Schneider Electric's Square D brand safety switch is designed to be rugged and reliable, providing exceptional performance in the harshest conditions. The safety switches are designed for commercial, institutional, industrial and manufacturing facilities. F Series 60A Fuse Linked Safety Switch Electrical Interlocks are available in kits for field installation. Each kit includes instructions for proper field installation. A swing arm is actuated by the switch mechanism, breaking the control circuit before the main switch blades break. Switches with built-in electrical interlocks are UL Listed. For factory-installed electrical interlocks, add the suffix EI (for one contact) or EI2 (for two contacts) to the catalog number. These electrical interlock kits are for safety switches with a UL Listed certification and a switch function of SPDT.