ECN Forum Forums General Topics of the Trade General Discussion Area Stranded or solid

Stranded vs. Solid -- In practical application there's little difference in electrical performance between stranded and solid wire. The DC resistance of stranded wire is slightly more than solid wire of the same gauge, due to the slightly smaller total conductor cross-sectional area. But stranded wire has slightly less impedence at high frequencies, due to the slightly larger surface area. So, stranded wire is generally preferred for most applications because of it's much greater flexibility, but solid might be preferable for high power (and especially high current) applications.

UL will say it's suitable. However I guess the issue of what type of wire vs. type of connector also hinges on what is easier to work with a particular type of terminal.

For instance, when it comes to screw terminals (like those found on wall switches and receptacles), solid is easier to work with once you've got the hook done. You don't have to worry about individual conductor strands coming out from under the screw as it tightens, like it happens when attching a cord cap or a lampholder to a piece of lamp-cord.

When twisting two conductors and attaching a wirenut, stranded is easier because you can twist it partly with your fingers - you don't need a linesman's pliers.

There is a lot of myth about where current flows.

I suspect that A/C current that flows at the surfaces of stranded conductor refers to current that flows near the insulation of the conductors rather than at the surfaces that are interior to the whole wire.

I suspect that there is no real current carrying difference between identical x-section stranded and unstranded wire.

The only difference is: Stranded is easier to bend.

Skin effect is neglible to non existent at and below 60Hz, until you get into the 250kcmil and larger wire sizes.

Skin effect is a function of the frequency, and the overall diameter of the conductor. As far as skin effects goes, it makes no difference if the conductor is solid or made up of strands.

When is skin affect needed? How about antenas, I see that they are hollow and work at a very high frequency.