Additional information:
The 13.8kV vacuum circuit breaker has a line side disconnect. It is a "packaged" interlocked installation. Opening the disconnect while the breaker is closed will trip the breaker prior to the disconnect blades opening. In addition closing of the circuit breaker is not possible unless the it's integral line side disconnect is closed.
there is a viewing window on all disconnects to ensure that these disconnect blades have actually opened when the disconnect operating handle has been operated. This is required by MSHA 30 CFR ยง 56.12006.
