California Code of Regulations
Title 8 - Industrial Relations
Division 1 - Department of Industrial Relations
Chapter 4 - Division of Industrial Safety
Subchapter 5 - Electrical Safety Orders
Group 2 - High-Voltage Electrical Safety Orders
Article 26 - Metal-Enclosed Power Switchgear and Industrial Control Assemblies
Section 2863 - Accessibility of Energized Parts

(a) Doors or removable panels which could provide non-qualified persons access to high-voltage energized parts shall be locked or secured by other approved means. When high-voltage metal-enclosed switchgear or control assemblies are accessible only to qualified persons, bolted-on or hinged and bolted cover plates shall be permitted to be used.

(b) Low-voltage control equipment, relays, motors, and the like (except instrument or control transformers which are connected to the high voltage) shall not be installed in compartments with exposed high-voltage energized parts or high-voltage wiring unless the access door or cover is interlocked with the high-voltage switch or disconnecting means to prevent the door or cover from being opened or removed unless the switch or disconnecting means is in the open position.

(c) Switchboards with exposed live parts. Switchboards that have any exposed live parts shall be located in permanently dry locations and shall be accessible only to qualified persons.

(d) Panelboard enclosures. Panelboards shall be mounted in cabinets, cutout boxes, or enclosures designed for the purpose and shall be dead front. However, panelboards other than the dead front externally-operable type are permitted where accessible only to qualified persons.

(e) Knife switches mounted in switchboards or panelboards. Exposed blades of knife switches mounted in switchboards or panelboards shall be dead when open.