Lock Dog

This is a design for a lock dog that is attached to a circuit breaker to prevent people from switching the breaker on and re-energising the circuit when the circuit is being worked on.

This particular version is intended for electrical students/apprentices to fabricate by hand from a short length of plastic bar 25mm x 15mm, as part of the their hand skills training.

This is a 3D printed version used to provide a model for the students. It requires a M6 screw to operate. The students usually fabricate the screw from a short length of threaded rod.

NOTE: This is a training device only and is not certified for use outside a training environment. Individuals are responsible for ensuring that any device constructed by them using any aspect of this design:

1. is tested and certified for use, as required, by the relevant authorities in their jurisdiction and
2. has been tested by them and that they have determined that the device is safe to use and that they accept full responsi