ground rods needed at sub panel ?

[infinity]

Sounds like someone thought that the EGC could not be run directly buried in the ground. Can't a bare copper EGC be run in the trench?

 

[roger]

Thank you, I see that. What about 300.5 (I, the section after section H) Exception No. 1 ? Does this allow what they have done ? Direct burial conductor shall be...in close proximity in the trench...including EGCs. ?

No, that section is for parallel installations and each raceway will contain the following.

Each raceway or multiconductor cable shall contain all conductors of the
same circuit, including equipment grounding conductors.

Exception No. 2 would be closer but once again that is for parallel installations.

 

[Stevenfyeager]

That is why I asked if the conduit was a complete raceway or just a sleeve. Being in the same trench but also in an individual conduit is not something that I would have ever imagined having to consider. Electrically it may work fine but it's such a weird installation that I wouldn't trust any of other work done by someone who would do such a thing.

right, I'm not sure why they did it that way, I've never seen that. The trench work is the only thing they've done. The are asking me to do the rest, like connecting both ends of the buried lines in the disconnect combo and in the barn panel, running inside barn circuits etc. I guess I''ll have my book open to 300.5 I Exception 1 when I buy a permit and get it inspected and see what the inspector says. I will drive two more ground rods at the barn too. Thanks.

 

[roger]

right, I'm not sure why they did it that way, I've never seen that. The trench work is the only thing they've done. The are asking me to do the rest, like connecting both ends of the buried lines in the disconnect combo and in the barn panel, running inside barn circuits etc. I guess I''ll have my book open to 300.5 I Exception 1 when I buy a permit and get it inspected and see what the inspector says. I will drive two more ground rods at the barn too. Thanks.

Did you read through the exception?

Exception No. 1: Conductors shall be permitted to be installed
in parallel in raceways, multiconductor cables, or
direct-buried single conductor cables. Each raceway or
multiconductor cable shall contain all conductors of the
same circuit, including equipment grounding conductors.
Each direct-buried single conductor cable shall be located
in close proximity in the trench to the other single conductor
cables in the same parallel set of conductors in the
circuit, including equipment grounding conductors.

 

[roger]

By all rights and common sense it would be fine but per the words of the code it isn't.

 

[Stevenfyeager]

By all rights and common sense it would be fine but per the words of the code it isn't.

I see what you all mean. The ‘ close proximity in trench including grounding conductor’ phrase is for a parallel case. The inspector could require them to re do the trench work.

 

[roger]

I see what you all mean. The ‘ close proximity in trench including grounding conductor’ phrase is for a parallel case. The inspector could require them to re do the trench work.

Hopefully not but he could if he wanted to.

 

[Stevenfyeager]

Inspector said the grounding was fine between the two panels. I asked him if I should install 2 grd rods at the meter pedestal beside the utility pole and two rods at the barn. He said, no : "one rod at each location" He also made sure the meter is in sight of the barn, otherwise I would have needed another outside disconnect on the barn.

 

[Srv52761]

A customer has installed a 200 amp meter - disconnect combo at a utility pole and then trenched to a barn with a 200 amp sub panel. They installed ground rods at the pedestal but not at the barn. Not sure of the distance, will look this week. 2 rods are needed at both locations, correct ?
At a different job I did for a mobile home customer, the inspector only required 2 rods at the disconnect pedestal but not at the m home. But the underground distance was only 5'. So, is it a distance factor ? Thanks

I believe if it is a separate structure it needs ground rods. But, I don’t believe it needs its own ground rods. Five feet seems close enough (depending on where the sub panel is in relation to the pedestal) to tie into the pedestal ground system.

Benn a long time since I read that part, so I could be wrong.

 

[don_resqcapt19]

Assuming that the EGC is in PCV and in the same trench, it is my opinion that 300.3(B)(3) acts as an exception to 300.3(B) and permits the installation.

 

[kevin.luce@matsuk12.us]

So to add to this conversation, is the EGC required for direct burial installations to separate building? The separate building requires it own ground rod seemingly negating the need for a EGC from the source panel to the building disconnect. I was taught to run a ground and have never looked back till yesterday when I was told it was not needed. The AJH is in agreement that it is not needed only if the feeders are in a raceway. Can someone tell me where in NEC this would be located? I will keep looking myself.

 

[Dennis Alwon]

So to add to this conversation, is the EGC required for direct burial installations to separate building? The separate building requires it own ground rod seemingly negating the need for a EGC from the source panel to the building disconnect. I was taught to run a ground and have never looked back till yesterday when I was told it was not needed. The AJH is in agreement that it is not needed only if the feeders are in a raceway. Can someone tell me where in NEC this would be located? I will keep looking myself.

Yes it is necessary to have an equipment grounding conductor. The ground rod is not a replacement for the equipment grounding conductor as the rod is mostly there for protection from lightning and surges.

 

[infinity]

So to add to this conversation, is the EGC required for direct burial installations to separate building?

Yes and it is also required if the feeder is in a raceway or overhead.

The separate building requires it own ground rod seemingly negating the need for a EGC from the source panel to the building disconnect.

It requires a GES, a ground rod can be one of the electrodes making up the GES but it isn't the only option. A new structure may have rebar in the footing which if it qualifies as a CEE it's use would be mandatory. Both the GES and the EGC are required.

 

[wwhitney]

The AJH is in agreement that it is not needed only if the feeders are in a raceway.

If the feeders are in a metallic raceway, it could be the EGC, so a wire-type EGC would not be required. But an EGC is always required.

Cheers, Wayne

 

[kevin.luce@matsuk12.us]

Thank you for the input. It has always been my understanding and EGC was required. To further this conversation is there any NEC exception listed disallowing the need for a EGC in any circumstance? The AHJ says a separate grounding electrode system will be installed at each building. Further stating this is NEC compliant and a cost effective way to feed separate building. These are direct burial conductors with no raceway connecting the two structures.

 

[roger]

Each detached building must have a GES and an EGC, they are doing separate jobs. The GES at a detached building will not connect to the grounded conductor as they do at the service, it will only connect to the EGC.

 

[LarryFine]

So to add to this conversation, is the EGC required for direct burial installations to separate building?

Absolutely, yes, with any circuit or feeder.

The separate building requires it own ground rod seemingly negating the need for a EGC from the source panel to the building disconnect.

Absolutely not. The earth alone will not conduct well enough to trip an OCPD.

I was taught to run a ground and have never looked back till yesterday when I was told it was not needed. The AJH is in agreement that it is not needed only if the feeders are in a raceway.

An EGC must be run. A metallic conduit can suffice as the EGC, but won''t last forever underground.

Can someone tell me where in NEC this would be located? I will keep looking myself.

Art. 250, of course.

 

[LarryFine]

To further this conversation is there any NEC exception listed disallowing the need for a EGC in any circumstance?

Only in the past, for existing feeders, and with no other well-bonded pathways (like metal water pipe) in parallel.

Back then, the neutral also provided a pathway for OCPD operation from fault currents, like with a 3-wire service.

 

[electrofelon]

Only in the past, for existing feeders, and with no other well-bonded pathways (like metal water pipe) in parallel.

Back then, the neutral also provided a pathway for OCPD operation from fault currents, like with a 3-wire service.

Actually we are still allowed to use the neutral (grounded conductor) as the EGC for outdoor separate derived systems.