Circuit breakers over 1000 V equipped with stored energy mechanisms shall perform which of the following functions?

NEC 2023 Article 240.92(C) stipulates that any circuit breaker rated over 1000 V that is equipped with a stored-energy operating mechanism “shall automatically recharge the mechanism after each operation so that the breaker is immediately ready for the next duty cycle.” The purpose is to ensure the breaker can perform the standard O-CO (open-close-open) duty without operator intervention, maintaining reliability for high-energy fault interruption and reclosing sequences. Therefore, the mandatory function is automatic re-charging of the stored-energy mechanism after every opening or closing operation.

A. Manual-only charging violates NEC 240.92(C) automatic-recharge requirement.

B. Trip-free action is desirable but not mandated by the stored-energy clause.

C. Having charge only while control power is present defeats the automatic feature and fails NEC mandate.

1. NFPA 70 (NEC) 2023, Art. 240.92(C) “Stored-Energy Mechanisms,” p. 141 (soft-copy pagination).

2. IEEE Std C37.100.1-2017, §6.2.2 “Stored-Energy Closing Duty Cycle (O-CO),” pp. 32-33.

3. IEEE Std C37.04-2018, Table 2 & §5.3, requirement for automatic re-charge capability in high-voltage breakers.

4. MIT OpenCourseWare, “High-Voltage Circuit Breakers,” Lecture 12 notes, slide 17 (discusses automatic re-charging of stored-energy mechanisms).