Is this legal?

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joeyww12000

joeyww12000

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Chatsworth GA
Good morning, I posted a question yesterday about bringing GEC's out of a MDP enclosure. The GEC's would come off the EGC bonding point at the enclosure of the MDP. The MDP is bonded by the EGC coming from the service disconnect where the grounded/neutral conductor is bonded. Here is a sketch.
 
Is this legal?

joeyww12000 said:
Good morning, I posted a question yesterday about bringing GEC's out of a MDP enclosure. The GEC's would come off the EGC bonding point at the enclosure of the MDP. The MDP is bonded by the EGC coming from the service disconnect where the grounded/neutral conductor is bonded. Here is a sketch.
Click to expand...

Is the MDP in a separate building? If it is it looks ok to me. You may need 2 grd rods at the Main disconnect.
 
Correct terminology (and sizing) can make a big difference :grin:

gecsystem.gif
 
buddhakii said:
I see nothing wrong with this, but the op doesn't show the gec going from MDP to the service disco. It shows a line going outside of the MDP to nowhere.
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OP's sketch shows two lines between SD and MDP. One is the Neutral. The other he calls an EGC. Such an installation is non-compliant. The one he calls an EGC (sized per 250.122 ?) needs to be a GEC (sized per 250.66, along with other req'ts) for the installation to be compliant.
 
Smart $ said:
OP's sketch shows two lines between SD and MDP. One is the Neutral. The other he calls an EGC. Such an installation is non-compliant. The one he calls an EGC (sized per 250.122 ?) needs to be a GEC (sized per 250.66, along with other req'ts) for the installation to be compliant.
Click to expand...

I clicked on the thumbnail and it cuts off the other line, but know that I look closely at the thumbnail I can see the second line going all the way to the SD.
 
sorry about the sketch guys.....I know it cut off in places....all Im really wanting to know is do all GEC's when ran to seperate electrodes individually need to run all the way back to the first disconnect where the neutral/grounded conductor bond is made.......the problem is the wire is pulled from the Disconnect into the MDP already.......if the wire used as a ground is sized according to 250.66 from the Disconnect to the MDP can the other GEC's be brought into the MDP instead? What is the code section for this if you can...thanks
 
Ok......noone can really give a definative answer...everyone has his own opinion.....which is OK, I would just like to see code for taking a GEC to anywhere other than the first means of disconnect.
 
joeyww12000 said:
Ok......noone can really give a definative answer...everyone has his own opinion.....which is OK, I would just like to see code for taking a GEC to anywhere other than the first means of disconnect.
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You are not going to find that, the GEC shall be connected to the grounded service conductor

on the supply side of the service disconnecting means.

Also, A gec or an egc can not serve two purposes, it's either a GEC or an EGC but not both.

What you could do is at the MDP take all the GEC out of it and land them on a bus bar

from the bus bar take a 250.66 sized GEC to the service disconnect,that's 250.64(F)(3)

as mentioned by previous poster.
 
benaround said:
A gec or an egc can not serve two purposes, it's either a GEC or an EGC but not both.

What you could do is at the MDP take all the GEC out of it and land them on a bus bar from the bus bar take a 250.66 sized GEC to the service disconnect,that's 250.64(F)(3) as mentioned by previous poster.
Click to expand...

Please cite reference for 1) a conductor sized per 250.66 cannot serve as both a GEC and an EGC, and 2) where a busbar or other forms of GEC connections must be separate from energized equipment.
 
this happens to be a service I did not do.....the foreman on my job at first allowed a neutral/grounded conductor bond at the disconnect and one at the MDP.........all the EGC's from panels fed from the MDP where tied to neutral bus in the MDP.......Ive got him to change some of these mistakes, but the grounding electrodes...steel and waterpipe remain bonded and terminated inside the MDP to the Neutral bus....I told him to make this safe I would at the least connect them to the EGC ground bar......actually though I think they should go to the outside disconnect but the wire is pulled and it would be hard to get them there...
 
benaround said:
Also, A gec or an egc can not serve two purposes, it's either a GEC or an EGC but not both.
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I'm not trying to argue.
It's just that reading this thread has raised a few questions in my mind.
You say that a EGC can not serve two purposes.

If I, for example, run a (4 wire single phase) feeder from a Main Disconnect to a panel located in another building, drive two ground rods at the seperate building and bond them (in the remote panel) to the equipment grounding conductor that's run with the feeder.

Assume that the Grounded conductor (neutral) in the feeder is properly conected. This is a "standard" (for me) feeder installation to a remote panel in a seperate structure.

Is the grounding conductor between the panels acting as a equipment grounding conductor (EGC) , or is it a Grounding Electrode Conductor (GEC)?

It seems to me that it's acting as both a EGC and A GEC.

Is this Feeder Grounding Conductor sized per 250.66 or 250.122?

steve
 
steve, The EGC in your feeder is just that, an EGC, it is the path back to the source to

ensure ths OCPD will get enough current to trip. The two ground rods at the 2nd building

connect to the EG bus ( not the neutral ) and they are grounding electrodes. So the two

conductors EGC and the GEC both only serve one function.

Almost forgot, the EGC with the feeders is sized from 250.122
 
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benaround said:
...

So the two conductors EGC and the GEC both only serve one function.

...
Click to expand...
I do not dispute the dubbing of these conductors. However, to say they serve only one function is to say each is selective of the current they carry. I don't believe them to be that smart :rolleyes::grin:

For example, upon a lightning surge on the supply system, when current passes through the service Grounding Electrode System to earth, current also passes through the EGC of the feeder and the Grounding Electrode System at the remote structure. Under this condtion, the feeder's EGC is serving the function of a GEC. To believe otherwise is to not have a full understanding of how electricity functions.
 
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Smart,

That same lightning event may jump to a metal drain pipe while its at it, but, I would not

call the metal drain pipe a grounding electrode. I do agree with your lightning path, but, I

do not think that it was designed for that purpose, any more than the drain pipe. JMO.

For the record, it was one of the respected members of this Forum that posted the

comment about EGC and GEC are seperate items and I just passed it on from there. I am

just an Electrician as far as my knowledge goes.
 
joeyww12000 said:
Ok......noone can really give a definative answer...everyone has his own opinion.....which is OK, I would just like to see code for taking a GEC to anywhere other than the first means of disconnect.
Click to expand...
See 250.24(A)(1) I would buying the 2008 Handbook and looking at page 206, Exhibit 250.8. The grounded service conductor can be connected to the gec at only one of three places:
1. Load end of service drop
2. In accessible meter enclosure(our utility co. in Phila. won't allow this)
3. In service disconnecting means
 
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