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Subchapter 5. Electrical Safety Orders
Group 2. High-Voltage Electrical Safety Orders
ARTICLE 20. INTERRUPTING AND ISOLATING DEVICES

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§2833.1. Knife Switches.


(a) Single-throw knife switches. Single-throw knife switches shall be so placed that gravity will not tend to close them. Single-throw knife switches approved for use in the inverted position shall be provided with a locking device that will ensure that the blades remain in the open position when so set.

(b) Double-throw knife switches.

Double-throw knife switches shall be mounted so that the throw will be either vertical or horizontal. However, if the throw is vertical, a locking device shall be provided to ensure that the blades remain in the open position when so set.

(c) Connection of switches.

 (1) Single-throw knife switches and switches with butt contacts shall be connected so that the blades are deenergized when the switch is in the open position. 


 (2) Single-throw knife switches, molded-case switches, switches with butt contacts, and circuit breakers used as switches shall be connected so that the terminals supplying the load are deenergized when the switch is in the open position. 


 (3) Blades and terminals supplying the load of a switch may be energized when the switch is in the open position where the switch is connected to circuits or equipment inherently capable of providing a backfeed source of power. For such installations, a permanent sign shall be installed on the switch enclosure or immediately adjacent to open switches that reads: "WARNING - LOAD SIDE TERMINALS MAY BE ENERGIZED BY BACKFEED." 


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    Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.  


 HISTORY 
   
1. New section filed 4-1-2009; operative 4-1-2009. Submitted to OAL for
printing only pursuant to Labor Code section 142.3 (Register 2009, No.
14).

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