UNDERGROUND CONDUITS 062288 - UG-1 - Design and Construction Guidelines

Oct 12, 2026

Upload by Rowan

Underground Conduits 062288 (UG-1) provides requirements for steel and plastic conduits used in electric underground installations, with or without concrete encasement. It defines elbows and factory elbows, then specifies applications for residential, light commercial/industrial/URD feeder circuits, and conditions that may require concrete encasement for severe “dig-ins” and hazards. The document also references related PG&E design procedures, installation practices, conduit material substitutions, conduit separation, spare conduit planning, and fitting/chamfering and pulling-tape requirements to protect cable jackets and ensure cleanliness.

LanguageEnglish

CategoryPaper Templates

FormatPDF

Pages28

Reading Time10 min

AccessFree to download

Purpose and Scope

Definitions

General Information

Applications for Underground Conduit

Design and Related Documents

Material Substitutions and Interchangeability

Installation Practices and Requirements

UG-1: Conduits Greenbook Prepared by: MZGD | | | UNDERGROUND CONDUITS 062288 | | | | --- | --- | --- | --- | --- | | Asset Type: | Electric Distribution | Function: | | Design and Construction | | Issued by: | Lisseth Villareal (LDV2) | | Date: | 07−02−26 | | Rev. \#24: This document becomes active on 09−02−26 For a description of the changes, see Page 28. | | | | | Purpose and Scope This document covers steel and plastic conduit for electric underground installations, with or without concrete encasement. Definitions Elbows: factory bends of any degree. Factory elbows or bends: produced at conduit manufacturers per industry standards. General Information 1. Applications for underground conduit are as follows: A. Residential: All residential conduit installations should be made without concrete encasement. B. Light Commercial, Industrial, and Underground Residential Distribution (URD) Feeder: Installation of circuits of this type, which are three-way or less, should normally be made without concrete encasement. In densely populated urban areas, conduit banks involving more than three primary conduits may require concrete encasement. C. Severe exposure to “dig-ins” and other hazards may require concrete encasement of conduit lines. (1) Conduit separation for concrete encasement of conduit lines using spacers to avoid obstacles is illustrated on Page 20. (2) Conduit separation for concrete encasement of conduit lines terminating into a manhole or vault, is illustrated on Page 21. (3) Concrete encasement conduit configuration is illustrated on Page 22. 2. For the minimum design requirements for trenches and conduits installed in PG&E electric distribution system see Document 038193. Trench requirements previously listed in this document have been moved to Document 038193. 3. For the design requirements of conduits installed specifically on bridges see Utility Procedure TD-2310P-10 . 4. For the application, installation, recommendation and requirements of cable−in−conduit (CIC) see Utility Procedure TD−2312P−01 . 5. In April of 2020, PG&E stopped purchasing rigid Polyvinyl Chloride (PVC) DB-120 for conduits, couplings, fittings, and bends for installation in its electric distribution system. After April 2020 PG&E purchases rigid single wall or co-extruded cellular core wall PVC Schedule 40 conduits, couplings, fittings and bends as the standard conduit type for open trench installations. 6. Rigid single wall or co−extruded cellular core wall PVC Schedule 40 conduits, couplings, fittings, and bends are interchangeable with rigid PVC DB-120 conduits, couplings, fittings, and bends, respectively. This interchangeability is possible because DB-120 and rigid PVC Schedule 40 materials have the same outside diameters. Refer to Note 9 on Page 2 for chamfering requirements. Rev. \#24: 07−02−26 062288 Page 1 of 28 UG-1: Conduits Greenbook Underground Conduits General Information (continued) 7. When conduit, including service conduit, is to be installed for PG&E by others, the conduits must meet the requirements listed in this document. The conduits listed below are also acceptable alternatives to the required Rigid single wall or co−extruded cellular core wall PVC Schedule 40. For conduit installation under piers, hanging on bridges, or highly corrosive environment check with local authority jurisdiction since some cities and countries may have preference on which of the approved conduits (C or D) to use. A. Single wall and co−extruded cellular core wall PVC Schedule 80, UL 651 approved conduit that is so marked. B. Hot-dip galvanized rigid steel conduit conforming to American National Standards Institute (ANSI) Specification C80.1 . C. PVC coated steel conduit and fittings conforming to UL 6 and ANSI Specification C80.1 . Conduit and Fittings must be threaded. (1) Nominal urethane coating on interior and threads must be 2 mil. (2) Minimum PVC coating bonded to exterior

FAQs

What types of underground conduits does this document cover?

It covers steel and plastic conduit for electric underground installations, with or without concrete encasement.

When is concrete encasement normally required?

Residential installations are typically made without concrete encasement, while severe exposure to “dig-ins” and other hazards may require concrete encasement.

What installation requirements help protect cables during conduit joining?

Installers must use proper fittings, including 45° chamfering of the inside edge when joining conduits of different wall thicknesses to reduce risk of damaging the cable jacket.

Oct 12, 2026

Upload by Rowan