Ground rod - angle of installation

infinity

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Staff member
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New Jersey
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Journeyman Electrician
So how did he check them? When you have a bolt tightened it takes more torque than it was originally tightened to To break it loose. Once it turns its overtorqued and you should start all over.

It’s really not important, but TECHNICALLY he was doing it wrong...
Why would it need to break loose? The torque wrench will click to indicate that it's at least as tight as the torque setting of the wrench without moving the bolt. If it's not tight enough the bolt will turn.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
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Henrico County, VA
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Electrical Contractor
Torque is normally supposed to be set while the bolt or (preferably) the nut is turning. If you go back to tighten a torqued fastener more, it will take a bit of extra force to break the static friction, then ease back to real installing torque as it's turning.

Thus, checking by trying to turn it again/more may show proper torque was attained while it wasn't (presuming it was not torqued fully the first time). I've used a beam-type torque wrenches over the years, and this behavior shows itself whereas a click-type won't.
 
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kwired

Electron manager
Location
NE Nebraska
Why would it need to break loose? The torque wrench will click to indicate that it's at least as tight as the torque setting of the wrench without moving the bolt. If it's not tight enough the bolt will turn.
Overtightening is an improper installation as well so if it doesn't turn before wrench clicks how do you know it isn't too tight?

only way to check would be to loosen first then re-tighten to proper torque setting.

I'd guess that at some point overtightening possibly can do irreversible damage in many cases.
 

FionaZuppa

Senior Member
Location
AZ
Well since the main general rule is to drive it vertically why wouldn't that be the reference point for determining any optional angle?

Otherwise if horizontal were the reference then they would have to state no less than 45 deg instead of no more than.
Horizontal is the actual reference, because that's the exact plane you are driving the rod into, there is no other plane, it's XY. My point is, there's no reason to add an additional reference of "vertical", it's simply not needed. It's not wrong, but simply not needed. When possible, it's always better to simplify the grammar.
 

FionaZuppa

Senior Member
Location
AZ
My point was, there was a reason that the NEC includes the word vertical. I don't believe the NEC provides guidance on the relationship of the ditch with the slope of the surface.
What's the reason? The only reason I see is so the words "not more than 45deg" can be used and "vertical" is the reference 0deg. One could then say the ground plane (XY) is at 90deg, but that really makes no sense in terms of convention, or even the fact that the rod is driven into the ground plane. The word "vertical" is also a compound reference of two planes XZ and YZ, as "vertical" must then be parallel to both of those planes, which just so happens to be exactly 90deg from the XY plane.
 

FionaZuppa

Senior Member
Location
AZ
Torque checking goes back to the other thread where it mentions MH's "how to check" inspector doc. The check is to set the tq tool to 90% of the spec torq, if it clicks at 90% it's good.

The reason why a click at 100% on a already tight nut/bolt is not an accurate check is simple, the existing torq could still be under 100% and because of static friction the torq tool setting of 100% will click prior to the spec torq #. To check an already set nut/bolt you would need to know what that static friction is and then add that to 100% of spec torq.

Hence why it was said many times, setting torq requires the item to be set in kinematic process (aka "moving").
 

FionaZuppa

Senior Member
Location
AZ
Yes, the NEC is simply defining their reference, why do you feel this makes the NEC 'oddly written'. The NEC wording addresses the situations when the ground plane is slanted.
Because you don't need to add words to describe the same thing, thus simplifying the verbiage. The NEC simply added words to make what they were saying work. As I mentioned, the word "vertical" if a referece to the ground plane XY, and, it also means "parallel to two planes XZ and YZ", which basically just complicates the meaning of "vertical".
 

NewtonLaw

Senior Member
I wasn't looking for anyone to agree with me on this but I see that many of you stated "if you hit rock". I don't know any other way to explain this other than my work is primarily in the mountains. Every time you stick a shovel in the ground up here you hit a field stone. There is also a large amount of sedimentary rock in the area. That said, when an EI inspects a job and 99.99% of that job is exceptional why pick something like a ground rod angle to put a red sticker on a panel, causing your customer to think you did something so severe and dangerous that a red sticker was put on the panel and above all your $$$ gets hung up until you correct the violation.

Regarding the 45 degree angle, where did the NEC CMP come up with that as a solution ? What difference would it make if the angle was 90, 45, 35, 25, etc. Rock is rock. Changing the angle does not guarantee that the rod will be driven properly into the earth anyway. Just out of curiosity, do you think the EI came out to the job with a protractor ?

I'm just repeating myself here, I'm looking for solutions or remedies and not the FACT that I drove the rod incorrectly. Thanks you all for your replies.
The NEC 2017 limits you to the 45 degree angle or horizontal installations where the electrode is buried 2.5’ down. The spirit of the code wants you to obtain a minimum resistance to ground of 25 ohms. I know this is hard to achieve in a rocky environment and I find it laughable that the code then states the solution as the addition of another set of electrodes and yet says nothing about what to do if you can not get the 25 ohms even then. Perhaps the EI is looking at that as opposed to the 45 degree angle. Do you know for sure it is because of the angle of installation? Also, if you can demonstrate that you have 25 ohms or less, perhaps that would be acceptable?
 

jim dungar

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Location
Wisconsin
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Because you don't need to add words to describe the same thing, thus simplifying the verbiage. The NEC simply added words to make what they were saying work. As I mentioned, the word "vertical" if a referece to the ground plane XY, and, it also means "parallel to two planes XZ and YZ", which basically just complicates the meaning of "vertical".
Your logic is not straight forward, it does not address the issue of a slanted plane. The NEC does not want the ground rod driven perpendicular to the surface, it wants it vertical.
 

FionaZuppa

Senior Member
Location
AZ
Your logic is not straight forward, it does not address the issue of a slanted plane. The NEC does not want the ground rod driven perpendicular to the surface, it wants it vertical.
??
Ah, it's still the same thing. In spherical coord system a radial line can be the "vertical", but that line is perpendicular to all points that define the XY plane (the normal ground plane). This description thus orienats the XY plane so that the intersection of the radial to XY also forces XY to be tangential to the sphere Earth. Thus, it still properly addresses your slanted hillside scenario.
 

infinity

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New Jersey
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Journeyman Electrician
Overtightening is an improper installation as well so if it doesn't turn before wrench clicks how do you know it isn't too tight?

only way to check would be to loosen first then re-tighten to proper torque setting.

I'd guess that at some point overtightening possibly can do irreversible damage in many cases.
I don't think that an inspector is checking for over-tightening, if they are then we should just leave the connections loose and let him torque them down. ;)

The idea of losening and re-tightneing connections for an inspection is just not practical.
 

FionaZuppa

Senior Member
Location
AZ
Seriously, do you really consider the use of spherical coordinates to be less odd than the use of the word vertical?
I do not, but how else would you describe "vertical" in terms of any coord system. I used two of them to drive my point home (no pun intended).

How would you describe "vertical"? Maybe if I had a weight hanging on a string, that chord is "vertical"?, which also happens to be a radial, and, also parallel to XZ and YZ at the same time.

If I was on a hillside that was 44deg from "vertical" and I used the rule to drive rod in at 45 degree, I would be 1deg into the dirt? Hmmm, that makes no sense.
 

kwired

Electron manager
Location
NE Nebraska
Many
??
Ah, it's still the same thing. In spherical coord system a radial line can be the "vertical", but that line is perpendicular to all points that define the XY plane (the normal ground plane). This description thus orienats the XY plane so that the intersection of the radial to XY also forces XY to be tangential to the sphere Earth. Thus, it still properly addresses your slanted hillside scenario.
NEC users, especially the ones that are driving ground rods often, don't necessarily have degrees that involved taking much for advanced mathematics courses. What is so complicated about "no more than 45 degrees (from vertical) if vertical is the general requirement?
 

kwired

Electron manager
Location
NE Nebraska
I agr
I don't think that an inspector is checking for over-tightening, if they are then we should just leave the connections loose and let him torque them down. ;)

The idea of losening and re-tightneing connections for an inspection is just not practical.
I agree not practical. Also believe if inspector truly is concerned about proper torque, only way to know is to witness actual tightening. Checking after the fact proves nothing. You can come back some time later to many terminations with torque wrench on same setting and likely can turn the set screw some before the wrench clicks. That don't mean you were wrong the first time. Proper tightening is to stop when the wrench says you are there.
 

jim dungar

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Location
Wisconsin
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Retired Engineer
If I was on a hillside that was 44deg from "vertical" and I used the rule to drive rod in at 45 degree, I would be 1deg into the dirt? Hmmm, that makes no sense.
In construction trades, the words level and vertical or plumb are very common, and rarely need further explanation.
Yes, the top of the rod would be only 1 deg into the dirt, but the bottom of the rod would not. Maybe we could argue about the requirement to use a 10' rod in this case.

I believe the NEC ground rod requirements seem to be based more on tradition rather than science.
 
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FionaZuppa

Senior Member
Location
AZ
In construction trades, the words level and vertical or plumb are very common, and rarely need further explanation.
Yes, the top of the rod would be only 1 deg into the dirt, but the bottom of the rod would not. Maybe we could argue about the requirement to use a 10' rod in this case.

I believe the NEC ground rod requirements seem to be based more on tradition rather than science.
I did work construction for some years, we never used the word "vertical", it was always "plumb" and "level". We used 2/4/8ft levels to determine both "level" and "plumb", and then with bubble levels could get a sense of pitch depending on what lines were on the bubble. I never saw a digital inclinometer level in that trade, probably too expensive at the time.

I was just noting the NEC seems to throw in extra words when it's technically not needed.
 
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