# What's better than one 8 foot ground rod?



## RePhase277 (Feb 5, 2008)

I make that gamble based on the POCO spec. Chances are, if the POCO spec sheet only shows one rod, the inspector is only looking for one as well. Sometimes.

The code doesn't specify how the 25 ohms is to be verified. Stick a hot wire to the rod and use Ohm's Law to calculate the resistance. It's as valid as any other means.


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## just the cowboy (Sep 4, 2013)

*Salt water*

When in the city EC's poured saltwater around the ground rod, they passed.


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## Southeast Power (Jan 18, 2009)

RePhase277 said:


> I make that gamble based on the POCO spec. Chances are, if the POCO spec sheet only shows one rod, the inspector is only looking for one as well. Sometimes.
> 
> The code doesn't specify how the 25 ohms is to be verified. Stick a hot wire to the rod and use Ohm's Law to calculate the resistance. It's as valid as any other means.


If you can blow a 5 amp fuse, phase to ground rod, that should do it.


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## Big John (May 23, 2010)

I keep thinking I should submit a proposal to remove that dumbass 25 ohm rule.

Why on earth is one electrode required to have a 25 ohm resistance, but as long as you have two electrodes you can have a 10,000,000 ohm resistance and that's fine?

I seem to remember this rule is some BS holdover from old turn-of-the-century telephone systems and has no actual bearing on how modern electrical services operate.

1 electrode is perfectly fine. Prove me wrong.


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## HackWork (Oct 2, 2009)

I agree with you John. But this rule is just one of many stupid and arbitrary rules in the NEC that we will probably never see go away.


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## drsparky (Nov 13, 2008)

A gold plated 8' ground rod would probably test good, solid gold would be even better. Hard part is up selling the idea to the customer. :brows:


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## Bird dog (Oct 27, 2015)

Big John said:


> I keep thinking I should submit a proposal to remove that dumbass 25 ohm rule.


I was reading a MH forum thread on this & someone already did but it got turned down.


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## Big John (May 23, 2010)

Bird dog said:


> I was reading a MH forum thread on this & someone already did but it got turned down.


You have a link? I'd like to read the justification for rejecting an existing rule which appears to have no technical justification.


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## socket2ya (Oct 27, 2016)

drsparky said:


> A gold plated 8' ground rod would probably test good, solid gold would be even better. Hard part is up selling the idea to the customer. :brows:


If you were to use a sledge to pound a gold ground rod, I envision there being quite a mushroom effect on the top of the rod. No sliding the acorn over that


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## socket2ya (Oct 27, 2016)

I've heard that Silver is a better conductor than gold. Is that true


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## fisstech (Feb 2, 2013)

dig a 3 foot hole and put a ground plate in.


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## Bird dog (Oct 27, 2015)

Big John said:


> You have a link? I'd like to read the justification for rejecting an existing rule which appears to have no technical justification.


No real justification, but, I only scanned briefly.

http://forums.mikeholt.com/showthread.php?t=119107


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## HackWork (Oct 2, 2009)

socket2ya said:


> I've heard that Silver is a better conductor than gold. Is that true


Yes, but gold is better for connections because it doesn't tarnish like silver.


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## HackWork (Oct 2, 2009)

fisstech said:


> dig a 3 foot hole and put a ground plate in.


Who the hell wants to dig a 3' hole??!!?! I don't want to dig a 3" deep trench to fit a #6 wire inside of, I'm sure as hell not digging a 3' hole!


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## Southeast Power (Jan 18, 2009)

HackWork said:


> Yes, but gold is better for connections because it doesn't tarnish like silver.


Silver sulphide(tarnish) is conductive silver compound.


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## Southeast Power (Jan 18, 2009)

socket2ya said:


> If you were to use a sledge to pound a gold ground rod, I envision there being quite a mushroom effect on the top of the rod. No sliding the acorn over that


I think it would disappear before the first strike.


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## daveEM (Nov 18, 2012)

I've put a couple of 10 footers in 10 feet apart. Right next to the building. 

3/4 pvc LB and a bit of pvc conduit at each one then into the building. Drill across and connect them.

Looks ok on a garage as you would do this on the wall by the fence plus a foot off the ground isn't too ugly. Not sure what it would look like in your case.


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## Southeast Power (Jan 18, 2009)

HackWork said:


> I agree with you John. But this rule is just one of many stupid and arbitrary rules in the NEC that we will probably never see go away.


 George Soros?


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## RePhase277 (Feb 5, 2008)

The 25 ohm rule, and the additional electrode if you can't achieve 25 ohms, has been in the code for as long as the secondary has been required to be grounded. They're both in my 1917 Hawkins Electrical Guides.

I haven't been able to locate how or where the 25 ohms came about. Looks arbitrary. 100 million volts doesn't care if it's 25 ohms or 2500 ohms.


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## telsa (May 22, 2015)

HackWork said:


> Two 4 footers of course. But that still requires me to dig a trench to the second rod, which sucks.
> 
> Has anyone ever just driven 1 ground rod and then made the gamble on whether the inspector would be willing to wait around to test it? I'm thinking about trying that... 25 ohms bitches!


A Ufer. :thumbsup:


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## MechanicalDVR (Dec 29, 2007)

HackWork said:


> Who the hell wants to dig a 3' hole??!!?! I don't want to dig a 3" deep trench to fit a #6 wire inside of, I'm sure as hell not digging a 3' hole!


Go to Home Depot and hire a couple parking lot laborers to dig, get em before they get deported!


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## HackWork (Oct 2, 2009)

telsa said:


> A Ufer. :thumbsup:


So I should knock the house down and rebuild the foundation every time someone wants a service upgrade? Cause that would sure be easier than digging a trench to the second ground rod...


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## nrp3 (Jan 24, 2009)

Must...sell....more...ground rods....


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## HackWork (Oct 2, 2009)

nrp3 said:


> Must...sell....more...ground rods....


That's why I only buy one. Cut it in half with a bandsaw, make the cut on a 45 degree angle to get a nice point on each end.


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## HackWork (Oct 2, 2009)

MechanicalDVR said:


> Go to Home Depot and hire a couple parking lot laborers to dig, get em before they get deported!


It's not even that. I will have a guy doing the panel change so I may do the ground rods myself while he's working on the panel or I may have him do them if I get lazy. But either way, I just hate having to spend the time and mess up the landscape digging to the second rod. It's just my personal pet peeve.


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## MechanicalDVR (Dec 29, 2007)

HackWork said:


> It's not even that. I will have a guy doing the panel change so I may do the ground rods myself while he's working on the panel or I may have him do them if I get lazy. But either way, I just hate having to spend the time and mess up the landscape digging to the second rod. It's just my personal pet peeve.


The first pool I ever worked on was the first time I was the only one with a shovel on a job, I was 14 and hated every stinking minute of it. Had to be close to 100F as I trenched along while my cousin made up ground lugs.

So we see eye to eye on that pet peeve. :thumbsup:


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## drspec (Sep 29, 2012)

HackWork said:


> It's not even that. I will have a guy doing the panel change so I may do the ground rods myself while he's working on the panel or I may have him do them if I get lazy. But either way, I just hate having to spend the time and mess up the landscape digging to the second rod. It's just my personal pet peeve.


it doesnt take much effort to bury the ground wire

rake the mulch, straw, etc to the side, use the claw of your hammer to make a shallow ditch, push the dirt back over it with the head of the hammer and lightly tap the top of the dirt with a sledge hammer

takes less than 10 mins

Im lazy and even that doesnt bother me

now, actually driving the rods, that sucks


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## Bird dog (Oct 27, 2015)

*Ground Rod Rant*



HackWork said:


> It's not even that. I will have a guy doing the panel change so I may do the ground rods myself while he's working on the panel or I may have him do them if I get lazy. But either way, I just hate having to spend the time and mess up the landscape digging to the second rod. It's just my personal pet peeve.


Ok, so, this is really a rant about ground rods. We all hate doing them.


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## HackWork (Oct 2, 2009)

drspec said:


> it doesnt take much effort to bury the ground wire


 It's WAY more effort than it's worth.



> rake the mulch, straw, etc to the side, use the claw of your hammer to make a shallow ditch, push the dirt back over it with the head of the hammer and lightly tap the top of the dirt with a sledge hammer


 I have a very flat spade shovel that I can put into the dirt and then rock back and forth making a nice 4-6" deep crevice. Then I can put the GEC into it and stomp it closed. But it's still too much work since it's completely unnecessary. 



> Im lazy and even that doesnt bother me


 You're not a true lazy bastard.



> now, actually driving the rods, that sucks


 I don't mind that, Hilti takes care of it and it's even easier with 4' rods.


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## HackWork (Oct 2, 2009)

Bird dog said:


> Ok, so, this is really a rant about ground rods. We all hate doing them.


I don't mind driving a ground rod, I hate having to trench to the second ground rod that is completely unnecessary and the people who insist that it remains a code requirement can't even substantiate it's purpose.


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## splatz (May 23, 2015)

I can't dismiss that the ground resistance helps with lightning and surge protection, doesn't anyone else think that's of value? In my limited experience improving the grounding / bonding does seem to help with places that are prone to surge damage. 

I even see the 25Ω rule as a reasonable hedge - buy the tool or drive two rods - but I don't think it's realistic to incorporate a measurement into the electrical inspection process. 

It mostly pisses me off that the tool is too expensive.


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## HackWork (Oct 2, 2009)

splatz said:


> I can't dismiss that the ground resistance helps with lightning and surge protection, doesn't anyone else think that's of value? In my limited experience improving the grounding / bonding does seem to help with places that are prone to surge damage.
> 
> I even see the 25Ω rule as a reasonable hedge - buy the tool or drive two rods - but I don't think it's realistic to incorporate a measurement into the electrical inspection process.
> 
> It mostly pisses me off that the tool is too expensive.


What tool? In my research I haven't found anything that states what test or tool is required to be used.

As for the first part of your post, why is 25ohm a reasonable hedge? Why not 15ohm? Or 50ohm? Why is a second ground rod a smart idea? Why not a third, or fourth?

You can drive 15 ground rods into earth on one property that don't perform as well as 1 rod on another property. 

All of this is completely arbitrary and not substantiated in any valid way. We are literally just driving a second ground rod for "feel good" reasons.


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## drspec (Sep 29, 2012)

HackWork said:


> It's WAY more effort than it's worth.
> 
> I have a very flat spade shovel that I can put into the dirt and then rock back and forth making a nice 4-6" deep crevice. Then I can put the GEC into it and stomp it closed. But it's still too much work since it's completely unnecessary.
> 
> ...


I have a corded and cordless Milwaukee with the ground rod drive I use, but with the clay and rock here you still have to pound em em with a sledge hammer most of the time


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## splatz (May 23, 2015)

The tools - like these would satisfy the NEC requirement 

http://www.aemc.com/products/html/view.asp?id=501&dbname=products

They start around $1400. The testers for other standards that want a three point or four point test may be more or less $$ than that, but doing the test is much harder.


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## MechanicalDVR (Dec 29, 2007)

drspec said:


> I have a corded and cordless Milwaukee with the ground rod drive I use, but with the clay and rock here you still have to pound em em with a sledge hammer most of the time


You just need a heavier hammer drill to drive them.


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## drspec (Sep 29, 2012)

MechanicalDVR said:


> You just need a heavier hammer drill to drive them.


I guess the largest rotary demo hammer drill Milwaukee makes with 8.8 ft-lbs of blow energy and the Milwaukee cordless with 5.1 ft-lbs isnt enough?


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## splatz (May 23, 2015)

HackWork said:


> As for the first part of your post, why is 25ohm a reasonable hedge? Why not 15ohm? Or 50ohm? Why is a second ground rod a smart idea? Why not a third, or fourth?


Now that you mention it, why a first? Do you think grounding is necessary at all? I'll admit I don't really understand how it's supposed to work for electrical safety / NEC purposes. I am buying that it's useful for surge protection but is that in the scope of the NEC? 

If it was that important as a return path, wouldn't we just run a wire back to the utility transformer? 



> You can drive 15 ground rods into earth on one property that don't perform as well as 1 rod on another property.
> 
> All of this is completely arbitrary and not substantiated in any valid way. We are literally just driving a second ground rod for "feel good" reasons.


I am just saying that if you accept low ground resistance is deisrable but not critical and 25 ohms is sufficient, it's OK to let you off the hook with one rod instead of two if you can show that ground resistance. 

On the other hand since it isn't critical and depends on certain things (soil, moisture, drainage, etc.) that are impossible or impractical to control, you can drive two ground rods and call it good enough. 

(Would you agree that not everything in the code is really nailed down, there are things in load calcs, sizing breakers, etc. that are practical / good enough - hedges.)


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## MechanicalDVR (Dec 29, 2007)

drspec said:


> I guess the largest rotary demo hammer drill Milwaukee makes with 8.8 ft-lbs of blow energy and the Milwaukee cordless with 5.1 ft-lbs isnt enough?


Couldn't tell you what the blow energy is on my old Hilti but it drives a rod like a hot knife through butter without human hands. Just set it and forget it.


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## drewsserviceco (Aug 1, 2014)

MechanicalDVR said:


> Couldn't tell you what the blow energy is on my old Hilti but it drives a rod like a hot knife through butter without human hands. Just set it and forget it.



Blow energy sounds like something one should research before settling into a marriage. I would really hate to be misinformed on that statistic.


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## MechanicalDVR (Dec 29, 2007)

drewsserviceco said:


> Blow energy sounds like something one should research before settling into a marriage. I would really hate to be misinformed on that statistic.


Well as I have told many a girl over the years 'blow' is a misnomer on rating that job skill.:thumbsup:


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## Wiresmith (Feb 9, 2013)

how about 100'

you'll like this hackwork

excerpt from
https://www.engineereducators.com/docs/groundingandbonding2-2.pdf

There is a down side to driving longer, deeper rods in that the coupled rods can bend as they encounter denser soil. One project called for a contractor to couple and drive a 100’ ground rod in order to achieve 5 Ohm resistance in a stratified, sandy soil condition. As the contractor coupled and drove the fifth 10’section of rod, it was noticed that the “pointy end” of the ground rod was coming up under a car in the nearby parking lot.
[Deep Earth Grounding versus Shallow Earth Grounding, Computer Power Corporation by Martin D. Conroy and Paul G. Richard - http://www.cpccorp.com/deep.htm]


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## Big John (May 23, 2010)

splatz said:


> The tools - like these would satisfy the NEC requirement
> 
> http://www.aemc.com/products/html/view.asp?id=501&dbname=products


And ironically, much like the 25 ohm requirement itself, the numbers that thing gives you are often meaningless. But the plus side is they're usually wrong in your favor.

Most houses don't have SPDs, so ground rods aren't doing anything to help there. Even ones that do are dissipating very small amounts of energy: I have no proof, but I imagine you could have a very poor earth connection and still work fine. For example, static discharge systems only need resistances in the kilo-ohm range.

There's really not a hell of a lot that most electrodes do at a house. It's just a bunch of buried metal.


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## Wiresmith (Feb 9, 2013)

most people around here only drive one ground rod (i don't endorse the practice but inspectors around here indirectly do)


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## Jhellwig (Jun 18, 2014)

The power company here says drive two. 


And cutting an 8 footer in half doesn't count.


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## socket2ya (Oct 27, 2016)

Here's the closing paragraph from a good article on this subject from Electrical Construction and Maintenance. Full article here http://ecmweb.com/content/who-cares-about-25-ohms-or-less

"Impact of power quality. Believe it or not, nearly all electronic equipment will operate properly without the benefit of a low-resistance GES. Power quality site surveys have shown that in situations where the grounding electrode resistance is between 5 ohms and 105 ohms, it doesn't affect equipment. However, you can trace most problems to poor quality connections on the equipment-grounding system. Therefore, you should pay less attention to the GES measurement and more to the impedance of the equipment-grounding system and the verification of low-resistance bonding connections between grounding planes.

What's the lesson here? Spend less time on the testing and qualification of the GES resistance and more time checking the bonding between locations and the equipment-grounding conductor impedance.


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## socket2ya (Oct 27, 2016)

My only issue with cutting the ground rod in half is that cutting a ground is a decent amount of work in and of itself. I think I tried it once and it was pretty tough metal and took a while even with the sawzall. I guess it's still less work than pounding a ground rod. I've been using a cordless rotary hammer with driver which gets it down- but not not exactly like a hot knife through butter.


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## Big John (May 23, 2010)

socket2ya said:


> ...However, you can trace most problems to poor quality connections on the equipment-grounding system. Therefore, you should pay less attention to the GES measurement and more to the impedance of the equipment-grounding system and the verification of low-resistance bonding connections between grounding planes....


 On the one hand, I agree that bonding is far more critical than earthing, but this still reads like BS: 

"Trace most problems" to poor grounding? You only need good equipment grounds to try and mitigate the damage after a problem in the wiring has already happened. Otherwise equipment grounds are not part of any circuit and are serving no purpose.


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## socket2ya (Oct 27, 2016)

And one more question. Does anybody know if the copper rods are of better quality than the galvies, to the extent that only one copper rod needs to be driven to obtain the 25 ohms or less?


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## socket2ya (Oct 27, 2016)

Big John said:


> On the one hand, I agree that bonding is far more critical than earthing, but this still reads like BS:
> 
> "Trace most problems" to poor grounding? You only need good equipment grounds to try and mitigate the damage after a problem in the wiring has already happened. Otherwise equipment grounds are not part of any circuit and are serving no purpose.


Well that's true- you could have your perfectly good grounding system all dressed up with no where to go and it's pointless to have it


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## emtnut (Mar 1, 2015)

telsa said:


> A Ufer. :thumbsup:





HackWork said:


> So I should knock the house down and rebuild the foundation every time someone wants a service upgrade? Cause that would sure be easier than digging a trench to the second ground rod...


Of course not ....

But if you ask what is better than an 8' ground rod ..... :laughing:


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## emtnut (Mar 1, 2015)

Big John said:


> And ironically, much like the 25 ohm requirement itself, the numbers that thing gives you are often meaningless. But the plus side is they're usually wrong in your favor.
> 
> Most houses don't have SPDs, so ground rods aren't doing anything to help there. Even ones that do are dissipating very small amounts of energy: I have no proof, but I imagine you could have a very poor earth connection and still work fine. For example, static discharge systems only need resistances in the kilo-ohm range.
> 
> There's really not a hell of a lot that most electrodes do at a house. It's just a bunch of buried metal.


Lightning 'protection' .... nuthin else


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## Big John (May 23, 2010)

emtnut said:


> Lightning 'protection' .... nuthin else


I agree for large buildings with an engineered LPS good grounding becomes critical, but otherwise somebody would have to prove to me that a piddly code-minimum GES makes any difference at all for lightning strikes.


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## MechanicalDVR (Dec 29, 2007)

Jhellwig said:


> The power company here says drive two.
> 
> 
> And cutting an 8 footer in half doesn't count.


How would anyone but you know if you cut a rod in half?


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## telsa (May 22, 2015)

HackWork said:


> So I should knock the house down and rebuild the foundation every time someone wants a service upgrade? Cause that would sure be easier than digging a trench to the second ground rod...


Ufers don't require that you touch the old foundation.

You can ditch and puddle outside the existing foundation and get'er done. :notworthy:


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## splatz (May 23, 2015)

telsa said:


> Ufers don't require that you touch the old foundation.
> 
> You can ditch and puddle outside the existing foundation and get'er done. :notworthy:


I thought they had to be attached to the foundation or footer and located near the bottom?


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## telsa (May 22, 2015)

splatz said:


> I thought they had to be attached to the foundation or footer and located near the bottom?


I've done just as I've described -- and it passed with flying colors. 

It's standard fare around here.


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## telsa (May 22, 2015)

The posts, here, indicate total corn fusion WRT grounding.

It DEFLECTS lightning strikes by pulling the building's field wiring -- the green and neutral -- down towards LOCAL ground potential.

This means that the field wiring -- electrically -- blends into the local back ground.

So lightning NEVER strikes in the first place. Instead, it erupts out of some tree, down the road.

If lightning does strike, the GEC system is absolutely no protection whatsoever. 

Great damage will be done. #6, #4, #2 not one of them can handle the amps involved.

The GEC also protects the equipment within a building -- especially junk like wall warts and the rest. It bleeds off transient spikes that are generated every time anyone throws a switch.

These transients are so trivial ( energy wise ) that they are never discussed. If they can bleed into the GEC, then they won't harm any insulation. 

If they have no-where to go, they can reach astounding levels.

The collapsing field of a transformer will generate astounding voltages. 

The old fashioned automotive coil -- used to fire spark plugs two-generations ago -- generated 25,000 VDC (pulse, only) out of 6-14 VDC.

Yup. Without it, the motors would never run. Think about it.

That's the kind of voltage multiplication possible with a collapsing DC field.

The GEC causes all such events to bleed straight into the earth.

THAT'S why you MUST ground and bond residential systems.

Ungrounded systems have all kinds of goofy side problems that we don't encounter, 'cause the NEC won't let us encounter them.


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## HackWork (Oct 2, 2009)

socket2ya said:


> My only issue with cutting the ground rod in half is that cutting a ground is a decent amount of work in and of itself. I think I tried it once and it was pretty tough metal and took a while even with the sawzall. I guess it's still less work than pounding a ground rod. I've been using a cordless rotary hammer with driver which gets it down- but not not exactly like a hot knife through butter.


The M12 bandsaw cuts thru it like butter. A sawzall will cut it, but it's more work.


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## HackWork (Oct 2, 2009)

telsa said:


> Ufers don't require that you touch the old foundation.
> 
> You can ditch and puddle outside the existing foundation and get'er done. :notworthy:


I don't believe that would be a compliant Ufer.

But even if it would be, it would have to be 20' long and poured in concrete, which is a hell of a lot harder than pushing a 6' piece of #6 into the dirt.


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## telsa (May 22, 2015)

HackWork said:


> I don't believe that would be a compliant Ufer.
> 
> But even if it would be, it would have to be 20' long and poured in concrete, which is a hell of a lot harder than pushing a 6' piece of #6 into the dirt.


Back in the Real World, I could get away with a coil of #4 stuffed round and round into a squat pocket.

If this sounds like a ground plate... I'd say it's pretty close.

You must understand our local 'soil'... as driving a ground rod is virtually impossible.

So it's Ufers every time.


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## MechanicalDVR (Dec 29, 2007)

telsa said:


> Back in the Real World, I could get away with a coil of #4 stuffed round and round into a squat pocket.
> 
> If this sounds like a ground plate... I'd say it's pretty close.
> 
> ...


If it's so hard to just drive a rod how is it easier to dig up a hole for a Ufer?


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## telsa (May 22, 2015)

MechanicalDVR said:


> If it's so hard to just drive a rod how is it easier to dig up a hole for a Ufer?


Mr. Backhoe.

Yup.

BTW, Ufers permit you to get'er done without going so _deep_.

In most locations, going down 8 feet is impossible without high power back hoes...

Or nitro.


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## MechanicalDVR (Dec 29, 2007)

telsa said:


> Mr. Backhoe.
> 
> Yup.
> 
> ...


I was under the impression they had to be footing depth.


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## telsa (May 22, 2015)

MechanicalDVR said:


> I was under the impression they had to be footing depth.


They have to be deep enough to satisfy the AHJ... and SAFE from future excavation, disturbance... think in terms of 24" of cover.

So, there's the need to co-ordinate with the AHJ.


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## macmikeman (Jan 23, 2007)

You guys don't ever read the Code 250 much huh?


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## splatz (May 23, 2015)

HackWork said:


> I don't believe that would be a compliant Ufer.
> 
> But even if it would be, it would have to be 20' long and poured in concrete, which is a hell of a lot harder than pushing a 6' piece of #6 into the dirt.


You have to use 20' of metal but it doesn't have to be one straight piece. You could take 20' of #4, bend it in a corkscrew, and encase that in concrete. 

The idea with the ufer is that the same electrode works better in concrete than if you just buried the same electrode in the soil. I am not sure why it would have to be tied to the building's foundation, or why it would have to be buried at the bottom. If you look at it like a plate electrode that doesn't make much sense.


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## MechanicalDVR (Dec 29, 2007)

macmikeman said:


> You guys don't ever read the Code 250 much huh?


Thanks for the reference number.


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## MechanicalDVR (Dec 29, 2007)

Section 250.52(A)(3) clearly specifies what constitutes a concrete-encased electrode. The concrete-encased electrode can be bare, zinc-galvanized, or other steel reinforcing bars or rods of not less than ½ inch in diameter coated in electrically conductive material. It can be installed in one continuous 20-foot length, or, if in multiple pieces, it can be connected by the usual steel tie wires, exothermic welding, welding or other effective means to create a 20-foot or greater length. A concrete-encased electrode can also be constructed using 20 feet or more of bare copper conductor not smaller than 4 AWG. Note that the 20 feet of conductive rods or bare wire used in creating a concrete-encased electrode only establishes the connection to the concrete. The combination of the concrete and the conductive component serve as the grounding electrode as clarified in the definition of the term. 

Mandatory grounding electrode system 

Section 250.50 mandates the use of all grounding electrodes to form the grounding electrode system. This includes all concrete-encased electrodes present at the building or structure. An exception to Section 250.50 relaxes this mandatory requirement for existing buildings and structures in which connecting the concrete-encased electrode could damage the structural integrity of the building or otherwise disturb the existing construction. (Because the installation of the footings and foundation is one of the first elements of a construction project and, in most cases, has been completed by the time the electric service is installed, this rule necessitates an awareness and coordinated effort from designers and the construction trades to ensure the concrete-encased electrode is incorporated into the grounding electrode system during the placement of rebar and concrete footings.) If a concrete-encased electrode is not present at the building or structure, it is not required that a 4 AWG copper wire be used to form one, but it is an option. 

Electrode performance 

The concrete-encased electrode has proven that it offers optimal performance and longevity. The footing or foundation of any building will typically be there as long as the building is. Because all of the rebar in the bottom perimeter of the building footing is usually tied together with tie wires, the electrode acts similar to a ground ring, only it has much more surface area in the concrete connection to the earth. The footing is present around the bottom of the building perimeter, which means there is significant ground (earth) contact from concrete-encased electrodes. Concrete retains moisture and is continuously absorbing moisture through the bottom of the footing. This ensures an effective connection between the footing and the earth. The footing of a building is also typically the largest grounding electrode in each structure.


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## wendon (Sep 27, 2010)

HackWork said:


> So I should knock the house down and rebuild the foundation every time someone wants a service upgrade? Cause that would sure be easier than digging a trench to the second ground rod...


What's so hard about digging a trench? Is there even a minimum depth if you use a #4 like you should be? Quit whining and dig the trench.

Sent from my SAMSUNG-SM-G870A using Tapatalk


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## HackWork (Oct 2, 2009)

wendon said:


> What's so hard about digging a trench? Is there even a minimum depth if you use a #4 like you should be? Quit whining and dig the trench.
> 
> Sent from my SAMSUNG-SM-G870A using Tapatalk


What kind of idiot would use #4 for ground rods?


----------



## drewsserviceco (Aug 1, 2014)

I just go back to the house with the ground wire, run along the house with straps and than back out to second rod. No trenching necessary.


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## wendon (Sep 27, 2010)

HackWork said:


> I don't believe that would be a compliant Ufer.
> 
> But even if it would be, it would have to be 20' long and poured in concrete, which is a hell of a lot harder than pushing a 6' piece of #6 into the dirt.


Are you sure? From your previous posts, it sounded like a daunting task![emoji1] 

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## wendon (Sep 27, 2010)

HackWork said:


> What kind of idiot would use #4 for ground rods?


A smart one. You don't have to worry about physical protection.

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## HackWork (Oct 2, 2009)

drewsserviceco said:


> I just go back to the house with the ground wire, run along the house with straps and than back out to second rod. No trenching necessary.


Yeah, we could do that here too. We are not in one of those areas that require the GEC to be in pipe and protected.

My main gripe here is that the second ground rod is often a problem. Some houses don't have a front yard, it's all cement. SO I could get 1 ground rods in somewhere, but the second one 6' a way becomes a problem.

The other day I had to run about 75' of #6 thru a finished basement to get to the back of the house because that was the only place that would accommodate 2 ground rods 6' away. 

I've had many situations in which I could drive the first ground rod easily, but the second was a pain. And since its a completely arbitrary thing, it should be banished!


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## HackWork (Oct 2, 2009)

wendon said:


> A smart one. You don't have to worry about physical protection.
> 
> Sent from my SAMSUNG-SM-G870A using Tapatalk


That's not true. Don't put your stupid local requirements on all of us. We go by the NEC.

"A 4 AWG or larger copper or aluminum grounding electrode conductor shall be protected if exposed to physical damage."


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## wendon (Sep 27, 2010)

HackWork said:


> That's not true. Don't put your stupid local requirements on all of us. We go by the NEC.
> 
> "A 4 AWG or larger copper or aluminum grounding electrode conductor shall be protected if exposed to physical damage."


Right, but your #6 has to be either fastened to the structure, or protected by pipe. 250.64 (B) 

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## HackWork (Oct 2, 2009)

wendon said:


> Right, but your #6 has to be either fastened to the structure, or protected by pipe. 250.64 (B)
> 
> Sent from my SAMSUNG-SM-G870A using Tapatalk


Yup, we strap it to the foundation until it goes into the dirt. A couple little 1-hole straps and tapcons. Still no reason to use #4.


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## Barjack (Mar 28, 2010)

I've always had trouble with this article:



> *250.64*
> *(B) Securing and Protection Against Physical Damage.*
> Where exposed, a grounding electrode conductor or its enclosure
> shall be securely fastened to the surface on which it
> ...


To me, it looks like it says the same thing for both #4 and #6.


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## wendon (Sep 27, 2010)

HackWork said:


> Yup, we strap it to the foundation until it goes into the dirt. A couple little 1-hole straps and tapcons. Still no reason to use #4.


Strap away. We've always been advised to use #4 to avoid any conflicts. Better yet, I'll let you use my AEMC, you can wait for the POCO to show up, and then you can prove to them that you've achieved 25 ohms with one G-rod.[emoji106] 

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## HackWork (Oct 2, 2009)

Barjack said:


> I've always had trouble with this article:
> 
> 
> 
> To me, it looks like it says the same thing for both #4 and #6.


Agreed. It does.


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## HackWork (Oct 2, 2009)

wendon said:


> Strap away. We've always been advised to use #4 to avoid any conflicts. Better yet, I'll let you use my AEMC, you can wait for the POCO to show up, and then you can prove to them that you've achieved 25 ohms with one G-rod.
> 
> Sent from my SAMSUNG-SM-G870A using Tapatalk


The power company here doesn't care about any of it. I checked the book just to be sure and it says to install ground rod to code or something similar. It's the NEC and town inspectors that this thread is about.


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## wendon (Sep 27, 2010)

HackWork said:


> Agreed. It does.


I disagree. There are different requirements for the two. How the inspector interprets them might be interesting......

A 4 AWG shall be protected if exposed to physical damage.

A 6 AWG w/o exposure to physical damage, shall be permitted to be run along the surface of the building construction without metal covering or protection if it is securely fastened to the constuction; otherwise it shall be protected in RMC, etc.


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## drewsserviceco (Aug 1, 2014)

Thoughts on driving a rod through the basement floor or wall?? And before the naysayers say you can't fit an 8' rod and hammer drill upright in the basement, the code allows as much as a 45* angle. 

I have my opinion, wandering what you guys think.


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## MechanicalDVR (Dec 29, 2007)

HackWork said:


> What kind of idiot would use #4 for ground rods?


#4 is sure a lot easier to bend in a cork screw pattern than rebar!


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## HackWork (Oct 2, 2009)

drewsserviceco said:


> Thoughts on driving a rod through the basement floor or wall?? And before the naysayers say you can't fit an 8' rod and hammer drill upright in the basement, the code allows as much as a 45* angle.
> 
> I have my opinion, wandering what you guys think.


I have had to do this in some places that had no outside area without cement.

I don't like doing it because I don't want to be responsible for water leaks.


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## wendon (Sep 27, 2010)

Barjack said:


> I've always had trouble with this article:
> 
> 
> 
> To me, it looks like it says the same thing for both #4 and #6.


I agree. We usually strap ours to the riser etc. A state inspector tried explaining this but the conclusion was just to use #4 to avoid any issues.

The beginning of the article states that the conductor shall be securely fastened to the surface on which it is carried.

The second part appears to create different requirements for the two conductors.

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## HackWork (Oct 2, 2009)

wendon said:


> I disagree. There are different requirements for the two. How the inspector interprets them might be interesting......
> 
> A 4 AWG shall be protected if exposed to physical damage.
> 
> ...


Neither can be exposed to physical damage, would you agree with that?


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## Bird dog (Oct 27, 2015)

MechanicalDVR said:


> Electrode performance
> 
> The concrete-encased electrode has proven that it offers optimal performance and longevity. The footing or foundation of any building will typically be there as long as the building is. Because all of the rebar in the bottom perimeter of the building footing is usually tied together with tie wires, the electrode acts similar to a ground ring, only it has much more surface area in the concrete connection to the earth. The footing is present around the bottom of the building perimeter, which means there is significant ground (earth) contact from concrete-encased electrodes. Concrete retains moisture and is continuously absorbing moisture through the bottom of the footing. This ensures an effective connection between the footing and the earth. The footing of a building is also typically the largest grounding electrode in each structure.


Just as long as they didn't put down a moisture barrier.


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## wendon (Sep 27, 2010)

I always hated driving ground rods until I purchased a Bosch demolition hammer.......

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## wendon (Sep 27, 2010)

HackWork said:


> Neither can be exposed to physical damage, would you agree with that?


Agreed. What is "exposed to physical damage" ? Any green inspector, void of any common sense, can put his own spin on this one. Does your inspector require you to leave the ground rods exposed until after the inspection?

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## HackWork (Oct 2, 2009)

wendon said:


> Agreed. What is "exposed to physical damage" ? Any green inspector, void of any common sense, can put his own spin on this one. Does your inspector require you to leave the ground rods exposed until after the inspection?
> 
> Sent from my SAMSUNG-SM-G870A using Tapatalk


I work in so many different towns that it's hard to know what each inspector wants. So I usually drive the ground rod about 1" below grade and then leave the top exposed so they can see the acorn. I will leave a small pile of dirt next to it and tell the customer to kick the dirt into the hole to cover the ground rod after the inspection.


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## wendon (Sep 27, 2010)

HackWork said:


> I work in so many different towns that it's hard to know what each inspector wants. So I usually drive the ground rod about 1" below grade and then leave the top exposed so they can see the acorn. I will leave a small pile of dirt next to it and tell the customer to kick the dirt into the hole to cover the ground rod after the inspection.


And when the town drunk trips over them in the dark whilst out window peeping, he sues the electrician.......

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## HackWork (Oct 2, 2009)

wendon said:


> And when the town drunk trips over them in the dark whilst out window peeping, he sues the electrician.......
> 
> Sent from my SAMSUNG-SM-G870A using Tapatalk


LOL, ok.


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## Bird dog (Oct 27, 2015)

telsa said:


> The posts, here, indicate total corn fusion WRT grounding.
> 
> It DEFLECTS lightning strikes by pulling the building's field wiring -- the green and neutral -- down towards LOCAL ground potential.
> 
> ...


It seems customers at the end of a utility line have these problems. I guess all you can do is insure proper grounding/bonding & really good surge protection, then, hope for the best. The real fix is for the utility to extend their line I guess.


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## wendon (Sep 27, 2010)

Bird dog said:


> It seems customers at the end of a utility line have these problems. I guess all you can do is insure proper grounding/bonding & really good surge protection, then, hope for the best. The real fix is for the utility to extend their line I guess.


Considering that about 40% of the POCO's return neutral current travels through the earth, I would suppose they appreciate any help they can get.....
If it was up to me, I'd ask them to add another conductor and get rid of the primary neutral.
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## Big John (May 23, 2010)

Bird dog said:


> It seems customers at the end of a utility line have these problems....


 In my experience customers at the end of spurs have more problems because of voltage drop, poor regulation, and poorer surge protection.

Doesn't have much to do with connections to earth.


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## RePhase277 (Feb 5, 2008)

telsa said:


> The posts, here, indicate total corn fusion WRT grounding.
> 
> It DEFLECTS lightning strikes by pulling the building's field wiring -- the green and neutral -- down towards LOCAL ground potential.
> 
> ...


I'll give you the part about the grounding electrode being meant to avoid a strike, not absorb one. That's true and is the same theory for air terminals (aka "lightning rods"): bleed off the charge before it builds up to the point of arcing over into a full-blown bolt.

But the part about bleeding off the energy of collapsing fields, I'm not so sure about. The energy in the field tries to continue along the same circuit that generated it, which doesn't involve the earth to begin with. So how does having the grounding electrode help with that? Seems to me that problem is solved by reverse-biased diodes that short the current when it happens.


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## Big John (May 23, 2010)

Yeah, inductive kicks aren't going to ground. If they were, every wall-wart and kitchen blender would need MOVs and a three-prong plug.

I don't even think most appliances try to address that: It's not that big a deal with relatively slow-moving air switches and small AC coils.


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## telsa (May 22, 2015)

RePhase277 said:


> I'll give you the part about the grounding electrode being meant to avoid a strike, not absorb one. That's true and is the same theory for air terminals (aka "lightning rods"): bleed off the charge before it builds up to the point of arcing over into a full-blown bolt.
> 
> But the part about bleeding off the energy of collapsing fields, I'm not so sure about. The energy in the field tries to continue along the same circuit that generated it, which doesn't involve the earth to begin with. So how does having the grounding electrode help with that? Seems to me that problem is solved by reverse-biased diodes that short the current when it happens.


These are L-N loads.

The power may have come in by way of the hot... but the collapsing field energy can always exit by way of the grounded neutral.

If the primary coil is L-N, then the secondary winding never gets 'crazy' either.


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## telsa (May 22, 2015)

Solid state switching transients have proved to be such a problem that we've..

1) up-sized neutrals

2) up-graded insulation

3) even added reactors ( typ industrial control circuits) to dump energy

It's notable that we've had to address both the hots and the returns. 

Since solid state switching circuits are loaded with capacitors, one can think of them as the mirror image of wall warts. 

Both store energy that can prove destructive if not 'vented' away. 

Again, these are secondary, even tertiary effects, not the stuff of apprenticeship lectures.*

They have been shown to damage conductor insulation... especially with time in service. 

* They have left many an EE with egg on his face, too.

Thirty-years ago, EEs were going nuts trying to get PCs up past 200 mHz. 

It was these switching transients that blocked the way. 

( I had a pal who almost went insane chasing them down. Correct that, he did go insane. )

The matter was resolved by simply adding additional grounding conductors so that each switching hot ( +VDC ) had its own exclusive return to dump energy. Any other approach left the electrons in a 'voltage stacking' 'traffic jam.'

The digital logic is based upon voltage differences and micro-capacitors. If the dump line is clogged with electrons, then the voltage difference collapses -- and the logical stage is promptly scrambled. It loses its mind// machine state.

We now have solid state switching devices all over North America. (eg your TV ) Every last one of them wants a clean path to local ground potential.

You'd better provide it, or strange things will happen.

As for dirt work, generally, it's the kind of work that makes customers dial out. They are even less happy to ditch than we are. 

And apprentices have to start somewhere. So give the young troops a break.

[ I swear by my Hilti 76-P. ]


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## Jhellwig (Jun 18, 2014)

]


HackWork said:


> What kind of idiot would use #4 for ground rods?


If you have more than one grounding electrode and have more than a 100 amp service you can't use 6.


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## RePhase277 (Feb 5, 2008)

Jhellwig said:


> ]
> 
> If you have more than one grounding electrode and have more than a 100 amp service you can't use 6.


Que?


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## HackWork (Oct 2, 2009)

Jhellwig said:


> ]
> 
> If you have more than one grounding electrode and have more than a 100 amp service you can't use 6.


Nope. Ground rods only require a #6.


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## Jhellwig (Jun 18, 2014)

RePhase277 said:


> Que?


Maybe I was thinking grounding electrode conductor. If you have a sole grounding electrode conductor you don't have to use anything larger than 6 even if it is a 2000 amp service. Anything else you have to use the chart.


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## Jhellwig (Jun 18, 2014)

HackWork said:


> Nope. Ground rods only require a #6.



No. I don't have a code book near me but I am fairly sure you are wrong.


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## RePhase277 (Feb 5, 2008)

Jhellwig said:


> No. I don't have a code book near me but I am fairly sure you are wrong.


Better grab that code book. A ground rod connection is only required to be #6 at the most. By the NEC anyway, POCOs can and often do spec larger.

A Ufer is only required to be #4 at most. Other types of electrodes are sized by the size of the ungrounded conductors.


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## HackWork (Oct 2, 2009)

Jhellwig said:


> No. I don't have a code book near me but I am fairly sure you are wrong.


That's too bad. I thought you and I had something.


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## HackWork (Oct 2, 2009)

250.66(A) Connections to Rod, Pipe, or Plate Electrodes. Where the grounding electrode conductor is connected to rod, pipe, or plate electrodes as permitted in 250.52(A)(5) or 250.52(A)(6), that portion of the conductor that is the sole connection to the grounding electrode shall not be required to be larger than 6 AWG copper wire or 4 AWG aluminum wire.


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## RePhase277 (Feb 5, 2008)

HackWork said:


> That's too bad. I thought you and I had something.


You have got to be f'king kidding me... if this guy moves in with you and Borgi, I'm going to be so pissed


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## LARMGUY (Aug 22, 2010)

HackWork said:


> Yes, but gold is better for connections because it doesn't tarnish like silver.


Silver does not tarnish in the ground only in air. Just ask any detectorist.


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## LARMGUY (Aug 22, 2010)

Suncoast Power said:


> I think it would disappear before the first strike.


Like a copper rod and some gold spraypaint?


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## telsa (May 22, 2015)

LARMGUY said:


> Silver does not tarnish in the ground only in air. Just ask any detectorist.


That's not absolutely true.

Silver is attacked something crazy by nitrates... so common in fertilizers.


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## MechanicalDVR (Dec 29, 2007)

telsa said:


> That's not absolutely true.
> 
> *Silver is attacked something crazy by nitrates*... so common in fertilizers.


Absolutely correct!


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## LARMGUY (Aug 22, 2010)

So is copper and nickel.


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## TGGT (Oct 28, 2012)

drsparky said:


> A gold plated 8' ground rod would probably test good, solid gold would be even better. Hard part is up selling the idea to the customer. :brows:


I believe copper is only second to silver in conductivity.

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## Jhellwig (Jun 18, 2014)

RePhase277 said:


> Better grab that code book. A ground rod connection is only required to be #6 at the most. By the NEC anyway, POCOs can and often do spec larger.
> 
> A Ufer is only required to be #4 at most. Other types of electrodes are sized by the size of the ungrounded conductors.


Hrmmm.... I know I was rusty but didn't think I was that rusty.



HackWork said:


> That's too bad. I thought you and I had something.


You will always have a special place in my heart.


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## sbrn33 (Mar 15, 2007)

RePhase277 said:


> I make that gamble based on the POCO spec. Chances are, if the POCO spec sheet only shows one rod, the inspector is only looking for one as well. Sometimes.
> 
> The code doesn't specify how the 25 ohms is to be verified. Stick a hot wire to the rod and use Ohm's Law to calculate the resistance. It's as valid as any other means.


The POCO spec and the nec have nothing to do with each other.


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## RePhase277 (Feb 5, 2008)

sbrn33 said:


> The POCO spec and the nec have nothing to do with each other.


Right. That's why it's a gamble. In many places I work, the POCO is part of the city government, so they are somewhat coordinated with the AHJ. In those jurisdictions, there's a good chance that if the spec sheet says one rod, the inspector isn't looking for much either.


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## sparkiez (Aug 1, 2015)

You can always drive your ground rod and then ohm between your unlanded neutral and the ground, which is usually what we do. We were just informed our services require two ground rods even though with the soil around here we easily get under 25 ohms with a single 8 ft ground rod.


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## Big John (May 23, 2010)

sparkiez said:


> You can always drive your ground rod and then ohm between your unlanded neutral and the ground, which is usually what we do. We were just informed our services require two ground rods even though with the soil around here we easily get under 25 ohms with a single 8 ft ground rod.


 I think that's a great loophole, so if your inspector buys that, go for it.

That said, the reason that's not a valid test is the reason the clamp-on ammeters are also not valid:

I bet a box of donuts there is usually something conductive bridging most of the gap between the house and the utility neutral ground: A metal fence, metal water pipe, metal gas line, phone conductor messenger, CATV shield, something.

You're just reading the little bit of resistance it takes for the ground electrode to get onto that easy parallel path: It's not an accurate measurement of how well the electrode actually connects to the earth overall.


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## RePhase277 (Feb 5, 2008)

Big John said:


> I think that's a great loophole, so if your inspector buys that, go for it.
> 
> That said, the reason that's not a valid test is the reason the clamp-on ammeters are also not valid:
> 
> ...


I don't believe an ohm meter is valid because it isn't driving any real current to see a voltage drop across the electrode-earth interface. But a clamp on ammeter measuring a current flowing into the earth from a hot wire connected to the rod is valid because even with other metal pathways helping out, the resistance of the electrode-earth connection will still have to be at least as low as the value that would allow the measured current to flow.


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## Big John (May 23, 2010)

I think the point is if electrode resistance is actually important, like for fault clearing on overhead lines or a lightening protection system, then you can't rely on the unintentional parallel paths:

I could string a piece of #22 phone wire between my electrode and the utility neutal and it would read a fantastic "low impedance" but were it ever actually needed to dissipate a lightening strike obvious it'd fail mightily.

That said, it doesn't matter with a house or even most commercial buildings, so I honestly don't care if he's "fudging" the numbers a bit.


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## PokeySmokey (Nov 14, 2017)

*Better than 1 8 foot ground rod*



HackWork said:


> Two 4 footers of course. But that still requires me to dig a trench to the second rod, which sucks.
> 
> Has anyone ever just driven 1 ground rod and then made the gamble on whether the inspector would be willing to wait around to test it? I'm thinking about trying that... 25 ohms bitches!


2 10 foot Ground Rods and a good Rod Driver.

Driven in hundreds this way in all types of soil.

If the soil is shallow with bedrock below drive them in on an angle preferable parallel to a septic tile bed.


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## flyboy (Jun 13, 2011)

socket2ya said:


> If you were to use a sledge to pound a gold ground rod, I envision there being quite a mushroom effect on the top of the rod. No sliding the acorn over that


You put the solid gold acorn connector on _before_ you start pounding on it. :thumbsup:


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## flyboy (Jun 13, 2011)

Ever notice when you use the bottom half of the rod it goes in with 2 or 3 wacks and never mushrooms over to hide the cut? 

I would never do that, I was just wondering if that ever happens. :no:


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## MechanicalDVR (Dec 29, 2007)

PokeySmokey said:


> 2 10 foot Ground Rods and a good Rod Driver.
> 
> Driven in hundreds this way in all types of soil.
> 
> If the soil is shallow with bedrock below drive them in on an angle preferable parallel to a septic tile bed.


Welcome aboard!

You should introduce yourself, just saw you were new here.


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## jiffy117 (May 11, 2017)

Had inspector get pissed because I put 2 8' ground rods in. Says 1 rod and water/gas lines would be enough. I almost offered to cut out wire going to second ground rod... would have cost me more to come back and put a 2nd rod, so wasn't worth it to chance doing 1. Can't win.


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## RePhase277 (Feb 5, 2008)

jiffy117 said:


> Had inspector get pissed because I put 2 8' ground rods in. Says 1 rod and water/gas lines would be enough. I almost offered to cut out wire going to second ground rod... would have cost me more to come back and put a 2nd rod, so wasn't worth it to chance doing 1. Can't win.


That's perfectly within code. Tell him to cite you a specific code article.


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## MCasey (Dec 7, 2016)

Three eight foot grund rods is better than one


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## 3DDesign (Oct 25, 2014)

MCasey said:


> Three eight foot grund rods is better than one


Three eight foot rods, more than 8 ft apart, in a triangle and connected back to the first rod, in other words, complete the triangle. 
The is good method for lightning and surge protection.


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## lighterup (Jun 14, 2013)

RePhase277 said:


> That's perfectly within code. Tell him to cite you a specific code article.


Okay... Is everyone ready for the newest code interpretation
from your truly?

MY CODE INSTRUCTOR just taught that 250.53 (A) _specifically_ 
(2) states that the additional electrode that jiffy117
installed is required ...was his inspector wrong for 
telling him otherwise? (2014 code ref)


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## HackWork (Oct 2, 2009)

lighterup said:


> Okay... Is everyone ready for the newest code interpretation
> from your truly?
> 
> MY CODE INSTRUCTOR just taught that 250.53 (A) _specifically_
> ...


jiffy's inspector was wrong because you can put in as many ground rods as you want to. 

As for what you instructor said, here is the code:



> (2) Supplemental Electrode Required. A single rod, pipe,
> or plate electrode shall be supplemented by an additional
> electrode of a type specified in 250.52(A)(2) through
> (A)(8). The supplemental electrode shall be permitted to be
> ...


Notice the exception that I bolded.

So you either need a second ground rod or you need to prove 25 ohms or less resistance.

We all install the second ground rod so that we don't have to go to the trouble of proving the resistance of the single rod.


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## lighterup (Jun 14, 2013)

HackWork said:


> jiffy's inspector was wrong because you can put in as many ground rods as you want to.
> 
> As for what you instructor said, here is the code:
> 
> ...


Yep , I saw that , but this guy claims it's damn near impossible
to meet the 25 ohms criteria so he stated he would red tag the
job without the supplemental rod.

I agree with you . I install (2) 8' ground rods.

As a matter of fact ., I recently purchased a12 amp Bosch SDL MAX
hammer drill (my old SDL is burning up- had it 17 years)...also
bought the hammer drill ground rod driver attachment.

Drives them down very nicely.


----------



## HackWork (Oct 2, 2009)

lighterup said:


> Yep , I saw that , but this guy claims it's damn near impossible
> to meet the 25 ohms criteria so he stated he would red tag the
> job without the supplemental rod.
> 
> ...


The driving them in part is easy with a big rotary hammer like you said. The part I don't like it digging the ditch to run the GEC to the second rod.


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## telsa (May 22, 2015)

HackWork said:


> I don't believe that would be a compliant Ufer.
> 
> But even if it would be, it would have to be 20' long and poured in concrete, which is a hell of a lot harder than pushing a 6' piece of #6 into the dirt.


The mental image that a Ufer HAS TO BE a linear run is clouding your mind.

I've plopped Ufers into 30" square holes -- right where it suited me.

REMEMBER, many locations have non-soils -- stuff like ledge -- and worse.

A Ufer that can be set a mere 24" down in a hole -- is MUCH faster in such cases.

The copper is largely COILED in such schemes.

Such a Ufer is not only much faster, but has a drastically better connection to the earth.

You're in Jersey... ground rods sound like easy driving out your way... garden state and all.

&&&

BTW, it's a BLESSING that driving ground rods// setting Ufers is beyond the ken of the trunk slammer// DIY crowd.

Easy money, then, when you come equiped -- with tools that no trunk slammer can ever afford.


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## telsa (May 22, 2015)

jiffy117 said:


> Had inspector get pissed because I put 2 8' ground rods in. Says 1 rod and water/gas lines would be enough. I almost offered to cut out wire going to second ground rod... would have cost me more to come back and put a 2nd rod, so wasn't worth it to chance doing 1. Can't win.


The inspector was WRONG.

Bonding to water is only suitable as an auxiliary element of the GEC System.

It can no longer _substitute_ for the essentials.

Why ?

Plastic plumbing connections.

What used to be is no longer operative.


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## telsa (May 22, 2015)

flyboy said:


> You put the *solid gold acorn connector* on _before_ you start pounding on it. :thumbsup:


I would think that they are too soft for this application. 

They would be corrosion proof, I'll give you that. :laughing:


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## Wiresmith (Feb 9, 2013)

> A static charge, on metallic objects, produced by a common high voltage surge,
> Will reach equilibrium with the earth within 10 seconds when connected by not more than 25 Ohms resistance in the path to the earth.
> 
> The initial surge will have a time domain of 2 to 10 ms. The resultant electrostatic charge will not equalize in a short time, if there is a high resistance path between the negative and positive charges.


Charles Coulomb and Johann Gauss, 
through unreliable source, don't take it for gospel


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## Going_Commando (Oct 1, 2011)

telsa said:


> jiffy117 said:
> 
> 
> > Had inspector get pissed because I put 2 8' ground rods in. Says 1 rod and water/gas lines would be enough. I almost offered to cut out wire going to second ground rod... would have cost me more to come back and put a 2nd rod, so wasn't worth it to chance doing 1. Can't win.
> ...


I would agree the inspector was probably wrong, depending on soil conditions, but bonding metal water piping is far more than "auxiliary". 

I cant barely get under 25 ohms to ground here with a 250' long ground grid with my ground resistance tester, so 2 ground rods is a given, even if they are pointless. Last ufer i did was in a sawcut trench in a concrete floor where i tied a couple 10' pieces of rebar onto vertical rebar to hold them in the crete. Easy peasy, and cheap. Plus im not unfamiliar with tying rebar due to the summer job for 6 years when i was in school.


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## Bird dog (Oct 27, 2015)

telsa said:


> The mental image that a Ufer HAS TO BE a linear run is clouding your mind.
> 
> I've plopped Ufers into 30" square holes -- right where it suited me.
> 
> ...


Also, the #6 on utility poles are coiled up & thrown in the hole then the power pole is set on top of it.


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## MTW (Aug 28, 2013)

This is a pro forum, how dare you suggest such a thing.


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