Meter Center Configuration - Is this available?

D

designer82

Senior Member
Location
Boston
I need the configuration shown below, where one side is rated 800A (w/ ct & meter) for commercial side of mixed-use building, other side residential.
From experience, do you know if they have something like this available?

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Found out the main needs to be 1,600A and commercial side 1,000A.

I am thinking to just do it like this below and not worry about the meter stack configuration.

What do you guys think?

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electrofelon said:
Are you sure you can do a 1000A Ct cabinet? I know they exist but are rather rare as most utilities (in my experience, YMMV) require a switchboard or switchgear metering section above 800A.
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I haven't been around much for multi tenant situations with that sort of need.

Most larger capacity services I get involved with is usually one transformer for a dedicated customer and they put CT's right on the output spades of the transformer. They may mount the meter on the transformer or seems to be even more common to place the meter on a separate post next to the transformer - seen a little of both, not sure what the reasoning is for one way vs the other. That is mostly the rural POCO's that will do that. There is another POCO that wants a CT cabinet regardless in almost all cases. I suppose it does simplify things some in the case of needing to change out the transformer and can see that being a reason they want the CT cabinet nearly all the time.
 
kwired said:
I haven't been around much for multi tenant situations with that sort of need.

Most larger capacity services I get involved with is usually one transformer for a dedicated customer and they put CT's right on the output spades of the transformer. They may mount the meter on the transformer or seems to be even more common to place the meter on a separate post next to the transformer - seen a little of both, not sure what the reasoning is for one way vs the other. That is mostly the rural POCO's that will do that. There is another POCO that wants a CT cabinet regardless in almost all cases. I suppose it does simplify things some in the case of needing to change out the transformer and can see that being a reason they want the CT cabinet nearly all the time.
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Yeah kind of an interesting situation for the op, if the utility usually just meters at the spades, because he would want the thousand amp set metered at the transformer but then an unmetered set to feed the meter Bank. I would think the Poco could just put the CTS around the desired conductors and skip the others?
 
electrofelon said:
I would think the Poco could just put the CTS around the desired conductors and skip the others?
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They could but most won't. They have design standards that they seldom will vary from no matter the situation.

Some of it is based on keep it simple and consistent so no matter what technician shows up when something needs done, it is generally the same basic configuration at every location.

I remember upgrading service to a school building one time, they went from single phase pad mount to a bigger three phase pad mount so a lot was changed though the underground into the building was still sufficient for my service conductors so we didn't touch most the underground portion of those. After the first energy billing came out, was in the summer school was out of course and we were still working in there, I noticed a POCO guy out working in the transformer even though that portion of the project was done. I talked to him, turns out they had a negative consumption that first month, someone wired the metering wrong and he was there to straighten it out.
 
I appreciate all the valuable feedback!
I was reading the National Grid Standards and they do in fact seem to have some wording on "transformer rated CT Cabinets 400-800 Amp".
So it may be that they cap at 800 Amp.
I reached out to them but they'll take a long time to answer and prob. won't even understand what's going on.

To simplify things, I'm thinking I'll just change it to 2 (600A each) CT Cabinets/meters for the one commercial tenant. Let them have 2 meters, so what.

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designer82 said:
I appreciate all the valuable feedback!
I was reading the National Grid Standards and they do in fact seem to have some wording on "transformer rated CT Cabinets 400-800 Amp".
So it may be that they cap at 800 Amp.
I reached out to them but they'll take a long time to answer and prob. won't even understand what's going on.

To simplify things, I'm thinking I'll just change it to 2 (600A each) CT Cabinets/meters for the one commercial tenant. Let them have 2 meters, so what.

View attachment 2576288
Click to expand...
They make CT cabinets from 400 - 4000.
You need a better group of product reps to educate on what your material options are.

If I were a customer and ever heard my EE or EC use the term “so what”, we would be done. If you cannot defend your design choice…let someone else do it.
 
MyCleveland said:
They make CT cabinets from 400 - 4000.
You need a better group of product reps to educate on what your material options are.
Click to expand...

Yes but the issue is some utilities will require a switchboard with a metering section. I admit I am not really clear if there is a distinction, or why there should be a distinction, between a standalone CT cabinet and a "CT cabinet" incorporated into a switchboard. I am just saying that the op should check metering requirements with the power company before designing.
 
electrofelon said:
Yeah kind of an interesting situation for the op, if the utility usually just meters at the spades, because he would want the thousand amp set metered at the transformer but then an unmetered set to feed the meter Bank. I would think the Poco could just put the CTS around the desired conductors and skip the others?
Click to expand...
Most of the time when this happens on a service of this size, we are required to use a bused CT cabinet. I think you can get up to a 4000 amp rated bused CT cabinet.
 
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