Skin effect or total crossectional area

[MR. P]

Two cases:

1. A #12 solid copper wire is rated for 20a and a #12 stranded wire is rated
for 25a the reason given for greater ampacity is increased surface area
of the stranded wire called skin effect.

2. Does/is skin effect a consideration when current passes through a liquid or
is there a different word or consideration which describes this type of
current flow?

 

[willib]

i've done some reading ,in the past , on this subject..
say that you have two metal plates ,in water , and you are passing a current through them .
The resistance is proportional in some way to the distance between the plates , and the make up of the liquid, obviously salt water will have less resistance than tap water, because of the Na+ and CL- ions..
skin effect ? i am not sure..

 

[MR. P]

willib

I have some experience with a process known as 'Static ECM' or static electro-chemical machining. In that arena we would use currents as high as 300a to 500a at 7 -12 volts D.C. for a few seconds usually under a minute to 'machine ' a 'deburred' detent for the spring clips that go into the sychronizer ring for manual transmissions. My curiosity has always been the mechanism of electron flow within the electrolyte, which could be basic or acidic depending upon the type of electrodes or machined material we were using.

frank MR. P

 

[Cliff_J]

Skin effect only happens at high frequencies like radio.

Regular stranded wire has no benefit unless the strands are electrically isolated. Then its called Litz wire.

 

[MR. P]

thank you cliff I'll double check the lead ,so the multi stranding is for cooling? I know that 500KV transmission lines are hollow... for weight and the inside and outside surfaces for current flow...

frank