[dillondf]

Well, I probably don't have to tell people to never run copper between buildings. Always run fiber. The longer the runs, the higher the common mode voltage between grounds and the higher the stress on the isolation circuitry. Plus lightning strikes don't have to hit the cable directly, they can pull up the ground for the whole building and suddenly instead of having 200V of common mode you have 4000V for a few milliseconds.

Anyone who has ever wired up a T1 in the basement of a highrise knows what I mean.

-Matt