[Tfug] Switches -- and hubs!

[Choprboy]

On Thursday 24 December 2009 09:45, Zack Williams wrote:
> On Thu, Dec 24, 2009 at 8:55 AM, Bexley Hall <bexley401 at yahoo.com> wrote:
> I've seen some nasty ground loops from using copper over a long distance.
>
> According to one of my TV engineer buddies, in the late 90's at McKale
> Center you could measure a 9v differential between it's electrical
> wiring ground and the shield on the triax camera cable.
>

During the development of ethernet at Xerox PARC it was noted that there was a 
90V ground differential between the two ends of the building the first 
ethernet cable spanned. Ethernet is an isolated transmission medium, so it 
can tolerate a large differential. I don;t like to do it.. but sometimes you 
have to use copper. In those cases you can get telcom grounding blocks fairly 
cheaply for each end. Throw in a 60V or 90V cutoff arrester on either end and 
you can protect against most but really close/direct strike.


Adrian