Switches: Markings, Types, and Safety Considerations

Posted on 7/15/19 7:57 AM From being used on a vacuum cleaner to being used on a life-support machine, the purpose of a switch is to open and close a circuit. A switch is used when incoming power in an electrical product design needs to be controlled. Opening a circuit (turning a device OFF) is achieved by breaking the connection. This interrupts the current flow. Closing the circuit (turning a device ON) allows the current to flow again.On/Off MarkingsA common style of a switch is a rocker design, which includes on/off markings. To meet the standard IEC 60417, the symbol for ON is “I” (a straight line) and the symbol for OFF is “O” (a circle). It is important to check the appropriate equipment standard for instructions regarding the position of “on” as some may require the “I” to be installed in a vertical position.These on/off markings can be found on the end of the actuator or on the face of it. The actuator is the mechanical component used to manually turn a circuit on and off. “Fr...