Scheme B1

This scheme is used to prevent the opening of the non-load break disconnect switch while the breaker is closed; insuring the disconnect switch is locked open before the breaker can be re-closed for testing or servicing.

Initial Condition: The load is fed from Line 1 through no-load disconnect switch #1 and Breaker #1. Switch #1 is locked closed with no interlock key present in its LC position key interlock, switch #1 has a "B" key captive in its LO position key interlock. Breaker #1 is closed with its respective interlock key "A" captive.

Opening the non-load break disconnect switch and servicing/testing the breaker: Open and lock Breaker #1 thereby releasing the "A" key. Use the "A" key to unlock and open Switch #1. Lock Switch #1 in the open position thereby removing the "B". Use the "B" key to unlock and re-close Breaker #1 for servicing/testing. Reverse to restore the initial condition.

Additional Schemes:
A / A1 / B / B1 / C / D / E / F / G / H / H1 / H2 / K / L / M / N / O / P / R / U.P.S. System / Capacitor Bank Access Scheme