Rule 37 of 40 · Chapter VI — Tools, Habits, and Judgement
Do not work tired, rushed, or alone
Why this rule exists
Electrical safety runs on attention and margin; fatigue, haste, and isolation each strip those away. Tired people skip the verify step; rushed people take the shortcut they should not; a person alone has no one to hit the disconnect or start CPR if a shock locks their muscles. The failure mode usually is not ignorance; it is a competent person cutting one corner on a bad day. Most serious injuries happen not because someone did not know the rule but because conditions pushed them past following it. Manage the conditions, not just the knowledge.
In practice
Never work on live or potentially live systems alone; have a second person present who knows where the disconnect is, how to cut power without touching you, and how to call for help and give CPR. Stop when you are tired, and do not start energized-adjacent work late in a long day. Build in time so you are never racing a deadline with your hands near a conductor. Take breaks, eat, stay hydrated. If you notice yourself skipping steps, that is the signal to stop, not to push through.
When it doesn't apply
Plenty of fully de-energized, verified work is safely done solo; the buddy requirement is strongest for live systems and higher energy. But even then, someone knowing where you are is cheap insurance. No exception makes working alone on a live high-energy system acceptable; if that is the only way it can happen, it should not happen that way.