Technical Data Bulletin

© 2019 Schneider Electric
All Rights Reserved
2-25
schneider-electric.us
Key Interlock Systems—Factory Installed
Only
Enclosures
Class 736, 1130
Key Interlock Systems for Circuit Breaker Enclosures
(Factory installed only.)
Interlocks are used to prevent the authorized operator from making an unauthorized
operation. Available only on NEMA 4, 4X, 5, 12K, and 12/3R circuit breaker enclosures.
The key interlock system is a simple and easy method of applying individual key interlock
units and assemblies to the above equipment so as to require operation in a
predetermined sequence. UL Listed.
Quoting
Contact local Field Sales office for catalog number, availability and pricing prior to
quoting a job.
Ordering
Order cannot be released for production until the following information has been
provided:
•
End User—Company name, address
•
Function of each lock (e.g., circuit breaker to be locked open with key removed, key
held when circuit breaker is closed)
•
Existing Equipment—if circuit breaker is to be interlocked with equipment already on
site, provide brand of existing lock and key number
•
Other New Equipment—if circuit breaker is to be interlocked with new equipment not
yet installed at the site, then provide contact person and phone number so that locks
may be coordinated
•
Additional information may be required upon order entry
. . . . . . . . Device normally open
. . . . . . . . Device normally closed
. . . . . . . . Direction of key transfer
. . . . . . . . Key interchange number
. . . . . . . . Key
Diagram Symbols
A-1 A-2 A-3
Sample Application—1 (See Figure 1)
To prevent two devices from being closed simultaneously.
Figure 1
A-1
A 1
L-O-R L-O-R
A B
A-1
Two devices are shown in Figure 1. In operation they are not closed at the same time.
With the interlocks arranged as shown only one key is required in the interlocking
system. Both devices are shown open, therefore, the key is free. To close any one device
the key is inserted and turned in that particular lock, the key is held in this lock until the
device is again locked open. This simple interlocking sequence lends itself to a multitude
of applications. The procedure is the same for two devices, neither of which is to be
opened at the same time.
Sample Application—2 (See Figure 2)
To prevent opening of switch A when circuit breaker B is closed.
Figure 2
A-1
L-C-R L-O-R
A
B
A 1
Switch A and circuit breaker B are in closed position. Key A-1 is held in circuit breaker B
interlock.
•
Open circuit breaker.
•
Turn key A-1 in L-O-R interlock on circuit breaker B to lock open. Key A-1 is now free.
•
Insert key A-1 in L-C-R interlock on switch A and turn to unlock.
•
Open switch A. Key A-1 is now held. Reverse sequence to restore service.
2
METERING EQUIPMENT
5/15/2019