Grounding a 600 amp service

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Hawkins

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I am installing a 600 amp single phase service for a customer. The poco has the CT and meter on the pole and the a 600 amp disconnect is located on the outside of the building, the 600 amp panel is located just inside...

My question is about grounding the primary disconnect. Do I run my grounds from the water line, footer and ground rod into this disconnect, or do they get connected inside the panel.

Seems like the grounds would go to the disconnect, but any advice would help...


http://imgur.com/a/xGQRG
 
Either way is fine (not both though) but, I would do it at the disconnect since it's outside the building.

Roger
 
Since that's the service disconnect I agree, the grounding needs to be done inside this disconnect. Don't forget, you will have to have separate grounds and neutrals going to isolated bars in the panels. Looks like you need to add a ground bar in the disconnect.
 
If the disconnect is fused then the grounding electrode conductor must be installed at that disconnect. If it is not fused then either panel is okay.

Also you do not need a ground rod if you have a concrete encased electrode (ufer) -the one connected to the rebar in the footer.

In the future a cheaper way to do this is to install 3- 200 amp disconnects rather than a 600 amp disconnect. My bet is it is a lot cheaper...
 
Dennis Alwon said:
If the disconnect is fused then the grounding electrode conductor must be installed at that disconnect. If it is not fused then either panel is okay.

Also you do not need a ground rod if you have a concrete encased electrode (ufer) -the one connected to the rebar in the footer.

In the future a cheaper way to do this is to install 3- 200 amp disconnects rather than a 600 amp disconnect. My bet is it is a lot cheaper...
Click to expand...

I'm not arguing with you, just asking for the code references (so I can read them) about the fused/non-fused service disconnect comment you made. Thanks.
 
This tells me that the grounding electrode conductor must be connected to the feeder. If there is overcurrent protective device in the first panel then the feeder stops there. If there isn't overcurrent protective device then the feeder also goes to the inside panel.


250.32 Buildings or Structures Supplied by a Feeder(s)
or Branch Circuit(s).
(A) Grounding Electrode. Building(s) or structure(s) supplied
by feeder(s) or branch circuit(s) shall have a grounding
electrode or grounding electrode system installed in
accordance with Part III of Article 250. The grounding
electrode conductor(s) shall be connected in accordance
with 250.32(B) or (C). Where there is no existing grounding
electrode, the grounding electrode(s) required in 250.50
shall be installed.
Click to expand...

250.64(D)(2) Individual Grounding Electrode Conductors. A
grounding electrode conductor shall be connected between
the grounding electrode system and one or more of the
following, as applicable:
(1) Grounded conductor in each service equipment disconnecting
means enclosure
(2) Equipment grounding conductor installed with the
feeder
(3) Supply-side bonding jumper
Click to expand...
 
So, all grounds will terminate in the disconnect? And a jumper installed between the disconnect, new 600 amp panel and existing 200 amp panel?

It just feels awkward running a water line ground to the disconnect...

Also, I actually tried to install a 400 amp service and a 200 amp service, but the inspector said he will only allow 1 meter per structure, unless there are separate units or likely to be in the future. He specified a 600 amp panel.
 
You can have a 600 amp service and still have 3- 200 amp disconnects. You would put the wire coming from the meter into a trough and have 3 - 200 amp panels out of the trough.

The grounding electrode conductors should be connected at the point of the first overcurrent protective device or before it.
 
Dennis Alwon said:
You can have a 600 amp service and still have 3- 200 amp disconnects. You would put the wire coming from the meter into a trough and have 3 - 200 amp panels out of the trough.

The grounding electrode conductors should be connected at the point of the first overcurrent protective device or before it.
Click to expand...

Shouldn't that be " first service disconnecting means"? The disco could also be the service OCPD, but could be separate.
 
jumper said:
Shouldn't that be " first service disconnecting means"? The disco could also be the service OCPD, but could be separate.
Click to expand...

Yeah, I was thinking there was a panel at the meter. Service conductors are still service conductors if the disconnect is not fused. Once you get to the first overcurrent protective device then the grounding electrode conductor can not go any further. Agreed?
 
Dennis Alwon said:
This tells me that the grounding electrode conductor must be connected to the feeder. If there is overcurrent protective device in the first panel then the feeder stops there. If there isn't overcurrent protective device then the feeder also goes to the inside panel.
Click to expand...

Dennis, i dont see 250.32 applying here. I see it as a building supplied by a service. Just because the service disconnect is located on the exterior of the structure doesn't make the building supplied by a feeder.

I also think having a non fused disconnect on the exterior and the ocpd inside is a little sticky code wise. Im sure some AHJ's allow it.
 
New question

New question

The inspector came by and laid out the grounding system, however, I have no idea how to bond the box. It did not come with a bond screw and doesn't have any instructions on how to do so. Any advice would help. Thanks!


http://imgur.com/a/xGQRG
 
oldsparky52 said:
Since that's the service disconnect I agree, the grounding needs to be done inside this disconnect. Don't forget, you will have to have separate grounds and neutrals going to isolated bars in the panels. Looks like you need to add a ground bar in the disconnect.
Click to expand...
That depends, as is there is enough terminals for a paralleled load side neutral conductor, an equipment grounding conductor and a single grounding electrode conductor. Should there be a need to terminate more then that - then a ground bar may be useful.

electrofelon said:
Dennis, i dont see 250.32 applying here. I see it as a building supplied by a service. Just because the service disconnect is located on the exterior of the structure doesn't make the building supplied by a feeder.

I also think having a non fused disconnect on the exterior and the ocpd inside is a little sticky code wise. Im sure some AHJ's allow it.
Click to expand...
I agree on both topics.

Hawkins said:
The inspector came by and laid out the grounding system, however, I have no idea how to bond the box. It did not come with a bond screw and doesn't have any instructions on how to do so. Any advice would help. Thanks!


http://imgur.com/a/xGQRG
Click to expand...
Is it marked "Suitable for use as service equipment"? If so it should have had a bonding method included but typically not pre-installed - make sure it didn't get tossed with other items inside that you likely tossed. If not marked "Suitable for use as service equipment" you have more code problems.

As far as other comments on multiple services, general rules - One service can be up to six disconnecting means all supplied by the same source. Six sets of underground service conductors that all originate at same source and land in six separate service disconnecting means (grouped at one location) is one service.

Six sets of conductors connected at each end (parallel conductors) is only one conductor for determining how many service conductors you have. This would be more typical to use more then two parallel conductors when over 1000 amps but at same time there is no minimum or maximum number of parallel sets per one parallel conductor.

You start reading in 230.2 and follow references to other sections (in particular 230.40) it may give you to decipher all this.
 
kwired said:
That depends, as is there is enough terminals for a paralleled load side neutral conductor, an equipment grounding conductor and a single grounding electrode conductor. Should there be a need to terminate more then that - then a ground bar may be useful.
Click to expand...
If the neutral is grounded in this disconnect, then you will need (2) spaces for the neutral load conductors, (1) for the GEC, (2) for the EGC to the (2) panels, (1) for the supplemental ground rod if you need it. So a minimum of 5, maybe 6 spaces needed. I only see 4 slots available. I guess you could add a lug?
 
oldsparky52 said:
If the neutral is grounded in this disconnect, then you will need (2) spaces for the neutral load conductors, (1) for the GEC, (2) for the EGC to the (2) panels, (1) for the supplemental ground rod if you need it. So a minimum of 5, maybe 6 spaces needed. I only see 4 slots available. I guess you could add a lug?
Click to expand...
What 2 panels? OP said there is a 600 amp panel inside, should only need one equipment grounding conductor. You only need one grounding electrode conductor. You can run bonding jumpers to additional electrodes, and when doing so you can either go from electrode to electrode, or make taps from the GEC.
 
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