400amp 3 Phase Service split into two 200 Amp

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SJElectrician

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I will be installing a 3 phase 208/120 400 amp service. I will be installing down the pole a set of parallel Alum 250mcms up into a CT Cabinet. I will just pass trough the CT'S themselves, no splices allowed per Utility Co. So I want to leave CT cabinet, still parallel, each set into its own 2-1/2 pvc up into a 200amp fused disconnect. Is this allowed? I don't see a reason to enter into an auxiliary gutter after the cabinet, bug together (they are bugged at XFER on pole), and add new wire to go up into the disconnects. This is for a detached garage also. Thanks in advance for any advice.
 
Welcome !
Interesting question.
I know of no NEC violation but I can't speak for the CT situation.
There are guys here who are familiar with POCO CT requirements. Hopefully they will advise further.
 
I agree with Augie. Your POCO would be the only one who would have a say in this. I can't imagine any reason they would say no.
 
SJElectrician said:
I will be installing a 3 phase 208/120 400 amp service. I will be installing down the pole a set of parallel Alum 250mcms up into a CT Cabinet. I will just pass trough the CT'S themselves, no splices allowed per Utility Co. So I want to leave CT cabinet, still parallel, each set into its own 2-1/2 pvc up into a 200amp fused disconnect. Is this allowed? I don't see a reason to enter into an auxiliary gutter after the cabinet, bug together (they are bugged at XFER on pole), and add new wire to go up into the disconnects. This is for a detached garage also. Thanks in advance for any advice.
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Sounds to me like allowed by 230.40 exception #2. I assume the conductors on the line side of the CT will be in parallel as there will be a mounting base with lugs in the cabinet. Either way is fine.
 
It does not sound like parallel conductors. If the conductors are connected at one end and then go to 2 separate panels you will have a violation. You will have to bug them together and come up individually into the disconnects. IMO
 
Dennis Alwon said:
It does not sound like parallel conductors. If the conductors are connected at one end and then go to 2 separate panels you will have a violation. You will have to bug them together and come up individually into the disconnects. IMO
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what is the violation ?
Sounds like two services tapped off one transformer.
(ignoring metering all together)
 
I re-read the OP. First go around I assumed the disconnects were grouped, but it is not clear if that is the case. If they are grouped, 230.40 ex#2 applies. If not, and assuming 230.40 exception #3 doesn't apply, then depending on where the service point is, we are in that philisophical gray area of whether the NEC has any business or authority on how the utility supplies services.
 
Since he mentioned a gutter I also assumed "grouped" and was relying on Exception #2 to 230.40 also.

He also mentioned a detached garage...If one of the services is for that garage it seems he could run from the CT cabinet to the garage and eliminate the 2nd disconnect on the building.

We need a bit more detail.
 
It's a 400 amp 3 phase service for a machine shop of mine. Its all mounted on the outside wall of garage. I want to split it into 2 200 amp panels inside the building. I don't want the expense of a 400 amp disconnect outside so I want to use 2 200 amp grouped disconnects outside. The CTs will be monitoring the entire 400 amp service so it's only one service in my mind. So...I originally thought the CT cabinet would have lugs inside to land on but that isn't the case in South Jersey. I can only mount the CTs in cabinet and have the wires pass through them and then out of cabinet. Then I could go into a gutter under both disconnects and bug phases back together with Polaris Electrical Connectors and feed each disconnect. Basically I don't want to bug back together just to seperate them again to go to the two 200 amp disconnects. Seems of extra money and work when I can just exit out of the CT Cabinet to each disconnect in it's own pipe. Most people would pull a single set of wires and split off in the gutter or CT Cabinet on lugs if allowed. I am pulling parellel feeds so I'm already split. In the pic below I would have two pipes coming up in CT Cabinet. And I would ditch the gutter.


Underground CT Metering Service.jpg
 
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230.40 Exception 2, get's you there as far as the NEC is concerned. But I would run it by your service planner to ensure that he doesn't have a problem with it.

As a machine shop, with 200A panels, you will be likely limited to 100A branch breakers with most plug on units. Are you sure that this is adequate for your largest machine loads? Or do you need to consider a bolt on panel that accepts larger breakers?
 
SJElectrician said:
It's a 400 amp 3 phase service for a machine shop of mine. Its all mounted on the outside wall of garage. I want to split it into 2 200 amp panels inside the building. I don't want the expense of a 400 amp disconnect outside so I want to use 2 200 amp grouped disconnects outside. The CTs will be monitoring the entire 400 amp service so it's only one service in my mind. So...I originally thought the CT cabinet would have lugs inside to land on but that isn't the case in South Jersey. I can only mount the CTs in cabinet and have the wires pass through them and then out of cabinet. Then I could go into a gutter under both disconnects and bug phases back together with Polaris Electrical Connectors and feed each disconnect. Basically I don't want to bug back together just to seperate them again to go to the two 200 amp disconnects. Seems of extra money and work when I can just exit out of the CT Cabinet to each disconnect in it's own pipe. Most people would pull a single set of wires and split off in the gutter or CT Cabinet on lugs if allowed. I am pulling parellel feeds so I'm already split. In the pic below I would have two pipes coming up in CT Cabinet. And I would ditch the gutter.


View attachment 20254
Click to expand...

That is odd they dont use mounting bases and bolt on CT's there. I have never known a utility to do it that way. Have done it that way for customer metering of PV plants though. Anyway I see no issue. It falls under 230.40 Exception #2, as has been mentioned.

Just to be clear, you are not using the correct terminology. Parallel conductors would be tied together at both ends. What you have is two sets of service conductors. In your case there are two sets all the way from the service point to the disconnects. What I usually would see for this setup is parallel conductors from the service point to the line side CT lugs, then on the load CT lugs, changing to two sets, each to separate disconnects. Either one is compliant as long as the utility doesnt have some specific requirement.
 
I was anticipating seeing lugs in the CT Cabinet also. It was just a wood backboard and three loose CTs for me to mount. The Atlantic City Electric Engineer said he doesn't have an issue with it. I was more concerned about the AHJ. I haven't been able to reach him yet and just wanted to make sure I wasn't seeing something that I should be. The shop the equipment is in currently has a similar amp service. It will now be on my property instead of renting.:D
 
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