This article was posted 08/19/2013 and is most likely outdated.

Mike Holt - Smart Meter Disconnect
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Smart Meter Disconnect

Smart Meter Disconnect

Can anyone help out with a question from Bruce?

smart meter“I have a concern about the safe operation of the disconnecting means within the new Smart Meters.  I wonder about the interrupt current rating and the short circuit fault current rating of the internal remotely controlled disconnecting means within the GE I-210+ meter. 

Do you have any experience with or information on these devices?

I am unable to obtain answers from either the local utility installing these meters or from the manufacturer.  UL responds that the GE Smart Meters are not listed.  The manufacturer (GE) relates that the information is proprietary and said I need to talk with the utility.  I have had a face to face meeting with utility representatives and Email correspondence.  Utility representatives decline "to share", to quote their response, the information requested.  I have been told that the switch is about the size of a deck of cards and is located in the back of the meter. 

I have asked the following questions that the utility company representatives declined to answer.

  1. What is the interrupt current rating of the remote disconnect means within the meter?
  2. How was this interrupt current rating established?
  3. If this rating is based on an ANSI or other Standard, what is that Standard?  If not based on a Standard, what is the foundation for this rating?
  4. Has the internal remote disconnect means been tested at the interrupt or short circuit current rating to insure safe operation?
  5. If this has been tested, what lab or facility conducted the test?  What current rating was used in the test?  Is a test report available for review?
  6. What type of overload protection is offered for the internal electronic circuits (e.g. the power supply) should there be a failure within these circuits?

Technical specifications of the I-210+ meter may be found in the GE Digital Energy document "Residential Electrical Metering" that is available at this URL: http://www.gedigitalenergy.com/products/brochures/i210_family.pdf.  A number of Standards that the meter is designed to be compliant with are listed in this publication however none of these seem to address the ratings of the disconnecting means. 

Another manual, GEH-7287 is available at:
http://www.gedigitalenergy.com/products/brochures/i210_Installation.pdf . This manual does not seem to address testing of the disconnecting means.

I realize that the meter may not be considered service equipment and the utility is not required to be NEC® compliant however, I cannot help but consider the comments in the NFPA 70 Handbook following Article 110.24 that relate the following: "Equipment must have an interrupting rating or short-circuit current rating equal to or greater than the available fault current if it is to be used safely.  Any equipment operating with ratings less than the available fault current is potentially unsafe." 

Without the ability to determine the ratings of this, and maybe other Smart Meters, how does one determine that the meter is a safe product and does not constitute a safety hazard where installed?  Or, am I being overly concerned about the safe operation of the disconnecting means within this device. 

Any information you may have would be greatly appreciated as I desire to offer safe and reasonable guidance to my client.”

Mike’s Comment: If you have an answer, or any information or resources that will be helpful, please help Bruce out by posting your comment below.

 

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Comments
  • Bruce has a legitimate concern. If this were covered by the NEC, 110.10 and 230.82(3) would apply. In no case, whether covered by the NEC or the NESC, should equipment ever be applied beyond its short-circuit current rating. Unfortunately, even when covered by the NEC, equipment, such as a meter stack, has a short-circuit current rating that normally covers only the meter socket. It does not normally cover the meter. It seems as if the listing agencies close their eyes when it comes to what happens when a meter is installed in the equipment.

    Ugottaluvit  August 20 2013, 10:08 am EDT

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