> Has anyone heard of such a thing ? Or any ideas, like could it be
> a poor Telco ground ? It's been very frustrating.
I would definitely suspect the Telco ground.
First check to see how the primary building ground is done. If it's
bonded to an incoming copper water line, then it's probably ok. If it's
using a couple of driven rods in dry or stoney soil, or the connections
are corroded, then the primary ground is likely to be weak.
Next check the Telco ground. See if it's tied to the electrical ground,
or is separate. Again look for dry soil or corroded connections.
If these checks turn up some possible weaknesses, then a trick you
can try yourself is to buy some rock salt, pour it on the ground around
the rods, and then give the area a good soaking. This will leach out
depending on the amount of rainfall, so should be repeated every few
months. Even better is to buy about 5 kg of copper concentrate from a
mine. This stuff doesn't leach out like rock salt, and can get you a
low impedance earth connection in drilled granite.
To get a hard number on it, call in an electrical contractor who can
do what's called a ground impedance test. This uses a special tester
which applies a low level AC current between a test rod and the
grounding rods. The result should be < 9 ohms impedance. If it's higher,
get the contractor to check out the earth system from top to bottom, and
possibly drive in more rods.
What you should NOT do is power the UPS system from one of those
orange isolated-ground computer receptacles. These things are the
biggest con going, and most electricians aren't aware that they are
next to useless. What you should have is a standard receptacle wired
with a cable that has a #10 A.W.G. ground wire. Since regular 15 and 20
amp cables only have a #14 A.W.G. ground wire, this would require the
receptacle to be wired with conduit and individual wires.
If you want more info, send me an email message. I have Canadian
master electrician papers and have done lots of work on bonding in
electronic environments.
Regards,
Brian.
Corbin Network Services, Inc.
Box 1960, Sparwood, BC, Canada
V0B 2G0
Member, Canadian Association of Internet Providers
Network operations, programming, and training.