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I always thought stranded wire carried less current than solid... Just read an article saying that the overall size of stranded wire is typically 8% larger than solid core, and the cross-sectional area of solid vs. stranded is the same. So what you said makes sense, but how much more current can typically be handled, and how does oxidization come into effect... (I've stripped automotive wiring that has had oxidized a few inched up into the insulation from the connector.)I've always used the rule of thumb that 1 sq inch of copper can carry 1000A for the metric conversion, 1.6A per mm2 is close enough.
This doesn't take into account cooling based on the larger relative surface area of finer wire though so you'll find that thinner wire can carry significantly larger current that this rule of thumb would suggest..
Forgive my ignorance on this one, but if current only flows on the surface of a conductor, than why do we see a cross-sectional area used to determine current flow limits instead of a perimeter?According to SAA wiring, and it was cross section area I was referring to, 1.5sq mm carries 15amp.
Although , as I also said, the value is not linear. 600 sq mm is around 700 amps.
If you have corrosion then it will be a setback as current flows in the first few microns of the surface of the conductor.
May well be said that cable could be made of steel with just a thin film of copper (earth stakes are actually made that way)
and I'm certain that cabling these days is not the same copper as was used say 20 years agne can compare old and new from older installations.
The overall size of "some" stranded cables is larger due to the air gaps between the conductors.
This is why they produce "compressed" cable as it is much smaller but the same cross section area, but a real mother to use.(very stiff)
Yes, was a surprise to me also but apparently thats how it works.Forgive my ignorance on this one, but if current only flows on the surface of a conductor, than why do we see a cross-sectional area used to determine current flow limits instead of a perimeter?
I also understood ground stakes to be copper plated to help reduce/prevent corrosion.
Sorry, these are not things I can really answer. I believe Wikipedia has answers for the first of these.. So what you said makes sense, but how much more current can typically be handled, and how does oxidization come into effect...
Found an answer on EP. It goes with my new understanding. The additional current carrying capability is dependant on the AC frequency in question due to the skin effect.Sorry, these are not things I can really answer. I believe Wikipedia has answers for the first of these.