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 20 - Interrupting and Isolating Devices
Section 2835 - Disconnecting (Isolating) Switches

(a) General. Disconnecting switches shall be permitted to be single-pole or multiple-pole.

(b) Isolating Means. A suitable air break switching device shall be installed to isolate each oil switch or group of oil switches from all sources of supply unless automatic disconnecting switchgear equipment of the metal-clad draw-out type is used.

EXCEPTION: In highly corrosive or flammable atmospheres, suitable isolating means other than air break shall be used, or the isolating means shall be installed in an enclosure approved for use in such locations of the particular hazard involved.

(c) Accessible to Qualified Persons Only. Disconnecting switches installed in locations where only qualified persons are permitted access shall be installed in suitable enclosures, or shall be elevated above the floor not less than clearances shown in Section 2934.

(d) Accessible to Other Than Qualified Persons. Disconnecting switches installed in any location where other than qualified persons have access shall be installed in suitable enclosures.

The door or cover of the enclosure shall be kept closed, except when opened for operation or inspection. If installed so that the bottom of the enclosure is less than 8 feet above the floor, the door or cover shall be kept locked.

When disconnecting switches are operable from outside the enclosure by a remote control mechanism, the operating handle or lever shall be kept locked when in either the open or closed position.

(e) Operation. Isolating switches shall be provided with suitable means for safe normal operation. This operating means shall be permitted to be an insulated hookstick, an insulated external operating handle, or remote control mechanism. Disconnecting switches shall provide a visible gap in the circuit adequate for the operating voltage.

Provision shall be made to observe the position of the blades of disconnecting switches. If viewing windows are provided, they shall be shatterproof, of adequate size, and suitably located to permit viewing of all contacts. Metal-enclosed switches other than those designed for hookstick operation shall be arranged to be locked in the open position. Multiple switches in the same enclosure shall be equipped with a connection diagram.

(f) Rating. Disconnecting switches shall have current and voltage ratings not less than the full-load current and operating voltage of the circuit. The momentary rating of disconnecting switches shall equal or exceed the asymmetrical short circuit current available at the switch location. The asymmetrical short circuit current shall include contributions from all connected sources of energy, such as other lines, generators, large motors, etc.

(g) Identification. The disconnecting switches shall have a permanent and legible nameplate including the following information: continuous current rating, maximum voltage rating, momentary current rating.

(h) Warning Signs. Unless so interlocked that they cannot be opened under load, disconnecting switches shall be provided with permanent warning signs having letters at least 2 inches high and reading as follows: "Warning--Disconnecting Switch--Do Not Open Under Load." When a group of disconnecting switches is installed in one room or enclosure, a single sign may be sufficient.

(i) Barriers. Suitable barriers shall be installed on both sides of each pole of disconnecting switches mounted indoors.

(Title 24, Part 3, Section 3-710 - 22.)