N.Y. Comp. Codes R. & Regs. tit. 16, § 463.11 – Additions and retirements of steam plant.

(a) For the purpose of avoiding undue refinement in accounting for additions to and retirements and replacements of steam plant, all property shall be considered as consisting of (1) retirement units and (2) minor items of property.
(b) Units of property (i.e., retirement units, see section 460.1[a][36] of this Article). Each utility may adopt its own list of retirement units for the purpose of this instruction until such time as the commission shall prescribe a list of units. Not later than six months after the effective date of this system of accounts, each utility shall file with the commission a list of the items of property it proposes to account for as retirement units of property. Revisions of such list may be made at any time by appropriate filing thereof with the commission.
1. (1) When a retirement unit is added to steam plant, the cost thereof shall be added to the appropriate steam plant account, except that when retirement units are acquired in the acquisition of any steam plant constituting an operating system, they shall be accounted for as provided in steam plant instruction, section 463.3 of this Part.
2. (2) When a retirement unit is retired from steam plant, with or without replacement, the book cost thereof shall be credited to the steam plant account in which it is included, determined in the manner set forth in subdivision (d) of this section. The book cost of the retirement unit retired and credited to steam plant shall be charged to the depreciation reserve provided for such property. (See also account 144, Retirement Work in Progress, and steam plant instruction, section 463.12 of this Part.)
  (c) Minor items of property.
3. (1) When a minor item of property which does not replace a similar item and which is a part of or associated with a retirement unit and will be accounted for and retired together with such unit, and which by itself or together with other similar items makes a substantial addition, is added to the plant, the cost thereof shall be added to the appropriate steam plant account; otherwise the cost of any minor item of property shall be charged to the appropriate maintenance account. The amount added to steam plant accounts for such minor items shall not, however, exceed the additional cost computed at current prices that would have been incurred if the minor items had been installed together with the retirement units to which they are related.
4. (2) When a minor item of property is retired and not replaced, the book cost thereof shall be credited to the steam plant account in which it is included; the depreciation reserve shall be charged with the book cost and cost of removal and credited with the salvage. If, however, the book cost of a minor item retired and not replaced, the original cost of which is less than $100, has been or will be accounted for by its inclusion in the retirement unit of which it is a part when such unit is retired, no separate credit to the property account is required when such minor item is retired.
5. (3) When a minor item of property is replaced independently of the retirement unit of which it is a part, the cost of replacement shall be charged to the maintenance account appropriate for the item, except that if the replacement effects a substantial betterment (the primary aim of which is to make the property affected more useful, more efficient, or of greater capacity), the excess cost due to the betterment shall be charged to the appropriate steam plant account. Such excess cost shall not exceed the additional cost computed at current prices that would have been incurred for such betterment if it had been installed together with the retirement unit to which it is related.
  (d) Determination of book cost.
  The book cost of steam plant retired shall be the amount at which such property is included in steam plant accounts 101 to 104 or 106, including all components of construction costs. The book cost shall be determined from the utility's records and if this can not be done, it shall be estimated. When it is impracticable to determine the book cost of each item, due to the relatively large number or small cost thereof, the average book cost of the items, with due allowance for any differences in size, character, and year of installation, shall be used as the book cost of the items retired.
  (e) Land retired.
  The book cost of land retired shall be credited to the appropriate land account. If the land is sold, the difference between the book cost and the sale price of the land (less commissions and other expenses of making the sale) shall be credited or debited to the appropriate depreciation reserve.
  (f) Steam plant sold.
  When steam plant constituting an operating unit or system is sold, conveyed or transferred to another by sale, merger, consolidation or otherwise, the book cost of the property sold or transferred to another shall be credited to the appropriate steam plant accounts, and amounts carried in account 105, Steam Plant Acquisition Adjustments, shall be credited thereto. The amounts (estimated if not known) carried with respect thereto in the depreciation and amortization reserve accounts and in account 241, Customers' Advances for Construction, and account 265, Contributions in Aid of Construction, shall be charged to such reserves and accounts. Unless otherwise ordered by the commission, the difference, if any, between (1) the net amount of debits and credits and (2) the consideration received for the property (less commissions and other expenses of making the sale) shall be included in account 414, Miscellaneous Debits to Surplus, or account 401, Miscellaneous Credits to Surplus, as appropriate. (See account 106.3, Steam Plant Sold.)
(g) The service value of steam plant retired shall be charged in its entirety to account 250, Reserve for Depreciation of Steam Plant. Any amounts which by approval of the commission are charged to account 141, Extraordinary Property Losses, shall be credited to account 250, Reserve for Depreciation of Steam Plant.
(h) The ledgers containing the primary steam plant accounts and subdivisions thereof shall be kept so as to show on their face (1) additions, (2) retirements, and (3) transfers and adjustments. Corrections of errors and adjustments to additions or retirements in the current or preceding year shall be classified as additions or retirements.
(i) The cost of paving disturbed, including replacing pavement, pavement base and sidewalks, shall be included in the steam plant accounts only when incurred in connection with the addition of one or more retirement units of property; and the cost associated with a particular retirement unit (see, however, subd. [d], supra) shall be retired when that retirement unit is retired, irrespective of whether the paving itself has a shorter or longer life. No addition (except charges to land for public improvements) shall be made to any steam plant account for cost of paving installed in public streets which is not directly occasioned by the installation of property constituting one or more retirement units with which the paving cost is associated as an element of cost. Amounts for such cost of pavement which are included in any primary steam plant account or subdivision thereof shall be carried in a separate subdivision of the account so that the balance therein may be determined at any time.
(j) In the case of substantial items of equipment readily identifiable by serial number or other distinguishing mark, such as pumps, motors, meters, vehicles, furniture, etc., which are retired from plant and not sold or scrapped, statistical records shall be maintained to show readily the year of original entry into utility service and the year when permanently retired and the salvage realized at permanent retirement. Such statistical records shall be of such nature that the history of the property may be recast to reflect the total life and final salvage of such items and to eliminate the intermediate retirements and reuses, during the life of the property as well as after final retirement.