"Jim Miller" wrote
Hi Jack

I missed something in the above: you said an 8ft rod driven 10ft into
the ground? Does that mean the top of the rod is buried 2ft?

Then driving such a rod every 2x rod depth feet would mean one every
20ft vs every 16ft?

What would be the recommended connecting conductor between all the
points? Big honking cable or copper strapping?

I haven't purchased the ICE unit yet until I had gotten some feedback
so making that change is no problem.

So you would suggest two ICE units? One at the antenna base and another
at the station ground?

BTW, I'm wondering if any installation has ever met the codes you cited
other than a dedicated broadcast transmitting facility. Certainly would
be the exceptional (1%) residence in my experience.

thanks for your help!

jtm


Hi Jim, I was quoting from the fire and electrical codes regarding grounding
electrodes, and yes they mean buried 2' beneath ground surface to reach a
total depth of 10'. Use the length of the rod in the ground, not rod depth
when determining spacing. That confusing aspect came about when 10' rods
were going to be maintained as the minimum length allowed, and contractors
screamed they could not obtain them (cheaply). So the 8' rod buried to a
depth of 10' was born.

Use 16' as the spacing between buried 8' rods.

Recommend minimum #4 copper or heavier for the service entrance to station
bonding connector. It does not have to be continuous if intermittent-spaced
ground rods are used. If you figure out some way to efficiently trench for
6" deep 26ga copper strap, please let me know - that would be ideal. Strap
is also difficult to bond to ground rods, and generally too thin for
exothermal (cadweld) connections.

As for using two coax lightning arrestors, that might rarely if ever be
specified. Normally the shield-grounding along the tower and at station
entrance is sufficient that one arrestor either on the master ground bus or
right outside at the 1st ground rod would suffice. But you are trying to
protect your external tuner (let us know how that works out ) and might
permit some voltages the receiver front-end doesn't like, should they be
induced or shorted from shield-to-conductor along the feedline path.

As far as meeting electrical codes and fire standards for grounding systems,
there is no way around that in my opinion. If your home is going to be
protected from loss by insurance, then you either need to meet all codes and
standards, or else somehow demonstrate that you isolate all systems safely
before the risk of loss occurs. Personally I don't know how most amateur
operators ever collect for lightning damage, since examination by forensic
(fire) investigators could show failure to meet code and/or best industry
practices in most cases. Yes, you are a "broadcast station" wrt lightning,
and in an area subject to it, should take appropriate measures to either
always be isolated before the risk occurs, or withstand the risk by plan and
design. Proper isolation is not just tossing the feedline out the window as
so many unfortunately believe. Considering the risk involved if proper
isolation is not followed, protecting the whole property seems like a better
plan to me.

73,
Jack

Hi Jack

Just got back from HomeDepot where they had 5/8"x8' copper rod and
bronze clamps as well as #2 copper wire. I'll use two bronze clamps on
each so I can daisy chain the #2. I can put one on the corner of the
house and two more along the way to the service ground. That will make
four including the station ground around the house and one out at the
antenna tuner.

Thanks for your help

jtm (risk averse...)

On Wed, 2 Mar 2005 13:23:25 -0500, "Jack Painter"
wrote:





Hi Jim, I was quoting from the fire and electrical codes regarding grounding
electrodes, and yes they mean buried 2' beneath ground surface to reach a
total depth of 10'. Use the length of the rod in the ground, not rod depth
when determining spacing. That confusing aspect came about when 10' rods
were going to be maintained as the minimum length allowed, and contractors
screamed they could not obtain them (cheaply). So the 8' rod buried to a
depth of 10' was born.

Jack, isn't this getting a little over-the-top? I have to dig a 2
foot hole, get an 8 foot rod totally buried in that hole -- and then
what, to bond different rods together, dig a 2 foot trench from rod to
rod to bond them together with strapping?

And what about all the corrosion on the buried rods and strapping?

Who does this sort of stuff !! ??

I understand you're quoting from codes, but does anyone "residential"
really do this stuff?

bob
kj5qwg

"Bob Miller" wrote
On Wed, 2 Mar 2005 13:23:25 -0500, "Jack Painter"
wrote:


Hi Jim, I was quoting from the fire and electrical codes regarding
grounding
electrodes, and yes they mean buried 2' beneath ground surface to reach a
total depth of 10'. Use the length of the rod in the ground, not rod
depth
when determining spacing. That confusing aspect came about when 10' rods
were going to be maintained as the minimum length allowed, and
contractors
screamed they could not obtain them (cheaply). So the 8' rod buried to a
depth of 10' was born.

Jack, isn't this getting a little over-the-top? I have to dig a 2
foot hole, get an 8 foot rod totally buried in that hole -- and then
what, to bond different rods together, dig a 2 foot trench from rod to
rod to bond them together with strapping?

And what about all the corrosion on the buried rods and strapping?

Who does this sort of stuff !! ??

I understand you're quoting from codes, but does anyone "residential"
really do this stuff?

bob
kj5qwg

Hi Bob, you're right few people follow NEC code to any degree unless an
inspector is going to follow. And I hope I pointed out a couple examples
where code was changed or written because of convenience, not science (the
2' below grade level and non-continuous requirement). So in some cases
following code is not the best practice (it needs to be exceeded) and in
other cases is just not practical or possible. You be your own judge there.
Anyone who follows the topic knows why the rules are there, and that in the
case of a casualty, an investigation may assign blame whether code was
followed or not, but certainly if it was not.

The knowledge gained and effort made to protect property is certainly more
important than splitting hairs about code that is a moot point for most.

73,

Jack Painter
Virginia Beach, Virginia