Push Button Switch Application Scenarios & Circuit Symbol Standards

Standard SB marking rules and typical usage in automation control panels

Push button switches are marked as SB in electrical circuit drawings. Designers label SB1 for start button, SB2 for stop button and SB0 for emergency stop. Different graphic symbols are used for NO, NC and composite buttons. Composite button drawings highlight the break-before-make action sequence for circuit safety.
These switches are widely applied across industrial sectors. Machine tools, water pump control cabinets, conveyor lines, PLC automation boxes and lifting equipment panels all adopt push buttons for manual control. Green buttons are normally for startup while red ones are used for stop and emergency stop, following global electrical color conventions.
Push buttons only handle low-current control loops. The large current of motors is switched by contactors triggered via button signals. This separation protects operators and extends component lifespan. Key lock buttons prevent unauthorized operation for heavy machinery. LED illuminated push buttons display real-time equipment status for operators to identify faults at a glance. Proper symbol recognition helps technicians read wiring diagrams and speed up on-site maintenance.