Now that most of the snow has melted here in W. Michigan (although more
is forecast for tonight) and I have been able to get a better look at
the existing grounding arrangements, I have noticed that a heavy
stranded copper wire comes out of the ground alongside the conduit that
goes to the electricity meter; it then disappears between the slab and
the siding, so I assume that this is the ground connection to the ground
bus in the panel -- correct? If so, do I have to bring my separate
ground connection (from a radio installation, including a future antenna
tower) up into the panel, or can I simply bond it to that existing
accessible ground conductior outside the house?

The gas meter and telephone network interface are on the opposite end
wall of the house. The first thing I noticed is that an insulated wire
that comes out of the ground alongside the gas pipe is simply twisted
around it, with the bared end just "flapping in the breeze"; there are
no marks on the pipe to suggest that the wire was ever clamped to it.
Should I install a clamp myself, or should I call the gas company? (The
telephone interface box is just a few feet away from the gas meter, but
the wire that disappears into the ground from it has a different color
insualtion from the one wrapped around the gas pipe, so I don't think
the floating wire is supposed to be the ground for the telephone.)

But one other question comes to mind: can I really believe/assume that
these existing grounds are all connected together already? Is there
really a conductor running the 60ft or more from the gas meter and
telephone interface at one end of the house to the electricity meter at
the other end? How can I be sure?

MB

I wrote:

I understand that the NEC requires that all grounds (e.g., lightning
protection grounds and grounds for radio transmitting equipment) must be
bonded to each other and to the utility company's ground. The books I
have read say this is accomplished by connecting everything to the
ground "at the service entrance panel." But how is this to be
accomplished? By clamping the ground conductors to the conduit (after
cleaning it down to bare metal) that comes out of the ground and up to
the meter on the wall of the building? By bringing the ground conductors
through the wall of the building and into the panel and there connecting
them to the existing ground bus? Or . . . ?