In article ,
wrote:

This whole topic area seems to be eternally confused and confusing and
I'm in the parade of the confused. On a common sense basis I
absolutely agree with your connecting the station grounds to the
'lectric service entrance ground for the reasons you've stated.

But somewhere along the line somebody in the ham groups stated that
the National Electrical Code states that there shall be one and *only
one* grounding point per power drop and the neighborhood code cops and
the insurance companies reportedly get stiff about it.

So is it legal to connect a phalanx of ham station ground rods to the
service entrance ground?? Or not.

As I understand it, according to the NEC, you must have only one
grounding *system* per building. This system may include two or more
ground rods, and/or a bare grounding wire buried in a trench around
the outside of the building. The ground rods and wires must be
securely bonded together with heavy-gauge wire... that's what ensures
that it's all one grounding "system".

What's dangerous is, as has been suggested, having separate grounding
rods (or grounding subsystems) which aren't well-bonded together. If
you connect any electrical apparatus to two such grounding points
(e.g. ham radio with a third-prong ground on its line cord, which is
also tied to a separate ground rod via the coax feedline), and a
lightning strike or a hot-to-ground fault occurs, your electrical
apparatus and its wiring can end up carrying a lot of current between
the ground points, thus creating a shock or fire hazard.

The bonding wires create a low-impedance path for such fault currents,
minimizing the voltage differential which exists between the ground
rods and thus helping keep down the flow of fault current through
undesired paths (e.g. your ham rig).

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
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