Circuit Breaker Locking Device for Schneider MCCB's with Multiple Padlocking Facility. Steel Construction. Color: Black. Number of Locks: 3. Hole Diameter: 8.15mm. Dimensions: W 36.63 mm x L 49.14 mm x D 3.87 mm. ? This device engages in the slot behind the switch toggle, blocking its operation. Adding a padlock prevents unathorised operation and secures the device in place when the breaker is in the OFF position.