Section 57.15. System frequency

(a) Standard frequency. An electric distribution company supplying alternating current service shall adopt and file with the Commission a standard frequency or frequencies for its system, the suitability of which may at any time be determined by the Commission.

(b) Allowable variation. An electric distribution company shall maintain the system frequency within 3% of the standard frequency adopted. Momentary variations of frequency of more than 3%, which are clearly not due to lack of proper equipment or reasonable care on the part of the electric distribution company will not be considered as violations of this section.

(c) Records. An electric distribution company shall continuously monitor and record system frequency variations. The records shall be provided to the Commission on request.

The provisions of this § 57.15 adopted February 25, 1946; amended through May 29, 1973; amended May 21, 1999, effective May 22, 1999, 29 Pa.B. 2667. Immediately preceding text appears at serial page (246378).