Scheme H

This scheme is used to prevent the paralleling of two independent sources through the tie breaker while allowing the switching of sources to the load(s).

Initial Condition: Line #1 feeds load #1 through breaker #1 which is normally closed with its interlock key "A" captive. Line #2 feeds load #2 through breaker #2 which is normally closed with its interlock key "A" captive. Breaker #3 is locked open with no interlock key present.

Switching scenario #1: Line #1 feeding both loads through breaker #1 and breaker #3: Open and lock breaker #2 thereby removing the "A" key. Use the "A" key to unlock and close breaker #3. Reverse to restore the initial condition.

Switching scenario #2: Line #2 feeding both loads through breaker #2 and breaker #3: Open and lock breaker #1 thereby removing the "A" key. Use the "A" key to unlock and close breaker #2. 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