Opening, Closing, Resetting, and Testing the Circuit Breaker

Opening and Closing with the Front Extended Rotary Handle

Task	Action
Open the circuit breaker	Turn the rotary handle from the I (ON) position to the O (OFF) position.
Close the circuit breaker	Turn the rotary handle from the O (OFF) position to the I (ON) position.

Resetting the Front Extended Rotary Handle After a Trip

When the circuit breaker trips, the rotary handle moves from the I (ON) position to the Trip position.

WARNING
HAZARD OF CLOSING ON ELECTRICAL FAULT Do not close the circuit breaker again without first inspecting and, if necessary, repairing the downstream electrical equipment. Failure to follow these instructions can result in death, serious injury, or equipment damage.

The fact that a circuit breaker has tripped does not fix the cause of the fault detected on the downstream electrical equipment.

Follow these steps to reset the circuit breaker after a trip caused by an electrical fault.

Step	Action		Position
1	Turn the handle from the Trip position to the O (OFF) position. The circuit breaker is open.		O (OFF)
2	Take precautions to protect yourself.	–	O (OFF)
3	Look for the cause of the detected fault.	–	O (OFF)
4	Clean and test the downstream equipment and the circuit breaker.	–	O (OFF)
5	Turn the handle from the O (OFF) position to the I (ON) position. The circuit breaker is closed.		I (ON)

Testing the Trip Mechanism

CAUTION
HAZARD OF NUISANCE TRIPPING Circuit breaker tests must only be done by qualified electrical personnel. Failure to follow these instructions can result in injury or equipment damage.

When testing the trip mechanism take precautions against:

Disrupting operations
Activating inappropriate alarms
Triggering unwanted actions

For example, tripping the circuit breaker with the push-to-trip button can lead to inappropriate fault indications or corrective actions (such as switching to an alternate power source).

There is no push-to-trip button on the door of a circuit breaker with a front extended rotary handle. To check the trip mechanism, the door must first be opened.

Follow these steps to test the trip mechanism.

Step	Action	Position
1	With the circuit breaker in the O (OFF) position, open the door.	O (OFF)
2	Turn the circuit breaker from the O (OFF) position to the I (ON) position, using one of the following tools: An open door shaft operator (LV426937). A flat wrench, taking care not to damage the extension shaft or its surface treatment.The extension shaft is a hollow rectangular tube, 15 x 10 mm (0.59 x 0.39 in.). The circuit breaker is ready for the test.	I (ON)
3	Press the push-to-trip button. The circuit breaker trips.	Trip
4	Turn the circuit breaker from the Trip position to the O (OFF) position. The circuit breaker is open.	O (OFF)
5	Close the door.	–