GEC

[binwork91]

I know that most of the time, we run the GEC from the service switch to the grounding collector bus.

I’d like to confirm whether the following scenarios constitute code violations. If so, please let me know the applicable code sections. Thank you.

1. Running the GEC along with the phase conductors and neutral from the SEB to the service switch, and then a single GEC from the service switch to the grounding collector bus.

For example: (1) 600 MCM Cu per phase and neutral with (1) 1/0 Cu GEC in a 4" conduit from the SEB to a 400A service switch. Then, a separate 1/0 Cu GEC runs from the 400A service switch to the grounding collector bus.

Question: Would it be a violation to run the 1/0 Cu GEC in the same conduit as the service conductors?

2. In another case, I have a 4000A service switchboard. From this switchboard, I run a 3/0 Cu GEC to the grounding collector bus. Then, a tap section in the switchboard feeds a 400A service switch using (1) 600 MCM Cu per phase and neutral with a 1/0 Cu GEC in a 4" conduit. The 1/0 Cu GEC is connected to the ground bus inside the 4000A switchboard. There is no additional GEC from the 400A service switch to the grounding collector bus.

Question: Is this setup acceptable per code?

3. Same scenario as Question 2, but with an additional 1/0 Cu GEC run from the 400A service switch to the grounding collector bus.

Question: Would this be code-compliant as well?

 

[don_resqcapt19]

What is a SEB?

 

[binwork91]

What is a SEB?

Service End (copper detail) Box.

 

[don_resqcapt19]

Service End (copper detail) Box.

Still no idea of what that is

 

[wwhitney]

Still no idea of what that is

Pretty sure it's an underground enclosure that contains the service point. Which should suffice for this discussion.

Cheers, Wayne

 

[zbang]

I think it's a NYC ConEd thing- the box where the PoCo service conductors connect to the customer-owned service conductors. IIRC there have been some photos of them on the forums in the last year.

 

[tom baker]

What is the grounding collector bus, or what connects to it? Or is it what the NEC calls a grounding busbar?

 

[infinity]

For example: (1) 600 MCM Cu per phase and neutral with (1) 1/0 Cu GEC in a 4" conduit from the SEB to a 400A service switch. Then, a separate 1/0 Cu GEC runs from the 400A service switch to the grounding collector bus.

The #1/0 from the end box is not required and is a violation. The GEC run to the service disconnect is code compliant.

Then, a tap section in the switchboard feeds a 400A service switch using (1) 600 MCM Cu per phase and neutral with a 1/0 Cu GEC in a 4" conduit

The 400 amp switch is a service disconnect so there is not a GEC (I believe you meant EGC) run with the "tap" conductors and the #1/0 GEC must be removed. If a GEC lands upstream of the "tap" connection then no GEC is required at the 400 amp service disconnect.

 

[binwork91]

The #1/0 from the end box is not required and is a violation. The GEC run to the service disconnect is code compliant.

Can you tell the code section?

The 400 amp switch is a service disconnect so there is not a GEC (I believe you meant EGC)

From switchboard to 400A service disconnect, it is service conductor. So ground conductor is GEC. it is on the line side of service switch.

If a GEC lands upstream of the "tap" connection then no GEC is required at the 400 amp service disconnect.

Do you mean the 400A service switch does not need a GEC, since switchboard's GEC is at the upstream of 400A service switch?

 

[binwork91]

Still no idea of what that is

It is a box with a copper bus where the utility cable is terminated.

What is the grounding collector bus,

It is a piece of copper bus that connects GECs from service switches and the GEC to the ground rod.

 

[infinity]

Can you tell the code section?

250.6(B).

From switchboard to 400A service disconnect, it is service conductor. So ground conductor is GEC. it is on the line side of service switch.

There is no "ground" run with the service conductors. For one this would be in parallel with the neutral so you'll end up with a 600 kcmil and a #1/0 in parallel. You've stated that the 400 amp switch will have a separate GEC correct? If so then there is no "ground" on the line side of the service disconnect.

Do you mean the 400A service switch does not need a GEC, since switchboard's GEC is at the upstream of 400A service switch?

Correct. The GEC can connect at any point between the service disconnect and the service point which is the end box. If there is a GEC connected ahead of the point where the "tap" conductors for the 400 amp switch connect then even though the 400 amp switch is a servcie disconnect it does not require its own GEC.

Here's an example of how it can be done. The GEC connects at a point ahead of the "taps" only one is required for all of the service disconnects.

 

[infinity]

It is a box with a copper bus where the utility cable is terminated.

ConEd end box with current limiters at the service point:

It is a piece of copper bus that connects GEC's from service switches and the GEC to the ground rod.

Ground bus:

 

[binwork91]

Correct. The GEC can connect at any point between the service disconnect and the service point which is the end box. If there is a GEC connected ahead of the point where the "tap" conductors for the 400 amp switch connect then even though the 400 amp switch is a servcie disconnect it does not require its own GEC.

Is it acceptable to install a GEC at every piece of equipment located on the line side of the service disconnect?
If yes, does each piece of equipment with a GEC need to have the neutral bonded to ground.

 

[infinity]

Is it acceptable to install a GEC at every piece of equipment located on the line side of the service disconnect?
If yes, does each piece of equipment with a GEC need to have the neutral bonded to ground.

Yes you can run a GEC to each piece of equipment but there is little reason to do so. All metal parts on the line side of the service disconnect(s) get bonded to the neutral. A single GEC or bonding jumper from your external ground bus is all that is required if it terminates upstream of the servcie disconnect(s).

250.24(A)(1) General.
The grounding electrode conductor connection shall be made at any accessible point from the load end of the overhead service conductors, service drop, underground service conductors, or service lateral to, including the terminal or bus to which the grounded service conductor is connected at the service disconnecting means.

 

[binwork91]

All metal parts on the line side of the service disconnect(s) get bonded to the neutral.

I am kinda confuse for following question, if you can answer it one more time. thank you.

Can you run a grounding conductor along with the service phase and neutral conductors in a conduit on the line side of the service switch?

If yes, is it sized per NEC 250.66 as a GEC?

If no, then I’m a bit confused about the following two scenarios:

1. A tap section in the switchboard feeds a 400A service switch using one 600 MCM copper conductor per phase and neutral, along with a 1/0 copper ground conductor (GEC) in a 4" conduit. The 1/0 Cu GEC is connected to the ground bus inside the 4000A switchboard. You mention it is violation per 250.6 Objection current.

2. Similar to scenario 1, but there is no 1/0 copper grounding conductor in the 4" conduit. Instead, the 4" conduit is bonded to both the upstream switchboard and the 400A service disconnect. Both pieces of equipment have their ground, neutral, and enclosure bonded together. I think that is how it install for the equipment. if i am wrong, please let me know.

Does the bonded conduit serve the same function as the 1/0 copper grounding conductor in scenario 1?"

I just no sure if 250.6 is a right section to answer this question.

 

[roger]

Can you run a grounding conductor along with the service phase and neutral conductors in a conduit on the line side of the service switch?

You will only have phase conductors and a neutral on the line side of the service, there is no EGC or GEC run with them

1. A tap section in the switchboard feeds a 400A service switch using one 600 MCM copper conductor per phase and neutral, along with a 1/0 copper ground conductor (GEC) in a 4" conduit. The 1/0 Cu GEC is connected to the ground bus inside the 4000A switchboard. You mention it is violation per 250.6 Objection current.

That is a feeder, not service conductors, you're talking about an EGC.

2. Similar to scenario 1, but there is no 1/0 copper grounding conductor in the 4" conduit. Instead, the 4" conduit is bonded to both the upstream switchboard and the 400A service disconnect. Both pieces of equipment have their ground, neutral, and enclosure bonded together. I think that is how it install for the equipment. if i am wrong, please let me know.

That is incorrect, after the service equipment the EGC and neutral are separated

Does the bonded conduit serve the same function as the 1/0 copper grounding conductor in scenario 1?"

Yes

I just no sure if 250.6 is a right section to answer this question.

Connecting the EGC and Neutral downstream of the service puts the two in parallel

 

[binwork91]

You will only have phase conductors and a neutral on the line side of the service, there is no EGC or GEC run with them

Can you tell me the code section about this? I have a contractor install the Ground with service conductor. That is why I am try to find out the answer and code to ask him to remove the ground.

That is a feeder, not service conductors, you're talking about an EGC.

It is service conductor. The 400A switch is service switch. same idea as 400A switch in the picture post at #11.
There is not service disconnect ahead of 400A switch.

 

[infinity]

Can you run a grounding conductor along with the service phase and neutral conductors in a conduit on the line side of the service switch?

No. As Roger said there are no EGC's ahead of the service disconnect. For clarity try to use the proper terminology because it may change the answer to your question if we misinterpret a phrase like grounding conductor. If you do run an EGC along with the servcie conductors it will be in parallel with the neutral which is a violation. Technically an EGC cannot start until after the point where the MBJ is installed.

It is service conductor. The 400A switch is service switch. same idea as 400A switch in the picture post at #11.
There is not service disconnect ahead of 400A switch.

I agree these are service conductors as mentioned the 400 amp service disconnect switch is fed by a "tap" from the service. Tap is in quotes because although this is commonly called a tap these are not tap conductors.

 

[roger]

It is service conductor. The 400A switch is service switch. same idea as 400A switch in the picture post at #11.
There is not service disconnect ahead of 400A switch.

I agree these are service conductors as mentioned the 400 amp service disconnect switch is fed by a "tap" from the service. Tap is in quotes because although this is commonly called a tap these are not tap conductors.

I see now and that would mean the Neutral would also function as an EGC, there would not be a separate wire type conductor. As Rob said, a MBJ would be required.

 

[binwork91]

For clarity try to use the proper terminology because it may change the answer to your question if we misinterpret a phrase like grounding conductor.

Sorry about this. I thought the EGC was the grounding conductor after the service disconnect.

The GEC is the grounding conductor ahead of the service disconnect. I think I was wrong about the GEC.

So, what is the correct name for the grounding conductor that runs along with the service conductors? Is it the EGC?

If you do run an EGC along with the servcie conductors it will be in parallel with the neutral which is a violation. Technically an EGC cannot start until after the point where the MBJ is installed.

Can you tell me the code section about this? That is the answer i try to find out.