1. (a) Basic reference standards.

   1. (1) The basic reference standards shall be:

      1. (A) Housed in a temperature-controlled environment; and
      2. (B) Energized continuously.

   2. (2)

      1. (A) Every twelve (12) months at least one (1) basic reference standard (the one (1) with the oldest calibration date) shall be calibrated by an independent standardizing laboratory so that its accuracy is referenced to the National Institute of Standards and Technology.
      2. (B) As an alternative, the basic reference standards shall be compared to a National Institute of Standards and Technology transport standard every twelve (12) months.
   3. (3) Each month, the basic reference standards shall be compared and the results recorded.

2. (b) Laboratory secondary standards.

   1. (1) For testing the accuracy of portable standard watt-hour meters and other portable instruments used for testing service meters, each electric utility shall provide for and have available secondary standards as reference or check standards.

   2. (2) Secondary standards may include any or all of the following:

      1. (A) Electrical instruments;
      2. (B) Watt-hour meters; and
      3. (C) Wattmeters.

   3. (3) Service-type watt-hour meters used as secondary standards shall be:

      1. (A) Permanently mounted in the meter laboratory of the electric utility; and
      2. (B) Used for no other purpose than for checking working watt-hour standards.
   4. (4) Secondary standards shall be compared to a basic reference standard and adjusted, if necessary, every twelve (12) months by an Arkansas Public Service Commission-approved standardizing laboratory.

3. (c) Portable standard watt-hour meters.

   1. (1)

      1. (A)

4. (i) All portable electromechanical standard watt-hour meters shall be compared with secondary standards at least once a month.

   1. (ii) All portable electronic standard watt-hour meters shall be compared with secondary standards at least every six (6) months.

      1. (B) If the comparison shows any portable standard watt-hour meter to be more than plus or minus five percent (5%) in error at any load at which the portable standard will be used, the portable standard watt-hour meter shall be tested, adjusted, and certified in:

         1. (i) The laboratory of the electric utility; or
         2. (ii) Some other independent laboratory.
      2. (C) A certificate or calibration card that shows the date the meter was last certified and adjusted and that is signed by the proper authority must be kept with each portable standard watt-hour meter at all times.
      3. (D) Records of certification and calibration shall be kept on file with the electric utility for a period of at least one (1) year.

   2. (2) Portable standard watt-hour meters that are infrequently used shall be certified or calibrated prior to use.

      1. (d) Portable testing instruments.

   3. (1)

      1. (A) All portable electrical testing instruments such as voltmeters, ammeters, and wattmeters shall be checked and calibrated in accordance with procedures and intervals recommended by the instrument manufacturer.

      2. (B) All instruments used for such purposes shall have:

         1. (i) A manufacturer-stated instrument error no greater than one percent (1%) of full-scale value; and
         2. (ii) No appreciable error at zero reading.
   4. (2) Portable equipment that is infrequently used shall be compared with a standard before using.
   5. (3) For portable equipment used to obtain routine or general operating information, the limits of accuracy as specified in subdivision (d)(1) of this section need not apply, but such instruments shall be within the range of accuracy necessary to obtain reliable data.

Codification Notes: This section was promulgated as Rule 7.04 of the Special Rules — Electric prior to codification in the Code of Arkansas Rules.