On Oct 24, 2007, at 10:54 PM, John Winterflood wrote:
The important thing about a Faraday cage is that inside it you
cannot tell anything about electric fields or electric potentials
that exist outside. You can't tell (in theory at least) whether
the cage you are in is grounded, or sitting at 100kV, or on the top
of a Tesla coil and being oscillated plus and minus to many megavolts.
In this Ron's case however there is an "ground" wire entering the
cage and who knows what potential difference exists between the
cage and the wire entering it until he measures it. This is the
important thing - it doesn't matter whether either or neither are
grounded - it just matters what is the AC and DC difference in
potential between the wire entering and a well constructed cage.
Good point. Another option along the same lines might be to simply
strip a section of the ground wire and connect the ground wire to the
faraday cage at the entry point using an alligator clip. It the
lights go out then the power is from an external source.
Horace Heffner
http://www.mtaonline.net/~hheffner/
