Power Meters

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jbwhite

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The facility that I work in wants us to provide suplemental power meters and tie them into the Building Automation System via the Base Wide Network.

We will be installing these meters in several buildings.

The physical size of the meters prohibits us from installing them in the main panel in some buildings.

We are proposing installing a J box and running the service cables through the meters in the manner shown on the drawing linked here.

http://members.cox.net/jwhite480/Drawing3916meters.jpg

What possible code issues will we run into?
 
What type of values are you looking for:kW & KWh only or V,A, PF, Freq, etc.....

Appx. how many points are you plannig to monitor.

Also you mention tying these to your facilities existing network, what protocol's are supported on your network?

There are any number of options depending how extensive you plan to go within your distribution system.

The following links are to Square D's PowerLogic and Schndier's PML Metering sites, both are represented through the Square D local office.

http://www.powerlogic.com/products.cfm
http://www.pml.com/home/
 
For some reason I couldn't see your jpeg. Must be that that site requires cookies. Anyway,

The 2002 & up NEC is much more liberal than previous versions, as far as permitting different voltages to ground in the same raceway. Basically, 300.3.C.1 allows mixtures of wiring in raceways under 600 volts. The handbook has many references indexed under 'different systems, conductors in same enclosure' but the units you'll be working with will be listed and made to work as you've described.

As long as there is adequate space available, the NEC permits using panels for CTs, as junction boxes, etc. Section 314.16 covers fill issues here. Please note that some energy management equipment is listed for use in panels, which helps avoid arguments.

It will be necessary to take power from the circuits you are monitoring, using inline fuses to protect the metering unit. The way to provide this power is the only gray area, in fact. Since it is a negligible power drain, there's no reason to provide for loads or install extra breakers just for this. You can either double lug on an existing circuit breaker's terminals or remove wires and use a wire nut and jumper. The second method does not require breaker lugs approved for two wires, avoids possibly placing two different sized wires in the lug, and is less 'contentious' than the first.

Gedwards, did you know that that fantastic looking enercept meter is also available from a square d spinoff company here. It looks wonderful, but I haven't had the chance to install one (yet.) Wish I could find customers besides strip malls who see the value in accounting for energy use...


edit: I'm wrong wrong wrong. Acquisuite is ex-square d, not veris.
 
some years ago we were contacted by an office building owner concerning installing a power metering system because one of their tenants had changed their operations to work around the clock on a product they figured was very important to the cell phone market. actually it was the development of the nextel telephone system. their lease agreement allowed them a standard amount of wattage per square foot per day. the building owner and the tenant(motorola) realized they were exceeding it, and motorola had agreed to pay to install some type of metering system to determine what their far share was above their lease agreement. we suggested and installed the e-mon computerized metering system.

years later, motorola moved out, but the building owner continued to monitor new tenant power comsumption and held them to the standard usage as specified in their lease ageement --like 5 watts per square foot. they found out that the money saved payed the chief engineer's salary and the building wasn't that large. they require a new tenant to pay for the installation of the meter to their system, which prints out a legal bill monthly. many building owners are operating on power consumtion standards from tenant operations twenty or thirty years old....... this metering system doesn't cost------------it pays!!
 
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