Section PSC 113.0920 - Statistical sample testing plan for new self-contained single phase and 3-wire network metersThe new meter sample testing plan described in subs. (1) to (5) may be used for testing new self-contained, single phase and 3-wire network meters without mechanical demand registers or mechanical pulsing devices instead of the new meter test requirements of s. PSC 113.0911(1) (a), if the commission authorizes the adoption of the plan by a utility.
(1) Meters, as received from the manufacturer, shall be divided into homogeneous lots by manufacturers and type. The maximum number of meters in any lot may not exceed 1,000 or be less than 96. From each such lot assembled, there shall be drawn a coded sample size specified in Military Standard 414, (MIL-STD-414) dated 11 June 1957, as shown for the various group sizes using Inspection Level IV of Table A-2 on page 4 and a corresponding actual sample size as shown in Table B-3 on page 45. The sample shall be drawn by a random method that ensures that each meter in the lot has an equal chance of being selected.(2) The test criterion for acceptance or rejection of each lot shall be based on a separate analysis conducted at both the full load and light load test points at unity power factor, as specified in s. PSC 113.0811(1) (c), by means of the Standard Deviation Method, Double Specification Limit and with an Acceptable Quality Level (AQL) of 0.25 for the full load accuracy analysis and an AQL of 0.40 for the light load accuracy analysis as shown in Table B-3, MIL-STD-414, page 45. The statistical analysis calculations shall be made following the example outlined on page 43 of MIL-STD-414 with the upper and lower specification limits U and L designated at 101% and 99% respectively.(3) One non-registering meter may be removed from the sample lot for analysis purposes and replaced with another randomly selected meter. If more than one meter in a sample lot is found not to be registering, the entire lot shall be rejected.(4) A lot shall be deemed acceptable for installation if the total estimated percent defective (P) is less than the appropriate maximum allowable percent defective (M) as determined from Table B-3 under the procedures of sub. (2). All meters in an acceptable lot shall be deemed to have met the accuracy requirements of s. PSC 113.0811 for placement in service without further testing.(5) A lot shall be considered rejected (not acceptable for installation) if the total estimated percent defective (P) is greater than or equal to the appropriate maximum allowable percent defective (M) as determined from Table B-3 under the procedures of sub. (2). All meters in a rejected lot shall be tested and adjusted in accordance with the procedures of s. PSC 113.0811 or replaced with meters meeting these requirements.Wis. Admin. Code Public Service Commission PSC 113.0920
CR Register, July, 2000, No. 535, eff. 8-1-00.