Interlock Application Scheme # 3

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Interlock Application - Switch and Breaker

Scheme # 3
To prevent operation of switch A when breaker B is closed. Circuit cannot be cleared until proper supervisory key is obtained.

Interlock Application Scheme # 3 - Switch and Breaker

Breaker B and switch A shown closed. Key A-1 held in breaker interlock. Key A-2 retained by supervisor.

1.
2.
3.

4.

5.
6.

7.

Obtain key A-2 from supervisor.
Open breaker.
Insert key A-2 in L-O interlock on breaker B and turn
key A-1 to lock open. key A-2 is now held and key A-1
is free.
Insert key A-1 in L-O-C interlock on switch A and turn
to unlock.
Open switch A.
Turn key A-1 in L-O-C interlock on switch A to lock
open. Key A-1 is now free.
Return key A-1 to breaker interlock and unlock for
operation during service period.

Reverse sequence to restore service.

Links for more interlock application scheme information:

Contents | Introduction | Symbols Legend | Scheme Book

Scheme # 1
Scheme # 2
Scheme # 3
Scheme # 4
Scheme # 5
Scheme # 6
Scheme # 7
Scheme # 8
Scheme # 9
Scheme # 10
Scheme # 10A
Scheme # 11 Scheme # 12

Scheme # 13
Scheme # 14
Scheme # 15
Scheme # 16
Scheme # 17
Scheme # 17A Scheme # 18
Scheme # 19
Scheme # 20
Scheme # 21
Scheme # 22 Scheme # 23
Scheme # 24

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

Scheme # 37
Scheme # 38 Scheme # 39
Scheme # 40
Scheme # 41
Scheme # 42
Scheme # 42A
Scheme # 42B
Scheme # 43
Scheme # 43A
Scheme # 44
Scheme # 45
Scheme # 45A