Harold E. Johnson wrote:
Interesting. Here in Florida, the lightning capital of the continental
US, the ordinary electrical service grounding mechanism is *only* via
bonding to the metal in the foundation. New house construction will not
pass inspection without such a connection unless other more complex
arrangements are fashioned. There are typically no driven ground rods, and
water pipes are usually non-conductive. (The NEC no longer allows water
pipes to serve as the sole ground in any case.)

73,
Gene
W4SZ

Must be a recent rules change Gene. I used to manufacture and sell an
instrument to the power companies in FL, a meter that they would connect
between one 120 Volt leg of the service drop and the residential ground rod,
and drive the rod for a 25 Ohm ground. Typically, if they were installing
pad mount transformers for underground service, they would install another
ground rod there.

The Withlacoochee Co-Op, which serviced some of the highest sand dunes in
FL, would often drive 60 feet of ground rod to reach the required
conductance.

W4ZCB



I don't know when the change was made. I discovered this rule when our
house was being built in 2003. I noticed that there were no ground rods,
and I started asking questions and looking into the code. Florida
follows the NEC without exception. No modifications or local electrical
codes are allowed. Of course the AHJ can override almost anything if he
decides to.

As you know, the electrical utilities generally are not bound by the NEC
or other codes. They follow their own rules. Also, there are a lot of
preexisting cases where the foundation steel is not connected to the
outside of the concrete. Ground rods must be used. In those cases your
ground-checker instrument would still be useful.

73,
Gene
W4SZ

I don't know when the change was made. I discovered this rule when our
house was being built in 2003. I noticed that there were no ground rods,
and I started asking questions and looking into the code. Florida follows
the NEC without exception. No modifications or local electrical codes are
allowed. Of course the AHJ can override almost anything if he decides to.

As you know, the electrical utilities generally are not bound by the NEC
or other codes. They follow their own rules. Also, there are a lot of
preexisting cases where the foundation steel is not connected to the
outside of the concrete. Ground rods must be used. In those cases your
ground-checker instrument would still be useful.

73,
Gene
W4SZ

I should have put a smiley face somewhere in the same zip code with the
"recent" Gene. My experience ended in 1986 when I retired. Back then, (And
for a good many years before) it was known as a "NEMA" Ground and 25 Ohms
was the value.

I had a country home near Brooksville, FL, with some acreage and 5 towers
(Tallest 160 feet) for a little contesting. Being there only on weekends, it
WAS a fairly high maintenance property. Hardly a time when I went there that
there was not evidence of some lightning damage, even with considerable
effort to minimize it. Before cell phones, I was close to being the highest
thing in the county.

Regards
W4ZCB

Harold E. Johnson wrote:
I don't know when the change was made. I discovered this rule when our
house was being built in 2003. I noticed that there were no ground rods,
and I started asking questions and looking into the code. Florida follows
the NEC without exception. No modifications or local electrical codes are
allowed. Of course the AHJ can override almost anything if he decides to.

As you know, the electrical utilities generally are not bound by the NEC
or other codes. They follow their own rules. Also, there are a lot of
preexisting cases where the foundation steel is not connected to the
outside of the concrete. Ground rods must be used. In those cases your
ground-checker instrument would still be useful.

73,
Gene
W4SZ


I should have put a smiley face somewhere in the same zip code with the
"recent" Gene. My experience ended in 1986 when I retired. Back then, (And
for a good many years before) it was known as a "NEMA" Ground and 25 Ohms
was the value.

I had a country home near Brooksville, FL, with some acreage and 5 towers
(Tallest 160 feet) for a little contesting. Being there only on weekends, it
WAS a fairly high maintenance property. Hardly a time when I went there that
there was not evidence of some lightning damage, even with considerable
effort to minimize it. Before cell phones, I was close to being the highest
thing in the county.

Regards
W4ZCB


Here of course we are talking about a safety ground connection. But for
RF grounding you could you a counterpoise to your antenna. Just a wire
array under the antenna system as used in the western desert in WW2.
That would help to make the performance of your antennas more
predictable at any rate.
Here in NZ I am having ground troubles in a new subdivision. On a heavy
clay soil with a reasonably heavy annual rainfall ~50 inches/year.
The utility company appears to have very badly balanced the 3 phase
underground power phases and it looks like we have quite a high current
circulating between local grounds on our mains earth neutral system.
Result, a lot of rf noise coming up the ground connection and even being
radiated into antennas on local AM radio and ham equipment. They have
been working on the problem but after 8 months we still have an s6/7
noise level across the HF bands.
We are still on their case however.
73's cliff wright ZL1BDA.