What are the mandatory safety devices on an elevator?

Safety devices on an elevator are defined by ASME A17.1/CSA B44:

Mandatory devices:

• Safety gear: Mechanical device that stops the cab in case of cable breakage or overspeed. Two types: instantaneous (sudden stop, for speeds < 0.6 m/s) and progressive (smooth stop, for speeds > 0.6 m/s). Periodically tested with a proof load
• Overspeed governor: Detects cab overspeed (typically 115-130% of rated speed) and triggers the safety gear. A steel cable connects the governor to the safety gear. The decision is purely mechanical — no electronics
• Door interlock: The cab cannot move if landing doors are not locked. Electrical contacts of the locks are in series — a single open lock prevents all movement
• Safety brake: Spring-loaded mechanical brake on the traction sheave. Activates automatically in case of power failure
• Emergency stop button: Inside the cab, immediately stops the elevator

Inspections: Safety devices must be inspected monthly by a mechanic and annually by an RBQ inspector.