looking at is AWG 30 with 26 strands 0.005 cross section, so it should be quite flexible. Unfortunately the seller doesn't have all the colours I need, where would be the best place to source this, such as the high strand count maker you mentioned? – Lanegreens38 Jul 20 '18 at 13:23
  • For hobby purposes you're just going to have to shop around. I don't have any magic supplier list. Ten colours is a pretty good selection. Beyond that it often gets to stripes or spots, difficult on a #30 wire. – Spehro Pefhany Jul 20 '18 at 13:39
  • You may want to look into purchasing [ribbon cable and stripping it](https://electronics.stackexchange.com/questions/82054/how-to-strip-a-ribbon-cable) – davidmneedham Jul 20 '18 at 14:35
  • Though usually ribbon cable repeats after 10 colours. – Spehro Pefhany Jul 20 '18 at 14:56
  • The colours that are needed are Green, Black, Red and White which are common, what isn't so common is a strand count above 7 for a 30 AWG cable sadly. Although as @davidmneedham stated there is probably not much a difference. – Lanegreens38 Jul 20 '18 at 15:03
  • For other people searching, there is one other characteristic to take into account with solid vs stranded, and that is the skin effect. For the 30 AWG wire in this question, skin effect is negligible but if you have larger gauge wire, it can be significant. Here's a StackExchange article talking about it: https://electronics.stackexchange.com/questions/277825/does-stranded-wire-reduce-resistance-from-skin-effect-when-strands-are-not-insul unfortunately, the article link in that answer no longer works, here's a link that works today: https://w5jgv.com/hv-ps1/pdf/stranded.pdf – Trashman Aug 10 '23 at 18:48