MIKE ROSS wrote in a message to Steve Asher:

 MR> For 60 Hz AC the skin depth is about 1/3 of an inch. The greater
 MR> part of the current flows in this outer area but the total current
 MR> flows out to about 5 skin depths, less and less as it goes deeper.
 MR> Below this 5 skin depth no current flows and the wire may as well
 MR> be hollow or made out of steel, which is exactly what is used to
 MR> make the cables strong. 

I've seen this claim before,  probably in here some time back,  but that's
the first time I've actually seen it quantified like that.  A third of an
inch,  huh?

---