High leg delta service.

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georgefit
Posts: 2
Joined: Mon Aug 03, 2015 8:50 am

High leg delta service.

Post by georgefit »

Will a EKM meter accurately measure kwh of a 200 amp 3 phase high leg delta,120/240 volt, 4 wire sub service when over 90 % of the load is single phase connected to the centered taped transformer? The only three phase loads are several overhead cranes.
The service is typical of old industrial services. Three 1 phase transformers wired in delta with one transformers center tap grounded as the neutral. If the neutral is connected to the meter the potential would be over 200 volts on the high leg, is this acceptable?
Regards,
Nevland
Posts: 65
Joined: Tue Jul 31, 2012 2:56 pm
Location: Nevada City CA

Re: High leg delta service.

Post by Nevland »

My generator seems to wired the same way. Not using the high leg at this time, but would be nice to know about it in case I wanted to use a piece of 3 ph equipment.

Bill
Jameson
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Joined: Fri Nov 04, 2011 7:42 pm
Location: Santa Cruz, CA
Contact:

Re: High leg delta service.

Post by Jameson »

Yes, any of our Omnimeters will work with this. We call this a 3-phase 4-wire system. It does not matter if the load is unbalanced, the meter will work well with this (it measures voltage and current simultaneously on each line and combines them). You will need 1 Omnimeter and 3 CTs for this kind of a system. All of our Omnimeters will be able to work with over 200 volts hot to hot.

You will wire it just like this: http://www.ekmmetering.com/information/ ... ml#answer8

You may find our 3-phase 4-wire metering package useful for placing your order: http://www.ekmmetering.com/3-phase-4-wi ... ckage.html

Please let us know if you have any questions.
Jameson
EKM METERING
http://www.ekmmetering.com
831.425.7371
georgefit
Posts: 2
Joined: Mon Aug 03, 2015 8:50 am

Re: High leg delta service.

Post by georgefit »

jameson,
"All of our Omnimeters will be able to work with over 200 volts hot to hot."

It’s the hot to neutral voltage I am concerned about. In a high leg delta application, connecting the neutral to the meter will destroy at least one of your competitor’s meters. I have not been able to achieve desired accuracy without a connected neutral. I attribute this to the imbalance of the loads. My plan is to replace these meters with Omnimeters if revenue accuracy can be achieved metering 120/240 three phase high leg delta.
Regards,
georgefit
Jameson
Posts: 860
Joined: Fri Nov 04, 2011 7:42 pm
Location: Santa Cruz, CA
Contact:

Re: High leg delta service.

Post by Jameson »

Hi georgefit,

Thanks for clarifying. Yes, you will be easily within spec for our Omnimeters when used to meter a 120/240 volt three phase High Leg Delta system.

The Omnimeter Pulse v.4 and Omnimeter Pulse v.4 UL are both ANSI C12.1 and ANSI C12.20 tested and certified. This is a Revenue Grade Accuracy certification for your system.
Jameson
EKM METERING
http://www.ekmmetering.com
831.425.7371
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