|This information is provided free of charge by the Department of Industrial Relations from its web site at www.dir.ca.gov. These regulations are for the convenience of the user and no representation or warranty is made that the information is current or accurate. See full disclaimer at http://www.dir.ca.gov/od_pub/disclaimer.html.|
| Return to index
Means shall be provided for interrupting the load and magnetizing currents and for isolation of each transformer, transformer bank, or transformer installation. Switches used for these purposes shall be capable of carrying the maximum load current at the point of installation and shall meet the requirements of Article 20.
(a) Load Current. Means shall be installed on either the supply or load side to interrupt the maximum load current of each transformer, transformer bank, or transformer installation that will be switched as a unit. If the load break means is installed on the load side, it may consist of a main transformer switching device or a combination of two or more switching devices carrying the entire transformer load.
(b) Magnetizing Current. Means shall be installed to interrupt the magnetizing current of each voltage regulator, transformer, transformer bank, or transformer installation that will be switched as a unit. Interrupter switches that are not rated to interrupt the maximum load current at the point of installation shall be mechanically interlocked with the load break device required by subsection (a) above.
(c) Isolation. Means shall be installed to isolate from all sources of potential each transformer, transformer bank, or transformer installation that will be removed from service as a unit. Isolating or disconnecting switches that are not rated to interrupt the maximum load current at the point of installation shall be mechanically interlocked with the load break device required by subsection (a) above. If not rated to interrupt magnetizing current,they shall also be interlocked with any separate magnetizing current interrupting switch(es) that may be provided.
EXCEPTION: Where such interrupter switches or disconnects are mounted out of doors, a permanent warning sign meeting the requirements of Section 2835 (h) shall be permitted to be provided in lieu of interlocking.
(d) Additional Requirements for Voltage Regulators. Proper switching sequence for regulators shall be assured by use of one of the following:
(1) Mechanically sequenced regulator bypass switch(es).
(2) Mechanical interlocks.
(3) Switching procedure prominently displayed at the switching location.
(Title 24, Part 3, Section 3-450-51.)
NOTE: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
1. Editorial correction filed 11-2-83 (Register 83, No. 45).
2. Amendment filed 12-10-87; operative 1-9-88 (Register 88, No. 1).
Go Back to Article 27 Table of Contents