N.Y. Comp. Codes R. & Regs. tit. 21, § 454.4
(3) Except as provided in this section, customer shall not permit access by anyone, except authorized representatives of authority or the utility providing delivery and service, to the meter equipment or any other property of authority or the utility providing delivery and service, and shall not interfere or permit interference with such equipment. Customer shall be responsible for their safekeeping on his premises. Duly authorized representatives of authority and the utility providing delivery and service shall have the right to access to the premises of customer and to all appropriate property of authority or the utility providing delivery and service to all reasonable times for the purpose of reading and testing meters, inspecting equipment used in connection with its service, repairing, readjusting, or replacing defective or inaccurate meters, metering the demand, ascertaining and counting the connected load of customer's installation, removing its property, or any other purpose.
(c) Meters errors.
If any of the meter tests provided for in this section discloses that the error of any meter or meters exceeds two percent correction based upon the inaccuracy found shall be made of the records of electric service furnished since the beginning of the monthly billing period immediately preceding the billing period during which the test was made; provided, that no correction shall be made for a longer period than such inaccuracy may be determined by authority to have existed. Any correction in billing resulting from such correction in meter records shall be made in the next monthly bill rendered by authority to customer, and such correction when made shall constitute full adjustment of any claim between customer and authority arising out of such inaccuracy of meters.
(a) Transmission metering.
Unless otherwise specified in the applicable service tariff or other contract documents, the total electric power and energy delivered to customer will be measured alone or in conjunction with deliveries to others by metering equipment to be furnished and maintained by authority. The meter or meters shall be sealed and the seals shall be broken only upon occasions when the meters are to be inspected, tested or adjusted, and representatives of customer shall be afforded reasonable opportunity to be present upon such occasions. The meter or meters shall be tested at least once each year by authority and at any reasonable time upon request therefor by either authority or customer. Any metering equipment found to be defective or inaccurate shall be repaired and readjusted or replaced. Should any meter fail to register, the electric power and energy delivered during the period of failure to register shall, for billing purposes, be estimated by authority from the best information available.
(b) Delivery and service metering.