A locking system for a disconnect switch mounted to a utility pole. The locking system includes an attachment assembly mounted to the disconnect switch. The attachment assembly has an attachment body with a groove, and a locking arm disposed within the groove and pivotable between an open configuration and a locked configuration. A trigger mechanism extends through the locking arm and selectively secures the locking arm in the locked configuration. The locking system also has a lock assembly mounted to the attachment assembly, which has a lock body defining a central aperture for receiving a key therein. The lock assembly has a rotatable cam disposed at an end of the central aperture. The cam engages the key upon being rotated thereby. When it rotates, the cam engages the trigger mechanism to selectively secure the locking arm in the locked configuration.