Eugen Leitl <[EMAIL PROTECTED]> writes: > On Sun, Jul 27, 2008 at 07:19:56PM -0700, Jim Lux wrote: > >> bear in mind that ordinary ethernet both coax and twisted pair is >> galvanically isolated. > > This is strange, because I've seen (small) sparks and received (mild) > shocks from both, in two different locations.
Ground loops are a real phenomenon in UTP Ethernet. For example, *NEVER* run UTP between buildings. If the grounds in the two buildings are at a different relative potential, and they often are, very bad things can happen. The building complex I live in ran Cat 5 between buildings in underground ducts. They were very surprised when lightning strikes some distance away regularly blew out the switches. Changing to fiber eliminated the problem, of course. > In any case I'll have an electrician diagnose the problem. If you're seeing sparks, as you say, I suspect you do indeed have an AC supply problem. Ground loop, or something worse. (The Electrical Wiring FAQ describes several problems that qualify as "worse"...) -- Perry E. Metzger [EMAIL PROTECTED] _______________________________________________ Beowulf mailing list, [email protected] To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
