# Understanding NEC 2020 and disconnects required



## magicone2571 (Apr 29, 2021)

I've been out of the game for a little bit (hence all my recent questions). I'm installing a new 400 amp service for a client. It will have two 200 amp panels feed off the meter, one is in the house, other in the attached new garage. NEC 2020 now requires disconnects to be outside and grouped. My initial thought was to use a meter main combo with two 200 amp breakers. But after speaking with the poco today, they said I can't use that. I have to use two separate 200 amp disconnects.

My questions is how to I wire it correctly? I have to bond the neutral/ground in each disconnect but since they are going to the same building, do I then bond the disconnects together? Would I need to do 4 ground rods vs 2? Not sure what the best option is. I doubt there is a 400amp panel with 2x 200amp breakers that would be anywhere near cheap. I can find a 200amp disconnect but I can't find one with 250kcmil neutral and 3/0 ground lug. 



Any advice? Thanks


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## Wardenclyffe (Jan 11, 2019)

I










I have this at my house, two breakers inside the right side,...


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## magicone2571 (Apr 29, 2021)

Wardenclyffe said:


> I have this at my house, two breakers inside the right side,...


Poco said no. They won't allow a meter main combo. Has to be two seperate disconnects. Like the photo below. I guess I just install 4 ground bars, 2 for each disconnect.


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## Forge Boyz (Nov 7, 2014)

2 ground rods will be fine.1 #6 to the rods will be fine, as long as it is one piece or crimped together. What you could do is drive the rods centered on the meter base and run the GEC from 1 disconnect, down to the rods and back up to the other disconnect.

Sent from my SM-G970U using Tapatalk


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## Dennis Alwon (May 9, 2009)

Why do you need 250 kcm for the neutral?

Will power company allow you to install the grounding electrode conductor in the meter?

If not then run a #6 from the first disco to the first rod and loop it thru to the second and up to the second disconnect. Basically a long loop.

Now the problem.... you cannot run 2 feeders to one building.



> 225.30 Number of Supplies. A building or other structure
> that is served by a branch circuit or feeder on the load side of a
> service disconnecting means shall be supplied by only one
> feeder or branch circuit unless permitted in 225.30(A)
> ...


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## magicone2571 (Apr 29, 2021)

Dennis Alwon said:


> Why do you need 250 kcm for the neutral?
> 
> Will power company allow you to install the grounding electrode conductor in the meter?
> 
> ...


I've gone back and forth with the poco on this for the last week. This is how they do a 400 amp service. The disconnect has to be grouped and at the meter. Not sure how else we would do it without going to a 400 amp panel and disconnect. But that would be $$$$$. 

As for the 250 neutral, it's like 250ft from disconnect to panel. And only would save like $20 to derate it so I just ordered 250/250/250/(3/0) for the feeders.


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## Dennis Alwon (May 9, 2009)

The NEC doesn't care about cost. The way you are doing it will not be compliant so it is up to the authority having jurisdiction to deal with it.


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## magicone2571 (Apr 29, 2021)

Dennis Alwon said:


> The NEC doesn't care about cost. The way you are doing it will not be compliant so it is up to the authority having jurisdiction to deal with it.


I left a message with the local inspector, I'll get his input. Though I think the client could get an exception under number 2. The place where the 2nd panel is going is a huge 6000sqft workshop. It's only connection to the primary structure is a 10ft wall.


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## Dennis Alwon (May 9, 2009)

magicone2571 said:


> I left a message with the local inspector, I'll get his input. Though I think the client could get an exception under number 2. The place where the 2nd panel is going is a huge 6000sqft workshop. It's only connection to the primary structure is a 10ft wall.



Well that changes things... Run one run to the first structure and the other run to the shop


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## magicone2571 (Apr 29, 2021)

Dennis Alwon said:


> Well that changes things... Run one run to the first structure and the other run to the shop


That's the current plan unless it changes again. Every time I speak to the poco they say something different. Only thing left I can't find is a 6x6x36 n1 gutter box. All the suppliers are out. Been a nightmare sourcing supplies.


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