Help me understand vertically bussed meter stacks

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Tainted

Tainted

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Location
New York
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Engineer (PE)
I am specifying meter stacks and the stack I will be using is rated 160 amp continuous model VMB-4. See this table:

a.jpg

The meter stacks with vertical bus's look like this, see page 27:
https://s3.amazonaws.com/dcc-data-extract/new-delta/asset/Compas/daily/Compas/Selection Application Guide/SIE_SA_POWERMOD_NYC_Metering_SelectionandApplicationGuide.pdf?10102022

There will be a 600A feeder under these stacks which feed the meter banks like this:


unnamed.jpg


are we allowed to stack (4) 200 amp apartments in a single 160A continuous rated vertical bus? Is it dependent on NEC 220.84? How will we know if there will ever be continuous load of more than 160A if we don't know how long and how much each tenant will be running their equipment? Why is it rated at 160A continuous if we can put up to (4) 200A apartments in a single vertical bus? I would also like to mention that it is extremely difficult to find a continuous bus rating of more than 200A
 
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electrofelon said:
I think the line bus is rated higher. The 160A is per position, or for an individual socket
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hmmm, I was under the impression each vertical line bus is rated 160A. I never really understood what was meant by "position" I thought "position" meant rows of meters.

What should the wire size be between take off lugs and the vertical buss? Should it be dependent on 220.84? There's really no guidance on this anywhere... or maybe I am just too dumb to figure it out.

pb.jpg

I think each take off lug can only handle 4/0 wire which is like 230A..

tol.jpg
 
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Tainted said:
hmmm, I was under the impression each vertical line bus is rated 160A. I never really understood what was meant by "position" I thought "position" meant rows of meters.

What should the wire size be between take off lugs and the vertical buss? Should it be dependent on 220.84? There's really no guidance on this anywhere... or maybe I am just too dumb to figure it out.

View attachment 2563294

I think each take off lug can only handle 4/0 wire which is like 230A..

View attachment 2563295
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Actually I think these lugs are for the 100A continuous stacks, not 200A continuous stacks
 
electrofelon said:
Yeah I would say you would size the feeder supplying the meter stacks to the load calculation.

The takeoff lugs have multiple ports not just for a single conductor.
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can you put 2 sets of 2 conductor cables between the take off lugs and a single vertical meter bus? I did worste case scenerio calculation for (4) 200A apartments on a single vertical bus and the total amps came out to be 360A. That would mean I would need 2 sets of 3/0 between the take off lugs and the vertical bus
 
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My take on it, without doing a bunch of digging, is that those take off lugs bolt to the stack bus and are available with 3,6,or 12 lugs per phase.
Tainted said:
can you put 2 sets of 2 conductor cables between the take off lugs and a single vertical meter bus? I did worste case scenerio calculation for (4) 200A apartments on a single vertical bus and the total amps came out to be 360A. That would mean I would need 2 sets of 3/0 between the take off lugs and the vertical bus
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I am a little confused and dont quite understand how this goes together, and where the take off lugs mount.
 
electrofelon said:
My take on it, without doing a bunch of digging, is that those take off lugs bolt to the stack bus and are available with 3,6,or 12 lugs per phase.

I am a little confused and dont quite understand how this goes together, and where the take off lugs mount.
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Yes, if you look at the meter bank picture in my first post, you will see the take off lugs on top of the lugs where the 2 sets of wires terminate to
 
electrofelon said:
So you have to field wire between those lugs and each meter stack? Weird set up.
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Yup, looks way too homebrew but it's apparently legal and approved by Con-Edison. Eaton and siemens makes these differently without the take off lugs, only buses
 
electrofelon said:
And those are pull out fuses above??? Seems like the most convoluted way to do it!
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Yes those are pull out fuses by bolt switch lol. Apparently these pullout fuses only take class T type fuses. I just don't understand why we can't just use any other fuse? manufacturers are weird.
 
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