(1) Electrical utilities must provide the commission with a written statement of their practices under these rules covering:

(a) A description of test standards and meter testing equipment, if maintained by the electrical utility;

(b) A description of methods employed to ascertain and maintain the accuracy of the test standards and meter testing equipment, including the frequency of such tests, if the electrical utility chooses to maintain its own such standards and equipment rather than use the services of a certified testing laboratory.

(2) If an electrical utility chooses to maintain its own test standards and meter testing instruments, it must retain records showing the date when each test standard and each meter testing instrument was tested, calibrated, or adjusted. Test standards must not be used in the field as working instruments.