suspended ground rod

I am doing work in Bermuda and the local contractor is telling us that a ground rod connected to a grounding electrode conductor and suspended in an 8" x 10' bored well/hole is how they are required to install ground rods?
The attached file is a copy of the installation instructions?
I have never seen the installation of ground rods suspended in salt water, and of course I have not found anything in the NEC that seems to allow such an installation?
Has anyone seen this? View attachment Gnd Well Detail detail (1).pdf
 

kwired

Electron manager
Location
NE Nebraska
I am doing work in Bermuda and the local contractor is telling us that a ground rod connected to a grounding electrode conductor and suspended in an 8" x 10' bored well/hole is how they are required to install ground rods?
The attached file is a copy of the installation instructions?
I have never seen the installation of ground rods suspended in salt water, and of course I have not found anything in the NEC that seems to allow such an installation?
Has anyone seen this? View attachment 14673
Seems like having the PVC sleeve for a well casing would create a capacitor out of it. Might still be a better electrode then a rod driven in desert sand though, as long as the well never goes dry.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
I am doing work in Bermuda and the local contractor is telling us that a ground rod connected to a grounding electrode conductor and suspended in an 8" x 10' bored well/hole is how they are required to install ground rods?
The attached file is a copy of the installation instructions?
I have never seen the installation of ground rods suspended in salt water, and of course I have not found anything in the NEC that seems to allow such an installation?
Has anyone seen this? View attachment 14673
I doubt you will find that the code prohibits such a thing. It just would not count as a GE in the US.

Maybe this is a floating building of some sort.

Personally, I would be real suspicious of installing a copper wire in salt water.
 

mwm1752

Senior Member
Location
Aspen, Colo
where would you find a 2" dia x 10' cu ground rod -- 4/0 cu for the conductor size? thats alot of pennies (pre 1980 of course)
 
where would you find a 2" dia x 10' cu ground rod -- 4/0 cu for the conductor size? thats alot of pennies (pre 1980 of course)
That must weigh quite a bit. Is it just supposed to hang off the 4/0 conductor? Notice the drawing shows the bottom of the rod 3' above the bottom of the tube.

I am also interested in how one would get the 4/0 into the 1" PVC coming out of the side of the tube.
 

cuba_pete

Senior Member
Location
Washington State
I have a similar system

I have a similar system

I see 20 callouts with none aligning with the provided drawing. it's kind of hard to make a call here with a very small part of the overall picture.

Is the drawing for the grounding electrode or "ground bus in computer room" (supplemental)?

The drawing does not necessarily infer that this is dangling in water. I have several ground wells in my facility which are very similar. The water table intrudes a lot from time to time and in order to prevent shifting of the soil which would cover the top of the ground rods (rendering them not visible to inspection) they are driven deep into the soil, well into the water table. Your draftsman needs to be more specific to the engineer's requirements. I would expect to see some type of hatching interior to the PVC well to indicate fill.

The low water level in your example would ensure that the ground rod met resistance requirements reliably.

As far as the "mechanically fastened" part, I would change that to a brazed. Again, that is how all of mine are. I have two fields (5 and 7 rods each) which are installed in similar fashion.
 

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tom baker

First Chief Moderator
Staff member
There is a company that sells a similar type grounding electrode made of copper tube, I can't remember the name of the company, they were used on a pump station, 480V supply.
I don't see the advantage for the typical electrical service, but for telecom sites with lightning, that could be an application
 

Fulthrotl

~~Please excuse the mess. Sig under construction~~
I am doing work in Bermuda and the local contractor is telling us that a ground rod connected to a grounding electrode conductor and suspended in an 8" x 10' bored well/hole is how they are required to install ground rods?
The attached file is a copy of the installation instructions?
I have never seen the installation of ground rods suspended in salt water, and of course I have not found anything in the NEC that seems to allow such an installation?
Has anyone seen this? View attachment 14673
i've seen a forestry lookout station that had extensive lighting rod systems
have something similar, and the lookout would pour a pail of water in to
soak the ground rod before a lightning storm.

never a service ground, tho....
 
This will act as a pipe bomb when lightning strikes -- the mega watts energy might vaporize the small liquid in a sealed chamber in a short time, creates an explosion propelling the rod straight up to the moon.
 
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