Earth Ground--Is This Right?

[Winky Dink]

I finally made the effort to establish a proper earth ground for my second-floor workbench. Of course I have no metal pipes and the main electrical ground for the house is 100 feet from the bench.

I put in an 8-foot copper-plated steel rod (Zareba sectional ground rod for electric fences) which leaves 15 feet to reach the bench upstairs. For the connection, I used standard TV video coaxial cable with 18 awg copper coated solid wire as the conductor and foil/braided steel as the RF shield. Does this sound right so far? With the steel braid connected to the ground it seems to work well for my recently-completed Atwater Kent Model 30.



I've based this setup on the shielded connections I've seen within radio chassis and on trial and error. Any suggestions on correcting or improving what I've done?

As always, I'm very grateful for any advice.

[N2IXK]

Per the National Electrical Code, that rod really needs to be bonded to the rest of the building electrical grounds. Depending on soil conditions, there could be an appreciable difference in potential between rods driven in different locations on a lot.

An "lone rod" type ground can cause problems if used to ground sensitive electronics, as well.

[Winky Dink]

I appreciate the advice. In fact, the directions for grounding an electric fence require three of these rods.

In this case, however, is there really a safety issue? The ground is only used intermittently for RF signals. Otherwise, the set would not be grounded at all, and the shock hazard is addressed with an isolation transformer.

Please understand that I am not questioning your advice, but need to know, in this case, if there is a safety concern.

[NoPegs]

Originally Posted by Winky Dink

I appreciate the advice. In fact, the directions for grounding an electric fence require three of these rods.

In this case, however, is there really a safety issue? The ground is only used intermittently for RF signals. Otherwise, the set would not be grounded at all, and the shock hazard is addressed with an isolation transformer.

Please understand that I am not questioning your advice, but need to know, in this case, if there is a safety concern.

The use you're describing would classify your rod as a proper "Technical Earth." As mentioned just be aware that there is potential for current to flow in the event that "Safety Ground" is connected to your "Technical Earth."

[Winky Dink]

Thanks, guys. I'm glad I asked, because I haven't got a good handle on this. So I'll have an old-fashioned telephone discussion with K3KU, my electronic guru, and proceed with due caution.

[JBL GUY]

Keep in mind that a violation of the NEC may be enough of a reason for an insurance company to deny a claim for damage do to an unwanted electrical event, power surge, lightning strike and so on.

It is all about risk management. Even with the use of an isolation transformer there are still failure modes, however rare, that can pose a danger and potential issues with insurance.

The NEC spells out the correct method, it is up to you to decide how you do your implantation.

[Username1]

I don't know what the NEC says, but I use to do pumps for irrigation systems with
a guy who knew the stuff inside out. And there is a way to set up a ground, locally.
And what I mean by locally, is that yes you may need 3 rods, and it depends on your
soil type, and drainage, moisture. So please be sure you are applying the correct
method for your soil.... And I think it may be smart to at least measure the potential
difference between your new ground, and the established electrical ground used for
your electric supply.... It may be smart to connect them together.... But be aware
that lightning strike protection may require running the ground wire from your bench
to the ground rod with larger wire, and at a distance, and specific route to the rod(s).

.

[Electronic M]

"Earth Ground--Is This Right?" Nope. What you need to do is get a loooong connect wire and on a bright night shoot that rod from a gun that is being fired from a cannon that is being launched from a catapult and establish a good old fashioned MOON GROUND....It'll take some practice to hit the moon, and the wire constantly moving/tangling across the globe gets annoying, but once your rod is planted in the moon you will get ALL the stations.

Seriously though, nice work on that ground rod. Even when I had a long wire I never got round to making a ground. I want to put up a long wire, but we have had a tree leaning on the one I want to anchor the antenna on, and it don't look like a darn thing is going to be done about it for some time....