(a)  Each utility furnishing metered electric service shall, unless specifically excused by the Commission, provide and have available such meter laboratory, standard meters, instruments and facilities as may be necessary to make the tests required by these rules, together with such portable indicating electrical testing instruments, watt hour meters, and facilities of suitable type and range for testing service watt hour meters, voltmeters and other electrical equipment, used in its operations, as may be deemed necessary and satisfactory to the Commission.

(b)  All portable indicating electrical testing instruments such as voltmeters, ammeters and watt hour meters, when in regular use for testing purposes, shall be checked against suitable reference standards periodically, and with such frequency as to insure their accuracy whenever used in testing service meters of the utility.