V-Series Key Interlock
Application Guide
MAIN2
MAIN1
LOR
A1
B1
LOR
B3
A1
B2
A1
A1
A1
LOR
LOAD1
LOAD2
V-Series Key Interlock Application Guide
V-Series Key Interlock Application Guide
Introduction
Legend
Key interlocks are safety devices that provide a lockable
means to limit mechanical movement. They attach to electrical and mechanical devices, such as breakers and switches,
to ensure a safe pre-determined sequence of operations. Key
interlocks are much more flexible than mechanical linkages
and offer the security of a locked position for every operation.
The key may be removed and retained by an operator for absolute security. Typically key interlocks are applied to doors
of switchgear cells and cubicles, racking and operating mechanisms, and are used in a variety of combinations to ensure
a proper sequence of operations.
Key Interlock
Key
Switch (Open)
Switch (Closed)
This guide shows several generic applications where V-Series Key Interlocks can be used. For simplicity sake other
items normally found in a network, such as transformers,
have been left off of the diagrams. Caution must be used to
ensure that an unsafe condition can not occur. The system
designer must thoroughly check any interlocking
scheme to be sure that the system operates as desired.
Circuit Breaker
A1
A1
There are several types of V-Series Key Interlocks available
to accommodate your mounting and interlocking requirements. The basic interlock consists of a lock cylinder mounted
in a brass housing driving a brass bolt. Various combinations
of locks and options are available to extend the basic operation of the interlocks. The options include: keying options,
custom bolt lengths, multi cylinders and electrical auxiliaries.
A key interchange code is used to indicate cylinders operated
by the same key.
A2
Key Interchange Number
Apartment Keyed Cylinder
(operated by Key A1 or A2)
Direction of key travel
Fuse
For more detailed information on V-Series Key Interlocks,
please refer to publication F0106BR9701EP R0
Application Examples:
Compartment
1 - 10 Single Source Applications.
11 - 16 Multi Source Applications.
Multicylinder Lock
LOC
Device Lockable in Open or Closed Position
LO
LC
Device Lockable in Open Position Only
Device Lockable In Closed Position Only
R
Key Removable in Locked Position
H
Key Held in Locked Position
D
Door Lock
Example:
LOH
08/98
A1
B1
Breaker B1 lockable in open
position, key A1 is held in lock.
1
V-Series Key Interlock Application Guide
One:
Interlocking to prevent a switch SW1 from opening when a
breaker B1 is closed
• SW1 and B1 Closed. Key (A1) captive in B1 interlock:
MAIN
De-energize B1.
Turn (A1) to lock B1 in de-energized state.
(A1) is released.
Transfer (A1) to SW1, turn to unlock.
(A1) is captive.
De-energize SW1.
LCR
A1
SW1
A1
LOR
A1
B1
Reverse operations to restore normal service.
LOAD
Two:
Interlocking to prevent a switch SW1 from operating when a
breaker B1 is closed. The breaker may be re-closed for servicing when the switch is locked in the open position.
• SW1 and B1 Closed. Key (A1) captive in B1 interlock
MAIN
De-energize B1.
Turn (A1) to lock B1 in de-energized state.
(A1) is released.
Transfer (A1) to SW1, turn to unlock. (A1) is captive.
LOCR A1
SW1
De-energise SW1.
Turn (A1) to lock SW1 in de-energized state.
(A1) is released.
Transfer (A1) to B1, turn to unlock.
A1
LOR
A1
B1
B1 can now be operated for servicing.
Reverse operations to restore normal service.
LOAD
2
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V-Series Key Interlock Application Guide
Three:
Interlocking to prevent a switch SW1 from operating when a
breaker B1 is closed. A supervisory key is required for additional security.
• SW1 and B1 Closed. Supervisory key (A1) held by supervisor. Key (A2) captive in B1 interlock
Obtain supervisor key (A1).
MAIN
De-energize B1.
Turn (A1) and (A2) to lock B1 in de-energized
state. (A1) is captive, (A2) is released.
LOCR A2
SW1
Transfer (A2) to SW1, turn to unlock SW1.
(A1) is captive.
A2
De-energize SW1.
LO
Turn (A2) to lock SW1 in de-energized state.
(A2) is released.
Transfer (A2) to B1, turn to unlock.
A1
A2
H
R
B1
LOAD
A1
B1 can now be operated for servicing.
Reverse operations to restore normal service.
Four:
Interlocking to prevent a grounding switch SW2 from closing
when the main switch SW1 is closed.
• SW1 is closed and SW2 is open. Key (A1) captive in SW1
interlock
MAIN
De-energize SW1.
A1
LOR
SW1
Turn (A1) to lock SW1 in de-energized state.
(A1) is released.
LOAD
A1
Transfer (A1) to SW2, turn to unlock. (A1) is captive.
Energize SW2.
LOR
A1
SW2
Reverse operations to restore normal service.
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3
V-Series Key Interlock Application Guide
Five:
Interlocking to prevent a switch SW1 from operating when a
breaker B1 is closed. The Breaker may be reclosed for servicing when the switch is locked in the open position. Also to prevent access to a fuse compartment when SW1 is closed.
• SW1, B1 and fuse compartment are closed. Key (A1)
captive in B1 interlock and key (A2) is captive in SW1
interlock.
MAIN
To Service Breaker
De-energize B1.
LOCR
A1
SW1
Turn (A1) to lock B1 in
de-energized state. (A1) is
released.
LOR
A2
A2
Transfer (A1) to SW1, turn to
unlock. (A1) is captive.
De-energize SW1.
LCR
D
A2
To Access Fuse
Compartment
A1
Turn (A1) to lock SW1 in
de-energized state. (A1) is
released.
Turn (A2) to lock SW1 in
de-energized state. (A2)
is released.
Transfer (A1) to B1, turn to
unlock.
Transfer (A2) to interlock
on fuse compartment.
LOR
B1
A1
LOAD
B1 can now be operated
for servicing.
Turn to unlock fuse compartment. (A2) is captive.
Reverse operations to
restore normal service.
Open fuse compartment.
Reverse operations to
restore normal service.
4
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V-Series Key Interlock Application Guide
Six:
Interlocking to prevent a switch SW1 from operating when
breakers B1, B2, B3 are closed. The breakers may be opened
in any sequence.
• SW1, B1, B2 and B3 are Closed. Key (A1) captive in
Transfer block. Keys (A2), (A3) and (A4) are captive in
breaker interlocks.
MAIN
De-Energize B1, B2 and B3.
LOCR A1
SW1
Turn keys (A2, 3, 4) to lock breakers
in de-energized state. (A2, 3, 4)
are released.
LOR
B1
A2
LOR
A3
B2
LOR
A4
B3
Transfer keys to Muticylinder block
and turn.
A3
A2
LOAD1
Turn (A1) and remove. (A2, 3, 4) are
captive.
A4
A3
A2
A4
LOAD2
LOAD3
A1
A1
Transfer (A1) to SW1, turn to unlock.
(A1) is captive.
De-energize SW1.
Turn (A1) to lock SW1 in de-energized
state. (A1) is released.
Transfer (A1) to Multicylinder block.
Turn to release (A2, 3,4).
(A1) is captive.
Transfer (A2,3,4) to breakers and
unlock so breakers can be operated
during servicing.
Reverse operations to restore normal
service.
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5
V-Series Key Interlock Application Guide
Seven:
Interlocking to prevent a switch SW1 from operating when
breakers B1, B2, B3 are closed. The breakers must be
opened in sequence.
• SW1, B1, B2, and B3 are Closed. Key (A1) is captive in
interlock in B1. Key (A2) is captive in interlock on B2. Key
(A3) is captive on interlock on B3.
De-energize SW1.
Turn (A1) to lock SW1 in de-energized
state. (A1) is released.
De-energize B3.
Transfer (A1) to B1, turn to unlock. (A1)
is captive, (A2) is released.
Turn key (A3) to lock B3 in de-energized state. Key (A3) is released.
B1 can now be operated for service.
Transfer key (A3) to B2, turn to unlock.
(A3) is captive, (A2) is released.
Transfer (A2) to B2, turn to unlock. (A2)
is captive, (A3) is released.
De-energize B2.
B2 can now be operated for service.
Transfer key (A2) to B1, turn to unlock.
(A2) is captive, (A1) is released.
Transfer (A3) to B3, turn to unlock, (A3)
is captive.
De-energize B1.
B3 can now be operated for service.
Transfer key (A1) to SW1, turn to
unlock. (A1) is captive.
Reverse operations to restore normal
service.
MAIN
LOCR A1
LO
A1
A2
R
H
B1 LO
A3
R
H
B2
A2
A1
LOAD1
6
A2
SW1
LOR
A3
B3
A3
LOAD2
LOAD3
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V-Series Key Interlock Application Guide
Eight:
Interlocking to prevent two switches SW1 and SW2 from operating when a breaker B1 is closed. Breaker may be closed
for service when switches are locked open.
• Breaker B1, Switches SW1 and SW2 are closed. One
Key (A1) is captive in interlock on B1. Second Key (A1) is
captive in SW2. Key (A2) is captive in SW1.
De-energize B1.
Turn (A1) to lock B1 in de-energized
state. (A1) is released.
MAIN
LOR
Transfer (A1) to SW1, turn to unlock.
(A1) is captive.
A2
SW1
LCR
De-energize SW1.
A1
A1
A2
Turn (A2) on SW1 to lock in de-energized state. (A2) is released.
LOR
A1
Transfer (A2) to SW2, turn to unlock.
(A2) is captive.
De-energize SW2.
B1
A1
LOR
A1
SW2
LCR
A2
Turn (A1) on SW2 to lock in de-energized state. (A1) is released.
LOAD
Transfer (A1) to B1, turn to unlock.
B1 can now be operated for servicing.
Reverse operations to restore service.
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7
V-Series Key Interlock Application Guide
Nine:
Interlocking to prevent two switches SW1 and SW2 from operating when a breaker B1 is closed. Also to prevent breaker
compartment from opening while switches are closed.
• SW1, SW2, B1 and compartment door are all closed. Key
(A1) is captive in B1. Key (A2) is captive in SW1. Key (A1)
and (A3) are captive in SW2
De-energize B1.
MAIN
Turn (A1) on B1 to lock in de-energized state.
(A1) is released.
LOR
A2
SW1
LCR
Transfer (A1) to SW1. Turn to unlock. (A1) is captive.
A1
A1
A2
De-energize SW1.
LOR
Turn (A2) on SW1 to lock in de-energized state.
(A2) is released.
LCR
D
B1
A1
A3
A3
A1
Transfer (A2) to SW2. Turn to unlock. (A2) is captive.
LO
De-energize SW2.
A1
A3
R
R
LCR
SW2
A2
Turn (A3) and (A1) on SW2 to lock in de-energized
state. (A1) and (A3) are released.
LOAD
Transfer (A1) to B1, turn to unlock.
B1 can now be operated for servicing.
Transfer (A3) to interlock on compartment door.
Turn to unlock. (A3) is captive.
Compartment can now be opened.
Reverse operations to restore service.
8
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V-Series Key Interlock Application Guide
Ten:
•
Interlocking to prevent two switches SW1 and SW2, and a bypass switch SW3 from operating under load. Allows by-pass
SW3 to close before B1 is opened and allows breaker to open
with by-pass opened.
.
SW1, SW2 and B1 are closed. SW3 is open. Keys (A1)
and (A4) are captive in B1, Key (A2) is captive in SW1.
Key (A3) is held by a supervisor
Obtain supervisory key (A3).
Transfer (A1) and (A3) to SW1, turn to unlock.
(A1) and (A3) are captive.
Insert (A3) in B1. Turn to lock in energized state.
(A3) is captive, (A4) is released.
De-energize SW1.
Transfer (A4) to SW3, turn to unlock. (A4) is captive.
Turn (A2) on SW1 to lock in de-energized state.
(A2) is released.
Energize SW3.
Transfer (A2) to SW2, turn to unlock. (A2) is captive.
Turn (A4) to lock SW3 in energized state. (A4) is
released.
De-energize SW2.
Turn (A1) on SW2 to lock in de-energized state.
(A1) is released.
Transfer (A4) to B1, turn to unlock. (A4) is captive,
(A3) is released.
To open SW1,
SW2 and B1
while SW3 is
de-energized
begin here
De-energize B1.
Transfer (A1) to interlock on B1. Turn to unlock.
(A1) is captive.
Turn (A1) on B1 to lock in de-energized state.
(A1) is released.
B1 can now be operated for servicing.
Reverse operations to restore service.
MAIN
LOR
A2
SW1
LC
A1
R
A3
R
A1
A3
A2
LOR
A1
B1
LC
A4
A3
R
H
LOCR
A4
SW3
A4
A3
A1
LOR
A1
SW2
LCR
A2
LOAD
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9
V-Series Key Interlock Application Guide
Eleven:
Interlocking to prevent two switches SW1 and SW2 from paralleling separate sources.
• SW1 is closed. SW2 is open. Key (A1) is captive in SW1.
De-energize SW1.
MAIN
AUXILLIARY
Turn key (A1) on SW1 to lock in deenergized state. (A1) is released.
LOR
Transfer (A1) to SW2, turn to unlock.
(A1) is captive.
Energize SW2.
A1
SW1
LOR
A1
SW2
A1
LOAD
Reverse operations to restore service.
10
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V-Series Key Interlock Application Guide
Twelve:
Interlocking to prevent two switches SW1 and SW2 from paralleling separate sources. SW1 and SW2 can not be operated
while breaker B1 is closed.
•
SW1 and B1 are closed. SW2 is open. Key (A1) is captive in B1 and Key (A2) is captive in SW1
.
To Transfer from Main to Auxiliary Supply
De-energize B1.
Turn (A1) on B1 to lock in de-energized state.
(A1) is released.
Transfer (A1) to SW1, turn to unlock.
(A1) is captive.
De-energize SW1.
To Service B1
Turn (A1) and (A2) in interlocks on SW1 to lock in
de-energized state. (A1) and (A2) are released.
Turn (A1) on SW1 to lock in de-energized state.
(A1) is released.
Transfer (A1) and (A2) to interlocks on SW2. Turn
keys to unlock. (A1) and (A2) are captive.
Transfer (A1) to B1, turn to unlock. (A1) is captive.
Energize SW2.
B1 can now be operated for servicing.
Turn (A1) on SW2 to lock in energized state.
(A1) is released.
Reverse operations to restore service.
MAIN
AUXILLIARY
Transfer (A1) to B1, turn to unlock. (A1) is captive.
A2
Energize B1.
LOR
LOR
A2
Reverse operations to return to Main supply.
LOCR
A2
SW1
LOCR
A1
SW2
A1
A1
LOR
A1
B1
LOAD
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11
V-Series Key Interlock Application Guide
Thirteen:
Interlocking to prevent paralleling of separate sources. Loads
can be supplied from either source.
• Main breakers B1 and B2 are closed. Tie breaker B3 is
opened. Keys (A1) are captive in B1 and B2.
Transfer Load 2 to
breaker B1
Transfer Load 1 to
breaker B2
De-energize B2.
De-energise B1.
Turn (A1) on B2 to lock in
de-energized state. (A1)
is released.
Turn (A1) on B1 to lock in
De-energised state. (A1)
is released.
Transfer (A1) to B3, turn
to unlock. (A1) is captive.
Transfer (A1) to B3, turn
to unlock. (A1) is captive.
Energize B3 to connect
Load 2.
Energize B3 to connect
Load 1.
Reverse operations to
restore service.
Reverse operations to
restore service.
MAIN2
MAIN1
LOR
A1
B1
LOR
B3
A1
B2
A1
A1
A1
LOR
LOAD1
12
LOAD2
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V-Series Key Interlock Application Guide
Fourteen:
Interlocking to prevent paralleling of separate sources. Loads
can be supplied from either source. Also to prevent Main disconnect from operating when Main breaker is closed.
• Main devices SW1, SW2, B1 and B2 are closed. Tie
Breaker B3 is open. Keys (A1) and (A2) are captive in
interlock on B1. Keys (A1) and (A3) are captive in interlock on B2
Transfer Load 2 to breaker B1
De-energize B2.
Turn (A1) on B2 to lock in
de-energized state. (A1)
and (A3) are released.
To Service B2
Transfer (A1) to B3, turn
to unlock. (A1) is captive.
MAIN1
Transfer (A3) to SW2,
turn to unlock. (A3) is
captive.
LOCR
Energize B3 to connect
Load 2.
LOCR A3
SW1
A2
SW2
A3
De-energize SW2.
LO
Reverse operations to
restore service.
A2
MAIN2
A2
A1
R
R
Turn (A3) on SW2 to lock
in de-energized state.
(A3) is released.
B1
LO
A3
A1
R
R
B3
B2
A1
A1
A1
Transfer (A3) to B2, turn
to unlock. (A3) is captive.
B2 can now be operated
for service.
LOR
LOAD1
LOAD2
Reverse operations to
restore service.
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13
V-Series Key Interlock Application Guide
Fifteen:
Interlocking to prevent paralleling of separate sources. Loads
can be supplied from either source. To prevent Main disconnect form operating when Main breaker is closed. To prevent
access to a fuse compartment if the Main disconnect and
breaker are closed.
•
•
•
Main devices SW1, SW2, B1 and B2 are closed. Tie
Breaker B3 is open. Keys (A1) and (A2) are captive in
interlock on B1. Keys (A1) and (A4) are captive in interlock on B2.
Key (A3) is captive in interlock on SW1
Key (A5) is captive in interlock on SW2.
Transfer Load 2 to Breaker B1
De-energize B2.
Turn (A1) on B2 to lock in de-energized
state. (A1) and (A4) are released.
To Service B2
Transfer (A1) to B3, turn to unlock.
(A1) is captive.
Transfer (A4) to SW2, turn to unlock.
(A4) is captive.
Energize B3 to connect Load 2.
De energize SW2.
Reverse operations to restore service.
Turn (A4) on SW2 to lock in de-energized
state. (A4) is released.
To Access Fuse Compartment
Between SW2 & B2
Transfer (A4) to B2, turn to unlock. (A4) is
captive.
Turn (A5) on SW2 to lock in de-energized
state. (A5) is released.
B2 can now be operated for service.
Transfer (A4) and (A5) to interlock on
fuse compartment. Turn to unlock. (A4)
and (A5) are captive.
Reverse operations to restore service.
Fuse compartment can now be opened.
MAIN1
MAIN2
Reverse operations to restore service.
LOCR
LOCR
A2
A4
SW2
SW1
LOR
LOR
A3
A3
A5
A5
LC
A2
A3
LC
A4
A5
D
R
R
D
R
R
LO
A4
A1
R
R
A2
A4
LO
A2
A1
R
R
B1
B3
B2
A1
A1
A1
LOR
LOAD1
14
LOAD2
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V-Series Key Interlock Application Guide
Sixteen:
Interlocking to prevent the paralleling of three mains. Loads
can be supplied form any source.
• B1, B2, and B3 are closed. B4 and B5 are open. Key (A1)
is captive in B1, (A2) is captive in B2 and (A3) is captive
in B3. Tie B4 is apartment keyed for (A1) and (A2). Tie B5
is apartment keyed for (A2) and (A3).
Transfer Load 1 to Breaker B2
De-energize B1.
Turn (A1) on B1 to lock in de-energized
state. (A1) is released.
Transfer (A1) to B4, turn to unlock.
(A1) is captive.
Energize B4 to connect Load 1.
Transfer Loads 1 and 2 to B3
Reverse operations to restore service.
De-energize B2.
Turn (A2) on B2 to lock in de-energized state. (A2) is released.
MAIN1
MAIN3
MAIN2
Transfer (A2) to B5, turn to unlock.
(A2) is captive.
Energize B5 to connect Loads 1
and 2.
LOR
A1
B1
LOR
B4
A2
B2
LOR
B5
A2
A3
B3
Reverse operations to restore
service.
A3
A1
A1
A2
A2
A3
LOR
LOAD1
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LOR
LOAD2
LOAD3
15
Schneider Electric
Schneider Electric
19 Waterman Avenue
Toronto, Ontario M4B 1Y2
www.schneider.ca
Tel: (416) 752-8020
Fax: (416) 752-8944
F0106AB9801EP R0
© 1998 Schneider Canada, All Rights Reserved
August, 1998