Does stranded wire reduce resistance from skin effect when strands are not insulated?

Question

I've seen many discussions where people mention multi-strand wire improving conductivity when skin effect is a concern, but I often see Litz wire mentioned in these discussions. Litz wire contains individually insulated strands of wire. I haven't found anyone clearly explain whether or not the individual strands have to be insulated to reduce resistance from the skin effect. Can someone clarify this for me?

For specific application, I have a lot of 10 AWG multi-stranded wire. The conductors are bare strands all held in a THHN jacket. This is common stuff used in regular electrical wiring, but I want to use it for audio frequency application. Will the individual bare strands improve conductivity versus a solid wire in this case?

Skin effect at 10kHz is ~0.6mm, so unless the copper core is larger than 1.2mm diameter, skin effect won't have any effect at all. At such low frequencies it will be negligible anyway even if the wire is larger. — Tom Carpenter, Dec 31 '16 at 22:10
It *is* larger than 1.2mm. 10 AWG wire is 2.588mm diameter. So the strand issue matters. — JamesHoux, Jan 01 '17 at 00:11

score 7 · Accepted Answer · edited Dec 10 '20 at 06:13

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The answer is "yes", even a non-insulated strands are better than solid round copper, because the strands have limited contact area between each other, and field distribution is better, reducing skin effect. See this study, Stranded Wire With Uninsulated Strands as a Low-Cost Alternative to Litz

edited Dec 10 '20 at 06:13

feetwet

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answered Jan 01 '17 at 03:38

Ale..chenski

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Thank you for the excellent paper, Ali. The analysis of wire pitch clears up everything. – JamesHoux Jan 01 '17 at 17:57
That link no longer appears to work. I found the same paper here: https://w5jgv.com/hv-ps1/pdf/stranded.pdf – Trashman Aug 10 '23 at 18:50

Does stranded wire reduce resistance from skin effect when strands are not insulated?

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