30 CFR 57.12006 - Distribution boxes.
Distribution boxes shall be provided with a disconnecting device for each branch circuit. Such disconnecting devices shall be equipped or designed in such a manner that it can be determined by visual observation when such a device is open and that the circuit is deenergized, and the distribution box shall be labeled to show which circuit each device controls.
Title 30 published on 2013-07-01
no entries appear in the Federal Register after this date.