Live parts of electric equipment operating at 50 volts or more must be guarded against accidental contact. Guarding of live parts may be accomplished by:
- location in a room, vault, or similar enclosure accessible only to qualified persons;
- use of permanent, substantial partitions or screens to exclude unqualified persons;
- location on a suitable balcony, gallery, or platform elevated and arranged to exclude unqualified persons; or
- elevation of 8 feet (2.44 meters) or more above the floor.
Entrances to rooms and other guarded locations containing exposed live parts must be marked with conspicuous warning signs forbidding unqualified persons to enter.
Indoor electric wiring more than 600 volts and that is open to unqualified
persons must be made with metal-enclosed equipment or enclosed in a vault or
area controlled by a lock. In addition, equipment must be marked with
appropriate caution signs.