Underground Conduit and Substructures Specification No. 104 - (Revised 11/04/2021) - Underground circuit specifications and construction standards

Oct 29, 2026

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Underground Conduit and Substructures Specification No. 104 (Revised 11/04/2021) defines construction requirements for underground substructures and conduit systems used by the City of Los Angeles Department of Water and Power. It covers underground circuits up to and including 34.5 kV, including notice and inspection timing, inspection arrangements for special and emergency cases, and how conduits must follow construction drawings. The specification details rules for conduit encasement in concrete by voltage class and addresses methane gas area additional drawing requirements, PVC conduit types, encasement and direct-burial requirements, and sample submission for testing.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages49

Reading Time2 h 3 min

AccessFree to download

SECTION “A” General Provisions

Trench excavation (Section “B”)

Substructures (Section “C”)

Substructure vent installation (Section “D”)

Mainline and service conduit (Section “E”)

Street light conduit (Section “F”)

Substructure backfill (Section “G”)

Conduit trench backfill (Section “H”)

Survey requirements (Section “I”)

Contractor’s responsibilities (Section “J”)

APPENDIX-I Conduit Installation

APPENDIX-II Reference Tables

CITY OF LOS ANGELES DEPARTMENT OF WATER AND POWER POWER DISTRIBUTION DIVISION COMMON SERVICE AND CONSTRUCTIONSTANDARDS UNDERGROUND CONDUIT AND SUBSTRUCTURES SPECIFICATION NO. 104 (REVISED 11/04/2021) CITY OF LOS ANGELES DEPARTMENT OF WATER AND POWER POWER DISTRIBUTION DIVISION UNDERGROUND CONDUIT AND SUBSTRUCTURES SPECIFICATIONS No . 104 (Revised 11/04/2021) CONTENTS SECTION “A”.................................. GENERAL PROVISIONS 2 SECTION “B”….............................. TRENCH EXCAVATION 8 SECTION “C”.................................. SUBSTRUCTURES 11 SECTION “D”.................................. SUBSTRUCTURE VENT INSTALLATION 17 SECTION “E”….............................. MAINLINE AND SERVICE CONDUIT 19 SECTION “F”….............................. STREET LIGHT CONDUIT 25 SECTION “G”................................. SUBSTRUCTURE BACKFILL 26 (VLTS., M.H.’S AND H.H.’S) SECTION “H”................................. CONDUIT TRENCH BACKFILL 29 SECTION “I”................................... SURVEY REQUIREMENTS 32 SECTION “J”................................... CONTRACTOR’S RESPONSIBILITIES 33 APPENDIX-I................................... CONDUIT INSTALLATION 35 APPENDIX-II…………………….. REFERENCE TABLES 46 A. GENERAL PROVISIONS 1(a) . These underground substructure and conduit specifications cover underground circuits rated up to and including 34.5 kV . For underground circuits rated at higher voltages, please contact the Underground Transmission Engineering Group for a project-specific design recommendation. 1(b) . All underground substructures and conduits, in which the Department of Water and Power (Department) installs and maintains cables, and any other associated distribution system components shall be constructed in accordance with: a. For installation on private property: The Department's Electric Service Requirements (ESR) and the Los Angeles Department of Building and Safety (LADBS) requirements, latest editions, where applicable. b. For installation on public property: Chapter VI, Article 2, Section 62.00-62.05 of the Los Angeles Municipal Code and the Standard Specifications for Public Works Construction (SSPWC), latest edition adopted by the Brown Book . All construction shall also comply with the Department's Construction Standards, the Department's Standard Drawing H- 168, latest revision, where applicable, and all the requirements specified herein. 1(c). All underground substructures and conduits placed in known methane gas areas (as identified by the Department of Building and Safety or the Developer), shall also satisfy the requirements of the Department’s Standard Drawing(s) H-242 and 1-802.2, latest revisions. 2(a) . On-site inspection: The Department shall be notified at least two (2) full business days prior to the start of construction. On-site inspections performed by the Department Representative will be made between the hours of 10:00 am and 2:00 pm Monday through Friday. 2(b) . Special inspection: Special inspection, outside the normal business days and/or hours may be arranged by notifying the Department at least five (5) full business days in advance of the date the inspection will be required. The Contractor shall pay any premium time charges that may be incurred by the Department representative. The premium time paid may include travel time 2 (c) . Emergency inspection: Only in case of an emergency, the contractor may request special inspection, if available, without advance notification. The contractor will be required to sign a written agreement obligating them to pay for any premium time charges incurred as a result of the requested special inspection. Final acceptance of the project may be delayed if the Department does not receive reimbursement for the premium charged. 2(d) . Inspection offices: Contact the Department atthe telephone number noted on the construction drawing(s) or marked plot plan(s) . 3(a) . All conduits shall be a

FAQs

What voltage range does Specification No. 104 cover for underground circuits?

It covers underground circuits rated up to and including 34.5 kV. For higher-voltage underground circuits, the specification directs the requester to contact the Underground Transmission Engineering Group for a project-specific design recommendation.

How much advance notice is required for on-site inspection before construction starts?

The Department must be notified at least two (2) full business days before the start of construction. Department representative inspections are performed between 10:00 am and 2:00 pm, Monday through Friday.

When must conduits be encased in concrete?

Conduits housing at least one (1) cable rated 600 volts or higher must be encased in concrete. Conduits carrying cables intended for loads less than 600 volts are not to be encased in concrete unless requested by the Department representative or as shown on the construction drawings.

Oct 29, 2026

Upload by Fahsai