DC cable construction

**ol' boy** · 24-01-14, 02:02 PM

Seeings as there is lack of Tech posts, i'll ask this questions which might see things down to the molecular level.

With automotive DC cables, they are always superfine multi strand.
Even Welding cables are.

My question is, is this purely for reasons of flexability?
Or is there less resistance for DC currents on a very fine multlistrand cable?

My questions comes from the fact that i have lots of 16mm, 25mm and 35mm cable in the workshop that is used in general wiring, it is multi strand, but each strand would be 2.5mm. Those automotive cables you see connected to batteries, are 16 or 25mm, but would have strands the thickness of a hair.

I understand the "Skin Effect", but i thought that mostly relates to AC current where the frequency determined the diameter of the "Skin".

Does anyone understand this? Is a 25mm conductor made up of 2.5mm strands the same a conductor made of hair thickness strands when it comes to DC current carrying capability and volt drop?

**Downunder35m** · 24-01-14, 03:46 PM

It is a simple matter of vibrations and the ease of handling.
The more flexible a cable is the longer is survives virbrations and bending.
The resistance is totally uneffected as long as the real overall thickness is the same.
Flexible cables make press on connections easier and safer too.
You can say that basically everything that is not totally fixed uses very flexible cabling, whilefixed installations, like inside your home use pretty thick single strands.
In the audio sector they use oxygen low copper cables with even thinner strands claiming it brings a better overall frequency spectrum.