IEC 60073: Coding of Indicating Devices by Colours — Making Safety Visible

Red Means Danger: How IEC 60073 Color Coding Prevents Control Room Misoperation

IEC 60073:2002 specifies color-coding for indicator lights and push-buttons. In a substation control room, operators must interpret hundreds of indicators instantly — standardized color coding is the final safeguard against misoperation.

Standard color definitions: RED = Emergency/Fault/Stop, YELLOW = Abnormal/Warning/Intervention, GREEN = Safe/Normal, BLUE = Mandatory Action, WHITE/GREY = Neutral/Undefined. Flashing (1.4–2.8 Hz) is reserved for conditions requiring immediate attention — such as auto-reclose lockout after a protection trip.

Why colors cannot be arbitrary: An operator color-meaning mapping is built through years of training. If one HMI panel shows “Running” as red (because red symbolizes good fortune in Chinese culture), a foreign operator may misdiagnose it as a fault in an emergency. IEC 60073 eliminates this cultural-variation safety risk through global standardization.

TN Lab — Good color standards let people react correctly without thinking.