Safety Interlock Switches are locking devices which can be used to monitor the position of a machine guard door and turn off the power supply when the safety barrier is released. They can also be used to keep a guard securely locked when machinery is running. This helps to prevent personnel from accessing a hazardous area where machinery may be in motion and minimises risk of injury or equipment damage. Interlock switches are often used for industrial applications with sliding, hinged, and lift-off safety guards.