TM9-4120-401-14
4-42. CIRCUIT BREAKER (CB1). - continued
b. Test.
(1) Tag and disconnect wire leads from circuit breaker (1).
Remove six screws (2), bck washers (3), flat washers (4), boot (5), and circuit breaker (1) from unit.
(2)
(3) With circuit breaker (1) in ON position, use multimeter set to measure resistance and check continuity
across terminals LINE and LOAD of each pole. The multimeter must indicate that contacts are closed
(continuity).
(4) With circuit breaker (1) in OFF position, use multimeter set to measure resistance and check continuity
across terminals LINE and LOAD of each pole. The multimeter must indicate that contacts are open
(no continuity).
Replace circuit breaker (1) if it tests defective.
(5)
(6) Secure circuit breaker (1) and boot (5) onto unit using six screws (2), lock washers (3), and flat
washers (4).
(7) Connect wire leads to circuit breaker (1) using tags and wiring diagram (figure 4-6). Remove tags.
c. Replace.
(1) Tag and disconnect wire leads from circuit breaker (1 ).
(2) Remove six screws (2), bck washers (3), flat washers (4), boot (5), and circuit breaker (1) from unit.
Replace boot (5) if damaged.
(3)
(4) Secure new circuit breaker (1) and boot (5) onto unit using six screws (2), lock washers (3), and flat
washers (4).
(5) Connect wire leads to circuit breaker (1) using tags and wiring diagram (figure 4-6). Remove tags.
NOTE
FOLLOW-ON MAINTENANCE:
Install top panel (para 4-11).
Connect power at power source.
4-104
