The LMI-B1 Mechanical Interlock enhances electrical safety by preventing two main circuits from operating simultaneously, effectively safeguarding against potential overload and fire risks. This essential accessory is specifically designed for NB1-63, NB1-63H, and NB1-63DC circuit breakers to ensure reliable manual switching of dual power supplies. It's a versatile solution ideal for ensuring secure and compliant power management in diverse environments, including residential homes, commercial establishments, hotels, shopping malls, and other facilities requiring controlled power source management.