Scheme L

This scheme is used to prevent the paralleling of lines #1 and #2; performing the operation of switches #1 and #2 under no-load conditions.

Initial conditions: Line #2 supplies load #1 through switch #2 which is normally locked closed with interlock key "B" captive in its lock open position interlock; breaker #1 is closed with its "A" key captive in its respective key interlock. Switch #2 is locked open with no interlock keys present.

Switching scenario: Switching load #1 to line #1: Open and lock breaker #1 thereby releasing the "A" key. Use the "A" key in the switch #2 LOC key interlock to release the switch for operation and move the switch to the open position and lock thereby releasing the "A" and "B" key. Use the "A" key to release switch #1 for operation and move the switch to the closed position thereby trapping the "B" key while releasing the "A" key; use the "A" key to unlock and close breaker #1. 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