Summary

This is a simple printable lockout device for use with many common circuit breakers used in the United States and potentially elsewhere. This device has three pieces: a cover, the main body, and the clamp wedge. You will also need three screws (not supplied with this Thing) to complete assembly.

Needed components:
1x M3 screw, 20mm+ in length (clamp)
2x M3 screws, 4-6mm in length (cover to main body)^

The top opening of the main body is wide enough for you to slip the wedge inside the main body. The angled edges should line up, and the flat back with screw opening should face the back of the main body where the center screw hole is present. Thread the longer M3 screw into this screw hole and into the matching hole on the back of the wedge. This will function as the clamp which presses up against the breaker lever.

The other two screws are used in the front section to mount the cover to the main body. ^Alternatively, you could use a piece of 3mm filament heated and peened over on both sides as a retainer for the cover. However, the cover must be able to swing open and closed without obstruction, since this is the mechanism by which the clamp screw will be covered and the lock and tag attached.

Note: This device is designed to reduce risk of injury while performing maintenance on an electrical circuit, but it cannot completely eliminate the risks involved. This device, like many professionally produced lockout devices, can still be forcefully removed or bypassed by a malicious actor. When working on electrical circuits, always maintain the proper electrical safety standards.