# Copper wire resistance

Discussion in 'General Electronics Chat' started by impetey, Jan 10, 2004.

1. ### impetey Thread Starter Member

Jan 10, 2004
11
3
hello,
Do any of you know: For a given nominal AWG of pure copper conductor round wire, which has the higher resistance per 1000', stranded or solid? Do surface eddy current effects play a role on very small diameters vs large? :huh:

2. ### Battousai Senior Member

Nov 14, 2003
141
44
By stranded, do yuo mean copper conductors twisted together?

I don't know what the difference would be (I imagine they'd be pretty much the same thing), but wouldn't pure copper wire give you better performance?

What frequency are these wires used at?

3. ### Dave Retired Moderator

Nov 17, 2003
6,960
146
For practical uses the resistance would be the same. If you were being picky you'd probably find the resistance of the stranded wire would be marginally greater (possibly in the realms of milli-ohms) due to a slightly smaller cross-sectional area.

As for eddy currents you may need to elaborate on the details for us to say whether it would have an effect on small or large diameters:

Eddy currents are often generated in transformers and lead to power losses. To combat this, thin, laminated strips of metal are used in the construction of power transformers, rather than making the transformer out of one large solid piece of metal. The thin strips are separated by insulating glue, which confines the eddy currents to the strips. This reduces the eddy currents, thus reducing the power loss. So you can see that in certain circumstances small diameters are desirable with respect to eddy currents.

4. ### sbgarkar New Member

Jan 12, 2004
1
0
D.C. resistance of a given cu wire is a fixed value and will vary with temperature.however with high currents or frequency the self inductance or skin effect will come into play thus exibiting a higher a.c. resistance in a solid conductor than a stranded conductor.