Scheme O

This scheme is used to prevent the paralleling of any of the lines while allowing the switching of the loads to alternate sources.

Initial conditions: Line #1 supplies load #1 through breaker #1 which is normally closed with its respective interlock key "A" captive. Line #2 supplies load #2 through breaker #2 which is normally closed with its respective interlock key "B" captive. Line #3 supplies load #3 through breaker #3 which is normally closed with its respective interlock key "C" captive. Tie breaker #1, and #2 are locked open with no interlock keys present.

Switching scenario #1 - Switching two loads to one line: Switching load #1(#2) from line #1(#2) to line #2(#1): Open and lock breaker #1(#2) there by releasing the "A"("B") key. Use the "A"("B") key to unlock and close tie breaker #1. Line #2(#1) now supplies loads #1 and #2. The switching of load #2 and #3 is congruous. Reverse to restore the initial condition.

Switching scenario #2 - Switching all loads to one line: Switching load #1, #2 and #3 to line #1: Open and lock breaker #2 thereby removing the "B" key. Open and lock breaker #3 thereby removing the "C" key. Use the "B" and "C" keys to unlock and close tie breaker #1 and #2. The switching to line #2 and #3 is congruous. Reverse to restore the initial condition.

Note: The key interlocks on tie breaker #1, and #2 are dual combinated and can accept two independent keys. This scheme may be extrapolated to N line breakers and N-1 tie breakers.

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