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Joined: Jul 2002
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Greg,
I used to do a lot of work in wiring dairy sheds (parlors I believe you guys call them over there).
Cows cause a real mess if there is ANY stray voltage due to poor earthing.
The standard used to be that you had to have a maximum earth resistance of 0.05 ohms at any point to earth.
Everything was multiply bonded, it was a nightmare, I don't miss them days.
Although it did make me buy one of them Fluke multi-function testers, best (lots of) money I ever spent. laugh

Last edited by Trumpy; 12/01/22 06:55 AM. Reason: Missing word
Joined: May 2021
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E
New Member
Grounding together with the leakage relay in an electrical installation is our basic protection. A good ground such as the foundation (ground) absorbs all the electrical leakages (electrical currents) that will occur in an installation, from a fault. In short, the role of grounding is to transfer to the ground (the earth), the dangerous electrical leaks that can cause electric shocks to humans. The installation of foundation grounding imposes a prefectural basis not only in Patras but throughout Greece, in all new buildings.


ΗΛΕΚΤΡΟΛΟΓΙΚΕΣ ΕΡΓΑΣΙΕΣ ΠΑΝΤΟΣ ΤΥΠΟΥ
Joined: Jan 2005
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Cat Servant
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This tool looks interesting — it lets your demo hammer grip the rod closer to the ground. Much less of your impact is lost to the rod wobbling, and no need to start from a ladder.
Has anyone tried it?

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F0D34670-E083-4AC0-94AE-D01487784FFE.png
Last edited by renosteinke; 04/04/23 02:42 PM. Reason: Add photo
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Cat Servant
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I was really hoping someone had tried that rod driving accessory. For this job I had bought one -- and promptly lost it frown No matter; both rods went into clay readily using an SDS-Max demo hammer.

Now: for the ground wire ("GEC", or Grounding Electrode Conductor). It has been my practice to run a #4 solid wire in EMT to the first ground rod. Since this particular location would have made the pipe a trip hazard and annoying to the gardener, I chose to use heavier pipe (RMC).

Starting at the panel, I used an intersystem grounding bonding device sold by Ideal. This device connected my pipe to the panel and completely protected the wire. The Phillips screw, when tightened, bonds the wire to the inside of the block. This is the only intersystem bonding device I've seen of which I approve. (first picture)

(I'll post additional pictures separately. I wish to encourage discussion on each detail of this job).

Attached Images
Intersystem 1.JPG
Last edited by renosteinke; 04/20/23 02:53 PM.
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Cat Servant
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As for the EGC, and the manner of its protection: Growing up in the Sixties, I saw the grounding practices change quite a bit.
Before 1960, IF there was a ground at all, it was a light gauge wire that was tied off to a water pipe.
Once ground rods became typical, I often saw an unprotected wire go to a rod that was often either inside the crawlspace or punched through the basement floor.
In the suburbs, with the surge in "ranch" style tract homes, requirements quickly evolved. First the lawn mower, then the weed whacker were blamed for damaging the wire. This led to requiring (first) solid wire, then upping the size to #4, then requiring the wire to be in pipe. By 1970 the use of EMT was universal -- the use of PVC, even today, is greatly discouraged. (Think: Chicago)
In Arkansas today, a typical EGC will be #6 stranded (usually green -- forget the NEC!) in PVC. About a foot fron the panel the PVC will be separated and a surface-mounted intersystem bonding block inserted.

For this job I chose RMC, bent to protect the wi
re until it was well underground. I protected the pipe from corrosion with heavy vinyl "pipe wrap tape".

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Pipe wrap 1.JPG
Joined: Jan 2005
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Cat Servant
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Now, about bonding the GEC to the conduit . . .
Some have expressed fears that should the GEC not be connected to the conduit at BOTH ends, a "choke" can occur that will reduce the current carrying ability of the wire. Personally, I think this is a non-issue. I defy you to run a bare #4 wire through bent pipe without the wire contacting the pipe at several points.

None the less, a connector is made for this task. I've used them several times, and I've attached a catalog drawing of one. Alas, electrical supply houses here have exactly zero interest in obtaining them. Indeed, they look at me as though I'm out of my mind for wanting such a thing. ("I've been in this business forty years and never had anyone ask ...")

Time waits for no one, so I had to improvise. I've attached a picture; combine a rigid coupling with an NM 2-screw connector and you get something that just might work. Picture attached.

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GEC Sketch.png GEC Bond 1.JPG
Joined: Jul 2004
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That must be a northern thing. I got one here with no problem and as an inspector I saw them all the time. As for the Romex connector, I would cite 110.3(B) and tell you to come up with a better solution. They are not listed for direct burial and that strap will rust out in less than a year.


Greg Fretwell
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How long do you think those steel ground screws will last in the weather? Do they sell a 3r enclosure for that ground block? I like the idea but the weather protection seems weak. The blocks I see here usually have a plastic box with a cover that snaps shut. If they don't use a little duct seal the wasps love them tho.


Greg Fretwell
Joined: Apr 2002
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Reno,
The protection of the GEC up here (resi) is PVC for 'physical protection and 'neatness'. Comm jobs are usually direct burial under the concrete and the rods are 'flush' to grade in the adjacent soil. The terminations of the GEC to the rods is down 6"+ from the top of the rod, so the conductor is 'safe'.

The larger comm jobs usually are spec'd for 10' rods in triad, with inspection holes at each rod for testing purposes, so damage is not a question.

As to the 250.94 blok, I like the design, but as Greg said, corrosion issues; however, at time of inspection it should NOT be an issue. (Possible firestorm comment)

The 2 screw NM connector is and has been an 'issue' item around these parts for many, many years. Personally, I can't see it for choking purposes on metalic conduits with GEC conductors. (Inside)

And FWIW, you really do address the details.


John
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Interesting you mentioned "inspection". EC&M Magazine has a grounding article on the cover. They go through and list all the legal connectors you can use for grounding and Romex connectors do not make the list. 110.3(B) seems to be enough but you could go to the language cited in the article if you want more.
OTOH if someone did come up with bronze or stainless strap and screws for that zinc NM connector body I might chuckle and walk by. I also might agree with Reno that a short sleeve on a direct buried copper wire won't be much of a choke anyway and just ignore the whole thing.

t really doesn't come up here either. They like RNC.
I used the hubs and EMT at my house, just because Home Depot had the part.


Greg Fretwell
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