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bud--

On 11/27/2013 10:46 PM, wrote:
On Wed, 27 Nov 2013 21:14:26 -0600, wrote:

When the phone company installed my outdoor phone connection box, they
installed a separate ground rod. But the one for my electric panel is
50 feet away. I'm running my own phone line from my house to another
building at quite a distance. I intend to install another outdoor box
with built in lightning protection. (same as the one from the phone
company). The ground rod from my electric service is 6 feet away. Is
there any reason not to use the same rod? It dont seem to make much
sense to drive in another rod.

Note: I intend to also ground a tv antenna to it.

The NEC requires that ALL ground electrodes must be bonded together.
It is also the recommended practice for lightning protection.
If line powered telephone equipment is the only place here this bond
occurs (incidently) that will be where any difference is reconciled.
Back in the modem days, separate grounding systems was the most common
cause of smoking modems PCs etc

The same is true of satellite installations. They usually drive a
separate rod. You should bond this to your grounding electrode system
for the service.

This is a major point for protecting equipment.

You want a single earthing system with a single connection to the house,
and short wires from entrance protectors to that earthing system.

During an "event" the ground rod 50 ft away may be many thousands of
volts different from the house. That voltage shows up at equipment
connected to both phone and power. I would put a second phone entry
protector at the house and connect it to the house earthing system.
There is no direct connection from protectors to the phone wires so
there should be no noise introduced.

Bonding the rod 50 ft away doesn't work as well as you might think. You
could have a relatively large current through the bond wire during an
"event" since that ground rod is part of the earthing system. Lightning
has relatively high frequency components, so the inductance of the wire
is more important than the resistance. The inductance doesn't decrease
very fast as you increase the wire size.