Aftermarket usage metering???

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laramie

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All,

Thanks again for any help. We are currently working on a 15K sq.ft office space, (building is shaped like a giant letter "T") serviced by a 800A 120/208 service. There is only one meter for the building, with a 400A disconnect in each major wing, with 200A distribution panels set for lighting & power. However, the tenant would like to separately monitor usage on each wing, common area in the middle, future tenant space in the basement, etc. That way, they can divvy up the electric bill every month, rather than just "assume" space A used 20%, space B 20%, etc.

Is there any aftermarket device that can be installed to separately monitor each distribution panel? It also seems to me that instead of our two major distribution panels, in order to make this work i'd need to have more panels installed that service these particular areas only, in order to be accurate.

Any help would be appreciated!

Thanks
 
Sub-metering is done all of the time, especially at marinas and campgrounds. Here is one source for the meters, I am sure there are many others - http://www.texasmeter.com/english/newmeters.html.
You are correct that the loads will need to be subdivided in order to accurately measure the usage in different areas. When the owner finds out what that will cost, they may decide that the electric bill is not a big deal.
 
Consider looking for a solution that does not require the installation of a meter socket; one that simply uses CTs and voltage leads. If you do install a meter socket, the neutral will have to go through the socket enclosure without connecting to the bonding strip.
 
Both Square D and EMON-DMON offer submetering without meter bases.
And, I know there are others.
 
Caution your client to check with the utility commision governing the area. In New Mexico, the submetered bill must be calculated exactly the same way the overall bill is calculated.

If the overall bill has demand and energy charges separately, the sub bills must also. The sub bills mut determine the demand value at the time the overall service demand was set, you can't use the individual demand readings, as the sum of them would exceed the overall demand reading.

In essence, it is very difficult to submeter and bill legally in this jurisdiction. The saving grace is that someone has to complain before the PUC gets invloved, and not many people know to complain.

Jim T
 
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