[ale] wiring two buildings

[Jared Lyvers]

I would have to agree w/ Jeff, however, being the stickler that I am, I do use
an APC to regulate the flow of not only electrical currents, but also from
between the lan line in our connected office.

<<--start original snipit--
On Tue, 13 Jun 2000, you wrote:
> > I have 2 buildings in a small strip shopping center. I need to tie the
> > networks in the two buildings together. GA Power rep. tells 
> > me to go fiber
> > optic because the buildings are grounded separately. If I 
> > hard wire he says
> > I will blow nic's because of different ground currents.
--end original snipit-->>

<<--start re 1-- 
> He could be right.  Even though both building's grounds *should* be at the
> same potential, in practice, that is probably not the case.  I'd speculate
> that under ordinary conditions, a few volts' difference would waver one way
> or the other between the two, but a passing storm cloud could make the
> difference shoot up - and at the NICs' repsective grounds, that could
> translate to tens or hundreds of volts.  It's not as though that kind of
> potential would express itself across the NICs' cable connector pins
> themselves (the Ethernet cable's conductors "float," IIRC), but if the
> potential difference between grounds got high enough, you've got a
> conductive path bridging things that are PHYSICALLY CLOSE to grounded things
> on both ends, with air gaps, insulator gaps, and semiconductor gaps between
> them, and I'd imagine the semiconductor gaps would break down first.  You
> wouldn't hear as much as a "pop."
> 
> If you want to be an absolute stickler, it's not a matter of ground
> "currents" but ground "voltages."  Currents go "through" but voltages go
> "across."
> 
> So, basically, anything that doesn't involve a conductor will do.
> 
> - Jeff (ex-EE)
--end re 1-->>
-- 
Do, or do not.  There is no try.  --Yoda

Jared Lyvers
System Administrator
Lewis Communications | Birmingham
205.980.0774 x3047
http://www.lewiscommunications.com/employees/jaredlyvers

	|
|__--McGregor--__|
	|
   Jared Lyvers
--
To unsubscribe: mail majordomo at ale.org with "unsubscribe ale" in message body.