One GEC to all electrodes

Status
Not open for further replies.
jaylectricity

jaylectricity

Senior Member
Location
Massachusetts
Occupation
licensed journeyman electrician
I have a situation where I've driven two ground rods into the garden on the other side of the basement wall where the water main comes into the basement .

It's not a cement wall, the foundation actually stops a few feet above the basement floor, and maybe six inches above grade outside the wall.

Can I just run a single GEC from the meter/main through the basement to the water grounds (one clamp on each side of the meter) then continue on through the wall to hit each of the ground rods?

Keep in mind that here in MA we usually run the ground rod GEC to the meter socket and the water ground to the panel with the main breaker. But in this case the main breaker is in the meter socket, so both would run to that.

My concern is that each of the electrode systems need their own GEC to bond to the service grounded conductor.
 
You only have one grounding electrode conductor. The other wire is a bonding conductor. The wire going to the water pipe probably has to be larger than the one going to the rods so let's call that the grounding electrode conductor and then the smaller wire going to the rods is the bonding conductor

I am not entirely sure that what you are saying that you do in Massachusetts is even code compliant.
 
It's a 100 amp service, so both conductors are #6.

As far as code compliance goes, what code would I be violating by bringing a #6 from the ground rods to the meter socket outside and then bringing a #6 from the water main to the circuit panel inside where the main OCD is located?
 
jaylectricity said:
It's a 100 amp service, so both conductors are #6.

As far as code compliance goes, what code would I be violating by bringing a #6 from the ground rods to the meter socket outside and then bringing a #6 from the water main to the circuit panel inside where the main OCD is located?
Click to expand...


That's how I do it all the time (100 amp).

Except I usually use #4 to the meter so I don't have to protect it.

200 amp they're both #4.
 
jaylectricity said:
It's a 100 amp service, so both conductors are #6.

As far as code compliance goes, what code would I be violating by bringing a #6 from the ground rods to the meter socket outside and then bringing a #6 from the water main to the circuit panel inside where the main OCD is located?
Click to expand...

If each wire is a home run from an electrode to the same point, they would IMHO both be GECs.

If a wire extended from one electrode to another it would be a bonding jumper.

But if you have two home runs going to two different nearby but different points would one of them be a jumper?
Is there anything in the NEC to argue that they have to terminate in the same place?
 
So there are four points on this grounding electrode system. There is a water ground clamp on either side of the water meter and two ground rods. Is there any difference between having a properly sized GEC hit each point with a continuous conductor and having separate conductors from each point bond at the service neutral?
 
jaylectricity said:
...
Can I just run a single GEC from the meter/main through the basement to the water grounds (one clamp on each side of the meter) then continue on through the wall to hit each of the ground rods?
...
Click to expand...
Yes. In fact, Code makes it seem like you only have the option to run one GEC. Note some POCO's require a ground rod GEC to land in the meter can... so that's where one end may have to terminate if your POCO requires that.
 
Well I think that's what our POCOs require because I have terminated the GEC from the ground rod into the meter socket 100% of the times I've installed/replaced/upgraded a service.
 
jaylectricity said:
So there are four points on this grounding electrode system. There is a water ground clamp on either side of the water meter and two ground rods. Is there any difference between having a properly sized GEC hit each point with a continuous conductor and having separate conductors from each point bond at the service neutral?
Click to expand...

There is a difference, but I agree with your likely point that the Code does not care. :)
The other variation is to have several termination points for ground runs.
 
Smart $ said:
Yes. In fact, Code makes it seem like you only have the option to run one GEC. Note some POCO's require a ground rod GEC to land in the meter can... so that's where one end may have to terminate if your POCO requires that.
Click to expand...

But is it or is it not OK to land the conductors (whatever you call them) from other electrodes somewhere else?
Probably. Otherwise auxiliary grounds for special equipment connected to building steel for the return path would be problematic.
 
The code strongly implies that all the grounding electrode connections have to run through a single point. It doesn't exactly make it explicit, although I believe it would be better if it did.

Every reference in 250 is to 'the' grounding electrode conductor. 250.50 also says that all the electrodes have to be bonded together to form an system. Combine that with 250.6 (Objectionable current), and logically you are not allowed to run different GECs to different places where you bond to the service neutral, because in meeting the requirement to bond the electrodes all together you'd be creating a parallel path for objectionable neutral current.

(Note: this does not include auxiliary electrodes, which I believe you should never install so long as you can avoid losing an argument with a misinformed person.)

I admit to stretching the principle sometimes and bringing multiple conductors from electrodes into the main service panel. But always to that same location. What's difference if I bring two or three conductors into a panel vs connecting the 'bonding jumpers' together a few inches outside the panel? Not much I think. And I'm not creating a ground loop or a path for objectionable current.

With regard to multiple disconnecting means: you're allowed to run taps to 'the' GEC. But it's strongly implied that you have to run the taps to one GEC ('the' GEC), and that one GEC runs to the GES where the bonding jumpers can branch out to the electrodes.

When I run into places where the GEC is terminated in the meter socket then I connect any new electrodes to that GEC.
 
GoldDigger said:
But is it or is it not OK to land the conductors (whatever you call them) from other electrodes somewhere else?
Probably. Otherwise auxiliary grounds for special equipment connected to building steel for the return path would be problematic.
Click to expand...
Code says you can connect 'the' GEC to the grounded conductor anywhere from the service point to disconnecting means... which does not include an auxiliary grounding electrode conductor because it connects to an EGC. Building steel cannot be used as an intentional return path, but is quite often as an inadvertent return path.
 
jaggedben said:
The code strongly implies that all the grounding electrode connections have to run through a single point. ...
Click to expand...
It is not that the GEC's/Grounded be connected at one point but rather the EGS/Grounded be connected at one point. The GES is a close second though because it is essentially limited to the service entrance grounded conductor(s).
 
Smart $ said:
It is not that the GEC's/Grounded be connected at one point but rather the EGS/Grounded be connected at one point. The GES is a close second though because it is essentially limited to the service entrance grounded conductor(s).
Click to expand...

I stand by what I said above. If you connect two GECs to the grounded conductor at different points and then bond the electrodes to each other you've violated 250.6. If you don't bond the electrodes you've violated 205.50. I guess you could get away with the first one if it's a detached building GES that's only connected to the EGS and not the grounded conductor. I
 
jaggedben said:
I stand by what I said above. If you connect two GECs to the grounded conductor at different points and then bond the electrodes to each other you've violated 250.6. If you don't bond the electrodes you've violated 205.50. I guess you could get away with the first one if it's a detached building GES that's only connected to the EGS and not the grounded conductor. I
Click to expand...
As I said, it's about connecting the equipment grounding system to the grounded conductor at one point that is most significant (MBJ/SBJ). A GEC/GES can be connected at several specific points along distribution routing, from the service entrance grounded conductor, to separately derived systems, to a feeder EGC at a detached building, to any branch circuit EGC as an auxiliary grounding electrode.

But you are correct about bonding the same GES at two different points on the grounded conductor. But if you follow the rules, that can only happen on the service entrance conductor. As a matter of fact, it happens all the time and is considered by many as compliant... even taking 250.6 into account.
 
jaylectricity said:
I have a situation where I've driven two ground rods into the garden on the other side of the basement wall where the water main comes into the basement .

It's not a cement wall, the foundation actually stops a few feet above the basement floor, and maybe six inches above grade outside the wall.

Can I just run a single GEC from the meter/main through the basement to the water grounds (one clamp on each side of the meter) then continue on through the wall to hit each of the ground rods?

Keep in mind that here in MA we usually run the ground rod GEC to the meter socket and the water ground to the panel with the main breaker. But in this case the main breaker is in the meter socket, so both would run to that.

My concern is that each of the electrode systems need their own GEC to bond to the service grounded conductor.
Click to expand...
I think the way you usually do it is how it should be done. Your ground rods aren't really doing anything, are they? If you lose the ground before the meter you have nothing.
 
Smart $ said:
But you are correct about bonding the same GES at two different points on the grounded conductor. But if you follow the rules, that can only happen on the service entrance conductor. As a matter of fact, it happens all the time and is considered by many as compliant... even taking 250.6 into account.
Click to expand...

Well, for people who consider that to not be a violation of 250.6 I will just reiterate my disagreement. (Mind you, I know that sometimes there is objectionable current on water pipes between houses, but that's something people don't really have knowledge or control of if they comply with using the water pipe as an electrode, so it is what it is.)

If you're complying with 250.50, there's generally no reason to run multiple GECs, especially with a single service disconnecting means.

Here's my concise response to the OP's post:

Can I just run a single GEC from the meter/main through the basement to the water grounds (one clamp on each side of the meter) then continue on through the wall to hit each of the ground rods?
Click to expand...

Not only can you, but you should. You're more likely violating code and good grounding practices if you do it some other way.
 
Status
Not open for further replies.
Top