(1) Each utility shall have available one or more watthour meters to be used as basic reference standards. The watthour meters must have an adequate capacity and voltage range to test all portable standards used by the utility and must meet the requirements described in subsection 25-6.055(1), F.A.C.
    (a) Watthour meters used as basic reference standards shall not be in error by more than plus or minus 0.05 percent at 1.00 power factor or by more than 0.10 percent at 0.50 power factor. Watthour meters shall not be used to check or calibrate portable standard watthour meters unless the basic reference standard watthour meter has been checked and adjusted, if necessary, to the prescribed accuracy within the preceding twelve months.
    (b) The percent registration of each basic reference standard watthour meter shall be compared with the percent registration of all other basic reference standard watthour meters used by the utility.
    (2) Each utility shall establish traceability of its watthour standard to the national standards at least annually using one of the following methods:
    (a) Through the Measurement Assurance Program (MAP) in which the National Institute of Standards and Technology (NIST) has provided a transport standard; or
    (b) Through a transport standard which is of the same nominal value and of quality equal to the basic reference standards that are sent to NIST or to an independent laboratory approved by the Commission.
    (3) If error exceeding that referenced in Fl. Admin. Code R. 25-6.054(1)(a), in the percent registration of a watthour meter used as a basic reference standard is observed in the comparisons in Fl. Admin. Code R. 25-6.054(2)(b), the utility shall investigate the source of the error. If the cause of the error cannot be corrected, use of the watthour meter as a basic reference standard shall be discontinued.
    (4) Each utility shall maintain the following historical performance records for each watthour meter used as a basic reference standard until the meter is no longer in use:
    (a) Comparisons of basic reference standards with national standards; and
    (b) Intercomparisons made with other basic reference standards.
Rulemaking Authority 350.127(2), 366.05(1), 350.127(2) FS. Law Implemented 366.05(1), (3) FS. History-New 7-29-69, Amended 4-13-80, 5-13-85, Formerly 25-6.54, Amended 5-19-97, 10-26-20.