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Subchapter 5. Electrical Safety Orders
Group 2. High-Voltage Electrical Safety Orders
Article 27. Transformers (Formerly Article 76)
§2875. Requirements Applicable to Specific Types and Locations of Transformers.
(a) Indoor Installations. Oil-insulated transformers shall not be installed indoors except in a vault constructed in accordance with Sections 2805 and 2806, or a separate building meeting the requirements of Section 2807.
(b) High Fire Point Liquid-Insulated Transformers. Transformers insulated with a listed, less flammable liquid (high fire point) shall be permitted to be
installed without a vault in a non-combustible occupancy area of non-combustible buildings, provided there is a liquid confinement area and the liquid is listed as having a fire point of not less than 300 degrees C. Such transformers installed indoors and rated over 35,000 volts shall be installed in a vault.
(c) Dry-type, high fire point liquid-insulated, and askarel-insulated transformers installed indoors and rated over 35kV shall be in a vault.
(d) Protection from Flooding. Transformers and associated equipment subject to flooding shall be submersible.
(e) Protection Against Toxic Gases. Precautions shall be taken to prevent transformers from venting toxic or explosive gases into an inadequately ventilated space.
(f) Outdoor Installations. Transformers shall be permitted to be installed in outdoor enclosures meeting the requirements of Section 2812.1 or on roofs in accordance with Section 2808. Transformers installed on poles or structures shall conform to Rule 58.3, General Order No. 95, 1981 Edition, Rules for Overhead Electric Line Construction of the California Public Utilities
Commission, which is hereby incorporated by reference. Transformers installed underground shall conform to Rule 34.2C, General Order No. 128, 1974 Edition, Rules for Construction of Underground Electric Supply and Communications Systems of the California Public Utilities Commission which is hereby incorporated by reference
<General Materials (GM) - References, Annotations, or Tables>
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
1. Amendment filed 10-29-80; effective thirtieth day thereafter (Register 80,
2. Amendment of subsection (b) filed 3-2-83; effective thirtieth day
thereafter (Register 83, No. 10).
3. Editorial correction filed 11-2-83 (Register 83, No. 45).
4. Amendment filed 12-10-87; operative 1-9-88 (Register 88, No. 1).
5. Amendment of section and Note 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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