DOCA0095EN

Locking a Circuit Breaker with a 9421 Rotary Handle

Locking Options for the 9421 Rotary Handle

DANGER
HAZARD OF ELECTRIC SHOCK, EXPLOSION, OR ARC FLASH
When the circuit breaker handle is locked in the O (OFF) position, always use a properly rated voltage sensing device to confirm power is off before working on equipment.
Failure to follow these instructions will result in death or serious injury.

The Class 9421 circuit breaker can be locked in the RESET/LOCK position as follows:

  • With the door closed, by locking the rotary handle in the RESET/LOCK position (the door is also locked)

  • With the door open, by locking the operating mechanism

Locked Position

Lock Type

Lock Characteristics

Accessory

RESET/LOCK

Standard padlocking

Up to 3 padlocks (not supplied)

Diameter 4–8 mm (3/16–5/16 in.)

Inserting Padlocks in the 9421 Rotary Handle

The handle can be locked in the RESET/LOCK position.

No setup is required to lock the handle in the RESET/LOCK position.

Step

Action

Comment

1

With the handle in the RESET/LOCK position, pull the tab under the handle until a space opens below the handle.

2

Insert one or more padlocks in the space.

Locking the Circuit Breaker with a 9421 Rotary Handle in the O (OFF) Position When the Door is Open

To open the enclosure door, the operating mechanism must be in the O (OFF) position. The following figure shows how to lock the circuit breaker itself, instead of the handle.

Overriding the 9421 Door Interlock

DANGER
HAZARD OF ELECTRIC SHOCK, EXPLOSION, OR ARC FLASH
Overriding the door interlock must only be done by qualified electrical personnel.
Failure to follow these instructions will result in death or serious injury.

An interlock between the door and the circuit breaker position allows you to open the door only when the circuit breaker is open and the operating mechanism is in the O (OFF) position.

When the operating mechanism is in the I (ON) position, the door interlock prevents you from opening the door. To open the door, you must turn the handle to the O (OFF) position.

Under exceptional circumstances, qualified electrical personnel can follow these steps to open the door while the rotary handle is in the I (ON) position:

Step

Action

1

Using a screwdriver, turn the locking screw clockwise by 90 degrees.

2

Holding the locking screw in that position, open the door.

NOTE: Follow the same procedure to close the door while the rotary handle is in the I (ON) position.
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