Technical Data Bulletin

Class 3100 Heavy Duty Safety Switches
• Open the circuit beaker
• Turn key A-1 in the L-O-R interlock on circuit breaker B to lock open; Key A-1
is now free
• Insert key A-1 in the L-O-C-R interlock on switch A and turn to unlock
• Open switch A; Key A-1 is now held
• Turn key A-1 in the L-O-C-R interlock on switch A to lock open; Key A-1 is
now free
• Return key A-1 to circuit breaker interlock and unlock for operating during
servicing period
• Reverse the sequence to restore service
4. To prevent paralleling of lines A and B; two loads, fed from either source
(Main-Tie-Main):
Figure 4 - Sample Application
L-O-R
C
L-O-R
A
A
NM
A 1
L-O-R
A 1
A-1
B
B
Circuit breaker A is closed to supply load M. Circuit breaker B is closed to supply
load N. Tie-circuit breaker C is open. Keys A-1 and held in interlocks on both
circuit breakers A and B. Tie-circuit breaker C cannot be closed unless either A or
B is locked open.
To transfer load N to circuit breaker A, proceed as follows:
• Open circuit breaker B
• 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-O-R interlock on tie-circuit breaker B and turn to unlock;
Key A-1 is now held
• Close tie-circuit breaker C
• Reverse the sequence to restore service
• Load M can be supplied through circuit breaker B in a similar manner
38 3100CT1602