"Grouping" How would you interpet this 400amp

[sparky1346]

I had built a 400 amp service on a new home, one panel is fed off double lugs directly to the panel, inside the other is fed through a 200 amp main outside to a 200 amp panel inside next to the back to back panel. All panels are within 4 feet of the meter. I do believe this is considered grouped ! Could someone tell me where in the Code Book it says that panels are not grouped if they are on the same wall but not inside of each other. (All three mains can be physically touched at the same time)

 

[benaround]

Re: "Grouping" How would you interpet this 400amp

sparky1346,

230.72 --Grouping of disconnects. I don't fully understand the setup you have.

frank

 

[tom baker]

Re: "Grouping" How would you interpet this 400amp

If I understand your post, the panels are on opposite sides of a wall. To me this is not grouped. Grouped is not defined, but in reading thru the section on service disconnects it referres to 6 disconnects being grouped, IE in the same place.

Perhaps Ive answered your question, but what is the issue?

 

[russ]

Re: "Grouping" How would you interpet this 400amp

230.72 rquires that the disconnects be grouped.

I don't understand how you can have a single two hundered amp main outside, and the other 200amp panel inside and have the mains grouped.

[ May 12, 2005, 10:27 PM: Message edited by: russ ]

 

[john m. caloggero]

Re: "Grouping" How would you interpet this 400amp

Question: i built a 400 amp service on a house, one panel is feed off double lugs direct to panel inside the other is feed through a 200 amp main out side to a 200 amp panel inside next to the back to back panel all panel are within 4 feet of the meter i believe this is grouped ?????????? please


Sparky: Answer: Based on your description (not very clear) as I understand it; you have a panel with a disconnecting means in it. You supply a second panel from the main lugs, therefore, you have one panel outside the building and another panel inside the building. If the panel inside the building is supplied from the main lugs ahead of disconnecting means, the inside panel must have a disconnect and overcurrent protection if it is a lighting and appliance panelboard. So you would have two service disconnect outdoors and one disconnect indoors. In that installation, they are not grouped. If the inside panel is supplied from the load side of the outdoor disconnect, the inside panel is now supplied by a feeder and the neutral must not be grounded in the inside panel and nor used for grounding the panel.

 

[mc5w]

Re: "Grouping" How would you interpet this 400amp

I think that he means that he has 2 service disconnects, 1 inside and 1 outside. The inside disconnect is located in its main breaker panel. The outside disconnect feeds a 2nd interior panel next to the first panel. I think that he is also trying to say that the 2nd panel also has its own main breaker. Makes me wonder why he has the outdoor disconnect since it is redundant and unnecessary.

Common sense says that for the disconnects to be grouped they must be on the side of the wall. National Electrical Code seems to be highly dependent on common sense. The real problem comes when NEC allows you to do services 2, 3, or 4 different ways and the inspector was only trained to do services 1 way.

 

[allenwayne]

Re: "Grouping" How would you interpet this 400amp

I don`t understand why you would back to back 1 200 a mbr panel and mount a disconnect adjscent to the meter and then feed a 200 a mlo when all you had to do was back to back 2 200 mbr panels.Or am I missing something ???
Even those small 320/400 amp meter bases can serve 2 back to back mbr panels,heaven knows I have built enough of those.In your senario they would not be grouped and here it would fail but if you had 2 exterior disc`s feeding interior panels or 2 back to backed mbr panels these would be fine.

 

[james wuebker]

Re: "Grouping" How would you interpet this 400amp

Spary1346
You have a 400 amp meter base. Do you have a 400 main disconnect or do you have from the meter a set of wires to the outside panel and a set to the inside panel?
Jim

 

[suemarkp]

Re: "Grouping" How would you interpet this 400amp

Originally posted by sparky1346:
All three mains can be physically touched at the same time

I think this is the key. If you in fact put disconnects on opposite sides of a wall, how can you touch all of them at the same time? I would say things are grouped if you can stand there facing the disconnects and without moving your feet reach all the disconnects.

 

[allenwayne]

Re: "Grouping" How would you interpet this 400amp

Not sure if the moving of the feet is an NEC issue but I do think opposite sides of a building Inside/outside would be the problem
Still can`t figure why one outside disc and a b/b panel and a b/b mbr panel instead of 2 b/b mbr panels

 

[amptech]

Re: "Grouping" How would you interpet this 400amp

allenwayne,
Guys try to get away with this around here once in a while to save $100.00 on a 200A w/p disconnect. They want a 400/320 service to a new home so they can feed 200A to the house and another 200A to an outbuilding they are going to use for a shop. They mount the house panel, a MB, back to back with the meterbase on the house. Then they come out the side of the meterbase with a nipple and hit a 3R 200A disconnect. Then they come out of the disconnect and go UG to the shop with 4/0 AL URD. In my opinion these disconnects are not "grouped". One disconnect is inside and the other is outside. I either use (2) 200A w/p disconnects or a 320/400 meter main with (2) 200A breakers built in.

 

[luke warmwater]

Re: "Grouping" How would you interpet this 400amp

Sometimes a picture is worth 300 posts.
Could you post a picture of the installation?

 

[allenwayne]

Re: "Grouping" How would you interpet this 400amp

Amptech why not use a 200 amp feed through panel for the outbuilding and a standard 200 mbr panel for the house,that would be cheaper than using a 3 R disc and a MLO panel.Couple of lb`s some pipe that would be there anyway done deal
Getting back to grouping IMO the first senario would not be acceptable,1 inside 1 outside

 

[james wuebker]

Re: "Grouping" How would you interpet this 400amp

Amptech, Just did almost the same as the guys you were talking about. Put a 320/400 meter and ran inside 2 sets of wires in a morton building. A 200 disconnect for the house and next to it I put in a 200 amp Sq. D 40 space panel with a main for the morton building.The panels were side by side on the inside of the buiding. Of course the meter was on the outside.Now I believe these are grouped together.

 

[mc5w]

Re: "Grouping" How would you interpet this 400amp

Some electrical utilities prohibit using the knockouts that are on the backside of a meter socket when the meter socket is mounted on a building. Essentially, this creates too many problems wiht trying to seal against moisture coming in from the outside or moisture coming fromminside the house and freezing inside or outside of the back of the socket.

 

[allenwayne]

Re: "Grouping" How would you interpet this 400amp

Originally posted by mc5w:
Some electrical utilities prohibit using the knockouts that are on the backside of a meter socket when the meter socket is mounted on a building. Essentially, this creates too many problems wiht trying to seal against moisture coming in from the outside or moisture coming fromminside the house and freezing inside or outside of the back of the socket.

I have built literally 100`s of 400 amp back to back services and have never heard of that.the KO`S are ul listed for rear entrance into the meter base.I have encountered areas that want the perimeter of the meter can caulked but have never heard of a poco requiring that the meter not have a rear penetration in it.After all how is it mounted on a surface mount install if not through the rear of the enclosure

 

[hurk27]

Re: "Grouping" How would you interpet this 400amp

I too have used the back KO's to feed the panel out of a meter, but I have to use only the middle KO or teh utility get's alittle upset.

As far as mositure freezing in the nipple. 300.7 will clearly solve that problem if it is followed.

Haveing a service disconnect on the outside of the building and then have a main breaker panel inside would be a violation of grouping.
I would belive the intent is the same as for the six movments of the hand requirment, which would require the disconnects to be close enough to be reached, without much movment of the operator to another location, and should be within sight of each other.

Amptech:
If you supply an outbuilding why would you install a 320/400 meter then install a disconnect to feed the outbuilding?
first if the service conductors do not enter a building they do not need a disconnect, second you will still need a main disconnect that is service rated, at the outbuilding if you have over six circuits! ( which I think you would with a 200 amp panel)

Why not just use the second set of lugs and run to the out building and hit a main breaker panel as we are allowed by the exception #3 in 230.40?

Then this feed is a service conductor feed which only has to meet the requirment's of 230. Which would mean that these conductors are service entrance conductors. Only three wires would be ran and you would bond to the grounded conductor as 250.142 allows. Install a ground rod or two and be done which a ground rod would have to be installed anyway.

 

[amptech]

Re: "Grouping" How would you interpet this 400amp

hurk, The outbuilding will also have phone lines and possibly CATV from the house making a 4 wire service necessary. The 200A disconnect or feed from a 320A meter main would terminate in a 200A MB panel at the outbuilding.

 

[hess]

Re: "Grouping" How would you interpet this 400amp

so what you are telling me amptech, if you feed a different service to a detached building and the power company feeds it from the same transformer that feeds the residence. then you run telephone lines from the residence to the detached building then the power company must run a equipment grounding conductor.
i dont think so.
just remember a meter socket is not service equipment. 230.66

 

[George Stolz]

Re: "Grouping" How would you interpet this 400amp

Originally posted by amptech:
hurk, The outbuilding will also have phone lines and possibly CATV from the house making a 4 wire service necessary. The 200A disconnect or feed from a 320A meter main would terminate in a 200A MB panel at the outbuilding.

As long as no disconnect stands between the transformer and the outbuilding, the conductors between the transformer and the outbuilding are service entrance conductors.

250.32 Buildings or Structures Supplied by Feeders or Branch Circuit(s).

250.32 doesn't apply.