"Roy J. Tellason" wrote to "ROBERT SAYRE" (26 Dec 02  12:06:02)
 --- on the topic of "HVDC Transmission Lines"

 RS>  I always thought that the skin effect was negligible at low (60Hz)
 RS> frequencies.

 RJT> Same here.  There's no doubt a formula for it in some book around
 RJT> here,  but I have no idea which one,  nor the inclination to dig it
 RJT> out at the moment...   :-)

You lazy sob!... 

From "MICROWAVE ENGINEEING" By David Pozar c 1990 Addison Wesley
(P. 27)

Skin depth (meters):

ds=Sqrt(1/(PI*f*Mu0*sigma))

where sigma is conductivity of material in q.

 pi=3.141
  f=60
Mu0=4*PI*1E-7
sigma for copper(Cu)=5.813E7

Skin depth for Cu at 60 HZ is 0.0085221 metres or 1/3 of an Inch.

It's indeed negligible for house wiring but becomes significant for
power transmission cables having 2 inches in diameter.

 Mike
 ****

... Now touch these wires to your tongue!
--- Blue Wave/DOS v2.30