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Interlock Application - Prevent Paralleling of Lines

Scheme # 17A
To prevent paralleling of lines A, B, C, and D. Four loads, fed from any source (three tie-breakers). Also prevents opening of rear access doors when respective breakers are closed.

Breakers A, B, C, and D are closed to supply their respective loads. Keys A-1, B-1, C-1, and D-1 are held in L-O interlocks of breakers A, B, C, and D. Tie-Breakers E, F, and G are locked open. Breaker E interlock has an apartment lock and can be unlocked for operation with either key A-1 or B-1. Breaker F interlock has an apartment lock and can be unlocked for operation with either key B-1 or C-1. Breaker G interlock has an apartment lock and can be unlocked for operation with either key C-1 or D-1. All rear access doors are locked closed. All keys for rear access doors (K-1 through K-9) are held in transfer interlocks.

All loads can be transferred as described in scheme 17.

To open rear access doors K-1, K-2, and K-3:

Reverse sequence to restore service.

To open rear access doors K-4, K-5 and K-6:

Reverse sequence to restore service.

To open rear access doors K-7, K-8 and K-9:

Reverse sequence to restore service.

Scheme # 25
Scheme # 26
Scheme # 27 Scheme # 28
Scheme # 29
Scheme # 30
Scheme # 31
Scheme # 32
Scheme # 33 Scheme # 34
Scheme # 35
Scheme # 35A
Scheme # 36