The U.S. National Work Group (USNWG) formed in August 2012, to develop proposed requirements for commercial electricity-measuring devices (including those used in sub-metering electricity at residential and business locations and those used to measure and sell electricity dispensed as a vehicle fuel) and to ensure that the prescribed methodologies and standards facilitate measurements that are traceable to the International System of Units (SI). This work is not intended to address utility metering in the home or business where the electricity metered is consumed by the end purchaser and that falls under the authority of entities such as the local utility commission.
The USNWG will review and propose changes as needed to:
- Draft requirements for equipment used to measure and sell electricity in commercial applications for possible inclusion in NIST Handbook 44 (HB 44), ''Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices''; and
- Draft procedures for type evaluation, laboratory, and field testing of equipment for possible inclusion in NIST Examination Procedure Outlines and other procedure documents.
Included among the topics to be discussed by the USNWG for current and emerging device technologies used in commercial electric measuring systems are: (1) Method-of-sale requirements; (2) metrology laboratory standards and test procedures; (3) uncertainties; (4) measurement traceability; (5) tolerances and other technical requirements for commercial measuring systems; (6) existing standards for testing equipment; (7) field implementation; (8) data analysis; (9) field test and type evaluation procedures; (10) field enforcement issues; (11) training at all levels; and (12) other relevant issues identified by the USNWG.
The USNWG's technical output may result in the revision of current standards or the development of new standards for testing equipment, including documents such as the NIST Handbook 105 Series: Specifications and Tolerances for Reference Standards and Field Standard Weights and Measures available on the NIST OWM/Publication website; NIST HB 44: Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices, and NIST Examination Procedure Outlines (EPO), as well as proposed changes to requirements and testing procedures for commercial devices and systems used to assess charges to consumers for electric vehicle fuel.
On August 26, 2016, the USNWG agreed to modify its June 2013 version of Operational Guidelines to restructure into two subgroups to better address the two commercial equipment applications within the work group’s scope: (1) Electric Vehicle Service Equipment (EVSE) and (2) Watthour Type Electric Meters (WHE).
EVSE DRAFT Examination Procedure Outline (EPO)
In December 2015 Draft EPO 30 was distributed as a starting point for the Test Procedure Subcommittee and EVSE Subgroup discussions. An EPO includes the minimum recommended procedures to be used in official inspection and testing of commercial weighing and measuring equipment. The EPO is intended for routine test and inspection of an EVSE by officials/service industry to compliance with HB requirements. NIST developed EPO 30 based on device design, performance, test, operation requirements in NIST Handbook 44 Sections 1.10. General Code, 3.40. Electric Vehicle Fueling Systems – Tentative Code, and 5.55 Timing Devices. Please note that no meeting date has been established for the start of discussions about Draft EPO 30.
The National Conference on Weights and Measures (NCWM) is sponsoring a National Type Evaluation Program (NTEP) Work Group (WG) that will develop an NCWM Publication 14 Checklist for EVSE devices based on NIST Handbook 44 Sections 1.10, 3.40, and 5.55. The NTEP EVSE WG is chaired by Andrei Moldoveanu (NEMA) and report to the NTEP Committee (a subgroup of the NCWM BOD) and the NCWM Board of Directors (BOD). NTEP EVSE WG representatives were recruited from NTEP laboratories/evaluators, EVSE experts, test equipment experts, the Federal Government and a technical industry association. The EVSE Device Checklist must be first evaluated and then certified by NTEP.
|Next Meeting:||Face-to-face meeting (teleconference/web available) of the USNWG Watthour Meter Subgroup May 1 – 3, 2018, Sacramento, CA. Contact Lisa Warfield for additional details at 301-975-3308 or firstname.lastname@example.org|
|Teleconference/Web Meeting; Watthour Type Electric Meters Subgroup – November 16, 2017 - Time -12:30 p.m. to 5:30 p.m. (EST) Contact Lisa Warfield for additional details at 301-975-3308 or email@example.com|
|Face to face meeting of the New Watthour Type Electric Meters Subgroup September 12-14, 2017, Sacramento, CA|
|USNWG Operating Guidelines:|
For meeting summaries from June 11, 2013 up through July 6, 2016 please send a request to the USNWG Contact listed below
For meeting agendas from January 7-8, 2014 up through July 6, 2016 please send a request to the USNWG Contact listed below
|Latest Codes:||NIST Handbook 130 (2017) Method of Sale Regulation for Electricity Sold as Vehicle Fuel|
Development of International Standards: During the October 2016 15th International Conference of the 51st CIML the approval of a new project in TC 12 Instruments for measuring electrical quantities, the revision of R 46(2012) to be conducted as specified in the project proposal addendum 220.127.116.11 to consider retitling the recommendation and address new and different technology and applications.
- OIML R 46-1/-2 (2012) Active electrical energy meters. Available on the OIML website at: https://www.oiml.org
- Part 1: Metrological and technical requirements
- Part 2: Metrological controls and performance tests