(a) Not later than the effective date of this system of accounts each Class A and B utility shall begin in the preparation of a continuing property record of operating property used in electric operations, subdivided so as to show separately the operating property located in each city, village, or town. Such record of property acquired prior to the effective date of this system of accounts shall be completed not later than two years after the effective date thereof.

(b) The continuing property record shall be arranged in conformity with the operating property accounts and shall show a description of the property and the original cost (see § 196.1, subd. [a][33]) thereof, except that for such portion of the property, the original cost of which can not be determined without excessive expense, the original cost shall be estimated. In the case of future additions, and so far as reasonably feasible for present property, there shall be shown (either in such continuing property record or in other records referred to therein) for each item of one or more units the date of acquisition (or construction by the accounting utility or any predecessor thereof), the date when first placed in service, the location of the property, and in the case of movable items, the manufacturer's name and any number or other identifying mark imprinted thereon, the number or designation used by the utility, and such other particulars as may be necessary for complete identification. The continuing property record shall show as of the end of each fiscal year, for each prior year's construction, the surviving balance for each continuing property record unit, in terms of both quantities and dollars. Property consisting of a large number of similar items may be grouped and within such groups for each fiscal year the average cost of similar units may be used.

(c) In the case of large items, such as structures, boiler plant equipment, and turbo-generators, the original cost of each unit or group of units comprising a piece of property acquired as a whole, shall be determined when feasible, and otherwise it shall be estimated. In the case of land and structures the original cost of each parcel of land and each structure is sufficient.

(d) The record shall show all essential details and the related costs of equipment in each generating station, substation, transformer station, and transmission line.

(e) Each utility shall file, not later than six months after the effective date of this system of accounts, a statement of the units to be shown separately in the continuing property record. Such units need not be identical with the “Units of Property” to be filed as provided in paragraph (1) of subdivision (b) of section 197.23.