Scheme N

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 #1 feeds load #2 through switch #1 and breaker #1; line #2 feeds load #2 through switch #2 and breaker #2. Switches #1 and #2 are locked closed with no interlock keys present; breakers #1 and #2 are closed with keys "A & C and B & C" captive respectively in their interlock units; the tie breaker is locked open with no key present.

Switching scenario 1: Switching load #1(#2) to line #2(#1): Open and lock breaker #1(#2) thereby releasing the "C" key. Use the "C" key to unlock and close the tie breaker. Reverse to restore the initial condition.

Switching scenario 2: Breaker isolation for testing or servicing: open and lock breaker #1(#2) thereby releasing the "A"("B") key. Use the "A"("B") key to unlock and open switch #1(#2); return key "A"("B") to breaker #1(#2) to unlock and close the breaker for testing or servicing. 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