This was basically the first lesson in automation class, which made an impact at the time.
A safety switch should be normally closed, energizing a normally open relay, such that any broken cables or connections would be like hitting the switch, causing the relay to de-energize, subsequently cutting power to the main circuit.
A safety switch should be normally closed, energizing a normally open relay, such that any broken cables or connections would be like hitting the switch, causing the relay to de-energize, subsequently cutting power to the main circuit.