Password-protected circuit breaker to protect maintenance workers

The problem

Many maintenance workers suffer fatal electric shocks, usually not from a technical error but from poor coordination: a worker may be up the pole while someone at the substation restores power, unaware anyone is on the line. A call can drop or a note can be forgotten, but a password-protected lock only opens for its owner.

How it works

1. OrderThe worker enters their own password on the unit before starting work.
2. DisconnectThe system disconnects the requested line and locks it in the worker's name.
3. LockAny attempt to restore power is refused while the lock is active.
4. DisplayThe display and the substation dashboard show each line's status: open, or locked with the name of who locked it.
5. OpeningWhen the work is done, the same worker enters the password to unlock the line.
6. LoggingEvery disconnect and reconnect is logged with its time and who did it.

Project features

• It genuinely protects lives — one of the strongest topics you can present to a committee.
• It builds on the personal lockout principle used in industry worldwide, so the idea rests on a sound basis.
• The log settles responsibility: who cut the power, who restored it, and when.
• A clear live demo: try to restore the power and watch the system refuse.
• It can expand to cover several lines and several workers at the same time.

Expected challenges

These are the main obstacles to expect during the build, laid out clearly so you know them before you start.

• Dealing with high voltage — the most dangerous part, requiring proper insulation.
• Safe state on power loss: the lock must stay in place.
• Nobody should be able to bypass the lock by restarting the board.
• Passwords must be stored encrypted, not in plain text.
• For emergencies, a documented, logged bypass path is needed that isn't available to everyone.

The consultation gives you a solution for each one.

Expected committee questions

Prepare your answers in advance: these questions come up often in defenses of similar projects.

1. What happens if the worker forgets the password while up the pole?
2. How do you verify the line is actually disconnected, not just that the relay is open?
3. How does the system handle more than one worker on the same line?
4. How is the password protected from guessing?

Practice the defense, question by question