# When did code require 2 ground rods on 200a service



## LibertyRising (Jan 2, 2018)

I was under the impression that 2 ground rods have been required for 200a services for a long time, and we have a house that was built in the 90s, 1 ground rod 200a.

We are adding a second but just wondering when it came to be that 2 were required? More of a general knowledge question


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## Bird dog (Oct 27, 2015)

It's easier to drop two ground rods rather than meet the 25ohm rule.


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## LibertyRising (Jan 2, 2018)

Was it always 25ohms? I understand you can do either or, but was there a point in time where 200a services were sufficient with only 1 ground rod? When did the 2 ground rods (or 25 ohms) rule apply?


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## LibertyRising (Jan 2, 2018)

It’s a little disagreement I was having with the homeowner- he said the inspector told him that the house wasn’t required to have 2 ground rods in the 90s, so I am trying to figure out where the truth is- because as mentioned it could still only be 1 ground rod provided we can prove 25ohms. We didn’t replace the grounding system when we did swapped a panel out inside the home under the assumption that the ground was still ok. Verified it was there but couldn’t locate the 2nd one, let it go, and the inspections dinged it. 

I just wonder if there was a time that on a 200a service only required 1 ground with no strings attached


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## 360max (Jun 10, 2011)

1978 nec


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## LibertyRising (Jan 2, 2018)

Thank you!!


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## flyboy (Jun 13, 2011)

I don't think the code does require 2 grounds. It requires 25 ohms to ground

Some utilities require 2 ground rods in their specs.


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## Helmut (May 7, 2014)

flyboy said:


> I don't think the code does require 2 grounds.


The term grounding electrode is what you might be after.


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## flyboy (Jun 13, 2011)

Helmut said:


> The term grounding electrode is what you might be after.


Yeah I'm with you on the term grounding electrode. He's the one who is referencing two "ground rods".


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## LibertyRising (Jan 2, 2018)

I should be more technically correct when I’m talking about stuff I’m building my career around, but I’m not always.


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## Bird dog (Oct 27, 2015)

LibertyRising said:


> I should be more technically correct when I’m talking about stuff I’m building my career around, but I’m not always.


Sounds more like you need to take some continuing education. :wink:


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## HackWork (Oct 2, 2009)

Helmut said:


> The term grounding electrode is what you might be after.


No, because a "grounding electrode" is not what this thread is about. This thread is about rods only. All of the other types of grounding electrodes have different requirements.

LibertyRising, the inspector is correct, the house was not required to have 2 ground rods, and still isn't.


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## LibertyRising (Jan 2, 2018)

Actually he was incorrect, he told the homeowner we were not up to code because we left the one ground rod. Out of town inspections help due to disaster recovery.

I was doing some reading trying to figure out who the onus is on to prove that the ohms were within code. I’m thinking inspector because if he was going to fail it wouldn’t he have to prove it insufficient geound? Can he tell by looking at it? (No)

On the other hand would I have to be there at inspection time to prove it is?


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## HackWork (Oct 2, 2009)

360max said:


> 1978 nec


Not that simple.

1978 is when the requirement for a supplemental ground (in addition to the water pipe) was put in the NEC. That supplemental ground could be accomplished with many types of grounding electrodes, but it was most often done with rods. Using a second rod if not 25 Ohms was around for a long time, early 1900's I believe. But up until 2008 the inspector was the one who had to prove that it wasn't 25 Ohms. In the 2008 NEC they changed it so that the inspector could make the contractor prove it, or add a second rod.


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## flyboy (Jun 13, 2011)

LibertyRising said:


> Was it always 25ohms? I understand you can do either or, but was there a point in time where 200a services were sufficient with only 1 ground rod? When did the 2 ground rods *(or 25 ohms)* rule apply?





Bird dog said:


> Sounds more like you need to take some continuing education. :wink:


You redeemed yourself when re-asked the question with (or 25 ohms). In which case 360max would be correct - 1978

For those of you following my amazing career as the greatest and most handsome electrician in the Northeast, the 1978 NEC was the first code book I ever purchased. :vs_cool:


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## HackWork (Oct 2, 2009)

flyboy said:


> You redeemed yourself when re-asked the question with (or 25 ohms). In which case 360max would be correct - 1978
> 
> For those of you following my amazing career as the greatest and most handsome electrician in the Northeast, the 1978 NEC was the first code book I ever purchased. :vs_cool:


The 2008 NEC was the *only* code book I ever purchased. That foolish mistake won't be happening again.


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## LibertyRising (Jan 2, 2018)

Bird dog said:


> Sounds more like you need to take some continuing education. :wink:



I’ve bout decided that should be a year round thing or once or quarter type deal.


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## flyboy (Jun 13, 2011)

HackWork said:


> The 2008 NEC was the *only* code book I ever purchased. That foolish mistake won't be happening again.


And here I thought you were going to contest my greatest and most handsome electrician in the northeast claim.

You truly are my hero. :vs_love:


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## HackWork (Oct 2, 2009)

flyboy said:


> And here I thought you were going to contest my greatest and most handsome electrician in the northeast claim.
> 
> You truly are my hero. :vs_love:


I know sarcasm when I see it :biggrin:


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## LibertyRising (Jan 2, 2018)

Y’all haven’t even seen me yet


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## LibertyRising (Jan 2, 2018)

Y’all haven’t even seen me yet


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## paulengr (Oct 8, 2017)

The rule is one rod and under 25 ohms or drop a second one and NO limit on ohms. I have the expensive meter to test it but it takes longer to run the test than drop a rod if you have a demolition hammer to sink it.



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## frenchelectrican (Mar 15, 2007)

paulengr said:


> The rule is one rod and under 25 ohms or drop a second one and NO limit on ohms. I have the expensive meter to test it but it takes longer to run the test than drop a rod if you have a demolition hammer to sink it.
> 
> 
> 
> Sent from my iPhone using Tapatalk


Generally it cheaper and quicker to just drop a second rod than try to do the testing for proof of 25 ohms or less and the test is not same at most locations so the actual number will varies a bit.


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## paulengr (Oct 8, 2017)

The 25 ohm thing has been in there at least since the mid 90s that I remember. It’s actually really too high and the way it’s written it’s kind of a huge fail because you can just drop 2 ground rods and ignore it. MSHA requires annual testing but doesn’t set a limit at all but most mines use 25 ohms. IEEE 80 for substations recommends under 1 ohm as do most sensitive electronics standards. The IEEE and NFPA lightning standards require two paths to ground and inspections but no measurements.

Grounding science is easy but not well known. Grounding codes are just plain wacko.

If you really care about grounding get threaded rods and drive them one on top of the other. This gives you half the resistance of one rod. If you drive them side by side the second one should be at least one rod length away and it is only 70% as effective as the first. A third rod is only 30%. But if you stacked all three to make one long rod it’s 300% as effective as one rod. This is the reason that “triads” (I’m looking at you Duke and Dominion) are just plain idiotic and ineffective. As a bonus as you go deeper the water table is easier to reach.


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## LibertyRising (Jan 2, 2018)

In this case the house sits right on the river. If you post hole down 3.5’ you get water.


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## cwsims84 (Jan 21, 2012)

paulengr said:


> The 25 ohm thing has been in there at least since the mid 90s that I remember. It’s actually really too high and the way it’s written it’s kind of a huge fail because you can just drop 2 ground rods and ignore it. MSHA requires annual testing but doesn’t set a limit at all but most mines use 25 ohms. IEEE 80 for substations recommends under 1 ohm as do most sensitive electronics standards. The IEEE and NFPA lightning standards require two paths to ground and inspections but no measurements.
> 
> Grounding science is easy but not well known. Grounding codes are just plain wacko.
> 
> ...


That’s what we were doing while I was at the utility. Burndy makes that threaded coupler and then just let the Macho do the work! In one substation that was prob less than 10,000sqft, I bet we put 100 of those ****ers and 5ft centers for the 250kcmil ground grid.... they don’t take a whole of chances.


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## paulengr (Oct 8, 2017)

I don't do macho on ground rods any more. Just buy or rent a demolition hammer and an SDS ground rod adapter. You can drive rods effortlessly in under 5 minutes per rod unless you live in the mountains where you need a rock drill just to make the hole. If you really want fast and effective do a ufer. Dig a trench. Lay in ground rods. Backfill with concrete.

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## matt1124 (Aug 23, 2011)

When did code require 2̶ ̶g̶r̶o̶u̶n̶d̶ ̶r̶o̶d̶s both halves of a 10' ground rod on 200a service

FIFY


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## paulengr (Oct 8, 2017)

matt1124 said:


> When did code require 2̶ ̶g̶r̶o̶u̶n̶d̶ ̶r̶o̶d̶s both halves of a 10' ground rod on 200a service
> 
> FIFY




Read the thread. It doesn’t. But if your single rod (current doesn’t matter) tests over 25 ohms you need a second rod. After that it meets Code no matter what the resistance is. But the practical time to test vs. time to drive another rod means just drive two rods every time.


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## Southeast Power (Jan 18, 2009)

When I was starting out, every $1 was important. I was young and full of knowledge, always prepared to argue the 2 ground rod "rule" 
Now that Im old and have learned to choose my battles, every service gets 2 ground rods. But, the connections to them is still a #6 green or bare. I still have some principles about me. 

https://personalexcellence.co/blog/life-principles/

#75. Screw em'.


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## LibertyRising (Jan 2, 2018)

It wasn’t about the cost of it or saving a buck. We are doing flood repair jobs hundreds and hundreds of houses flooded, we have entire neighborhoods of jobs. Vast majority the entire services went under water, so speed running through on temporary power permits, replacing the services, getting some temp outlets for drying the house out, the grounding on most of these are just being reconnected since most of these houses are 90s and newer. Instructed my guys to just reconnect and run, and that one threw us for a loop. Now we are checking for 2 ground rods and adding the 2nd if not there. Would be nice if we could just operate on the assumption that if one passed when the house was built, that one would be good enough now, but whatever. 

Nearing the end of temp services list and now pricing rewires. The storm is a major boost in business, and teaching me to run a more efficient company. Averaging 25-40k a month for a 3 man shop, last month was 60. It’s fixing to go higher since we are only rewiring on fixed prices and the prices are going to reflect the pure shortage of manpower and the value of time when there’s not enough time to go around. 

Winning jobs priced x5 what id normally charge.


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## Southeast Power (Jan 18, 2009)

LibertyRising said:


> It wasn’t about the cost of it or saving a buck. We are doing flood repair jobs hundreds and hundreds of houses flooded, we have entire neighborhoods of jobs. Vast majority the entire services went under water, so speed running through on temporary power permits, replacing the services, getting some temp outlets for drying the house out, the grounding on most of these are just being reconnected since most of these houses are 90s and newer. Instructed my guys to just reconnect and run, and that one threw us for a loop. Now we are checking for 2 ground rods and adding the 2nd if not there. Would be nice if we could just operate on the assumption that if one passed when the house was built, that one would be good enough now, but whatever.
> 
> Nearing the end of temp services list and now pricing rewires. The storm is a major boost in business, and teaching me to run a more efficient company. Averaging 25-40k a month for a 3 man shop, last month was 60. It’s fixing to go higher since we are only rewiring on fixed prices and the prices are going to reflect the pure shortage of manpower and the value of time when there’s not enough time to go around.
> 
> Winning jobs priced x5 what id normally charge.


I think you are going to find out that your 3 man shop can and should be bringing in 20k per week if you have a constant feed of good business.
You are providing a premium service that commands a premium price. 
DO NOT SQUANDER THIS OPPORTUNITY!!


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## LibertyRising (Jan 2, 2018)

Southeast Power said:


> I think you are going to find out that your 3 man shop can and should be bringing in 20k per week if you have a constant feed of good business.
> You are providing a premium service that commands a premium price.
> DO NOT SQUANDER THIS OPPORTUNITY!!


When i first read that, I admit that I thought that was lofty.. But after crunching that goal vs what we actually have lined up, it’s entirely possible we got that this week. Exciting!


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## paulengr (Oct 8, 2017)

There are 2 legitimate ways to test ground rods:

1. Use the 3 point method where you stick a couple stakes in the ground and run wire to 
them and use a 3 point ground tester. This is the most accurate way but by the time you set everything up and get readings, you already had plenty of time to drive that second ground rod and connect it.
2. Use a clamp on ground rod tester. This takes seconds to do EXCEPT that it only works when you have multiple ground rods. If you only have one you'd have to drive either a second temporary or permanent one and then test. I have one of these. I use it on building grounding systems which by Code are always supposed to have at least 2 connections to Earth.

If you are already doing 2 rods, get a clamp on tester. It takes seconds to do the test and if it measures over 25 ohms you can explain to the customer that they have a bad ground rod and use it to generate more business on something as simple and cheap as driving more ground rods.


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## HackWork (Oct 2, 2009)

paulengr said:


> If you are already doing 2 rods, get a clamp on tester. It takes seconds to do the test and if it measures over 25 ohms you can explain to the customer that they have a bad ground rod and use it to generate more business on something as simple and cheap as driving more ground rods.


Anyone who upsells a residential customer on more than 2 ground rods should be kicked in the taco.


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## riverman (Feb 6, 2019)

In Kentucky we started driving two ground rods in 1996 I think it was a state wide ruling.


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## drsparky (Nov 13, 2008)

paulengr said:


> There are 2 legitimate ways to test ground rods:
> 
> 1. Use the 3 point method where you stick a couple stakes in the ground and run wire to
> them and use a 3 point ground tester. This is the most accurate way but by the time you set everything up and get readings, you already had plenty of time to drive that second ground rod and connect it.
> ...


All tests must be done before the neutral is connected to the utility.


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## lighterup (Jun 14, 2013)

paulengr said:


> I don't do macho on ground rods any more. Just buy or rent a demolition hammer and an SDS ground rod adapter. You can drive rods effortlessly in under 5 minutes per rod unless you live in the mountains where you need a rock drill just to make the hole. If you really want fast and effective do a ufer. Dig a trench. Lay in ground rods. Backfill with concrete.
> 
> Sent from my SM-T350 using Tapatalk


Assuming one is in rocky terrain , do you think drilling
thru rock or bedrock like we have around the Great Lakes 
will provide a worthwhile ground?

It seems to me it would not.


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## MTW (Aug 28, 2013)

HackWork said:


> The 2008 NEC was the *only* code book I ever purchased. That foolish mistake won't be happening again.


How do you look up the code then? Online?


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## MTW (Aug 28, 2013)

HackWork said:


> Anyone who upsells a residential customer on more than 1 ground rod should be kicked in the taco.



Fify


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## brian john (Mar 11, 2007)

drsparky said:


> All tests must be done before the neutral is connected to the utility.


Or Isolated


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## HackWork (Oct 2, 2009)

MTW said:


> How do you look up the code then? Online?


PDF. Looking up code is much easier when you could just search for a word or phrase.


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## MTW (Aug 28, 2013)

HackWork said:


> PDF. Looking up code is much easier when you could just search for a word or phrase.


Thanks. The code book is a total scam. All you need to know are the pertinent changes which don't change much for resi anyway.


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## manchestersparky (Mar 25, 2007)

If the house has Metallic water lines that are 10' in contact with earth you hit that within 5' of where it enters then drop 1 rod and bam your done

NOW if you only grounding electrode is a rod then yes 2 are or 25 ohms or less come into play


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## HackWork (Oct 2, 2009)

manchestersparky said:


> If the house has Metallic water lines that are 10' in contact with earth you hit that within 5' of where it enters then drop 1 rod and bam your done
> 
> NOW if you only grounding electrode is a rod then yes 2 are or 25 ohms or less come into play


That might be a local amendment, but not the NEC.

Even if you use the water pipe as a grounding electrode, when using a ground rod as a supplemental electrode you need to either prove 25ohms or use 2 rods.


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## scotch (Oct 17, 2013)

Years ago one of the inspectors used to have a old style screw in fuse unit and would require us to temp wire into a 15a breaker with a 5A fuse in the unit to prove grounding .......fun times!


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