Draft Details
- Underground systems (New Edition)
- DRAFT STANDARD
- Legal Notice for Draft Standards
- Preface
- + 1 Scope
- 1.1 Scope
- 1.2 Prior editions
- 1.3 Applications
- 1.4 Exclusion
- 1.5 Common standards
- 1.6 Types of construction
- 1.7 Where practicable Clause deleted
- 1.7 Shall, should, may, notes
- 2 Reference publications
- 3 Definitions
- + 4 General requirements
- 4.1 General and Maintenance
- 4.1.1 General
- 4.1.2 Maintenance
- + 4.2 Location of underground systems
- 4.2.1 General
- 4.2.2 Standard location
- + 4.2.3 Subsurface chambers
- 4.2.3.1 Access
- 4.2.3.2 Location
- 4.3 Steam pipelines
- 4.4 Crossings
- + 4.5 Excavating
- + 4.5.1 General
- 4.5.1.1 General
- 4.5.1.2 Right-of-way
- 4.5.1.3 Crossing under railway
- + 4.5.2 Backfilling
- 4.5.2.1 General
- 4.5.2.2 Vehicular traffic
- 4.5.2.3 Damage to underground plant
- 4.5.2.4 Distortion of ducts
- 4.5.2.5 Subsidence, erosion
- 4.5.2.6 Crossing heavy railway
- 4.5.2.7 Damage during installation, operation
- 4.5.2.8 Native material damage to underground p...
- 4.5.3 Surface grade
- 4.5.4 Unstable soils
- + 4.6 Risers
- 4.6.1 Separation between risers of communicatio...
- 4.6.2 Mechanical protection of supply cables
- 4.6.3 Mechanical protection of supply grounding...
- 4.6.4 Mechanical protection of communication ca...
- 4.6.5 Non-conducting covering for supply ground...
- 4.6.6 Grounding of riser pipes and guards
- + 4.7 Installation, splicing, and termination of ...
- 4.7.1 General
- 4.7.2 Installation
- 4.7.3 Protection against moisture
- 4.7.4 Grounding and bonding of cable shields/sh...
- 4.8 Distributed generation
- 4.9 Corrosion control
- 4.10 Seismic withstand
- + 5 Depth of burial
- + 5.1 Depth of burial — Direct-buried systems
- 5.1.1 General
- 5.1.2 Communication cables
- 5.1.3 Supply cables
- 5.1.4 Cable crossings
- 5.1.5 Reduced burial depth
- + 5.2 Depth of burial — Duct and subsurface chamb...
- 5.2.1 General
- 5.2.2 Reduced depth of burial
- 5.3 Depth below grade — Grounding conductors
- + 6 Separations
- + 6.1 Separations — Direct-buried systems
- 6.1.1 Separation from underground systems
- + 6.1.2 Separation from structures
- 6.1.2.1 Separation from underground portion of ...
- 6.1.2.2 Separation from another party
- + 6.1.3 Separation from swimming pools
- 6.1.3.1 Horizontal separation from swimming poo...
- 6.1.3.2 Separation of swimming pools and >28kV...
- 6.1.4 Separation from propane tanks
- 6.1.5 Separation from pipelines
- 6.1.6 Crossing pipelines
- 6.1.7 Separation between cables in separate tre...
- + 6.1.8 Fixed separation between cables in a comm...
- 6.1.8.1 Communication cables and supply cables ...
- 6.1.8.2 Communication cables and supply cables ...
- 6.1.8.3 Supply cables of the same three-phase c...
- 6.1.8.4 Supply cables of different voltages and...
- 6.1.8.5 Other supply cables
- + 6.1.9 Random separation between supply and comm...
- 6.1.9.1 Supply cables 7501000 V or less
- 6.1.9.2 Supply cables greater than 7501000 V
- 6.1.9.3 Grounded bare neutral (unjacketed) supp...
- 6.1.9.4 Jacketed supply cables greater than 750...
- 6.1.9.5 Crossing of facilities not installed un...
- + 6.1.10 Cable crossings
- 6.1.10.1 General
- 6.1.10.2 Supply and communication cables
- + 6.1.11 Common trench (supply, communication, an...
- 6.1.12 – Separation from Soil Cell and Direct B...
- + 6.2 Separations — Duct systems
- + 6.2.1 General
- 6.2.1.1 Parallel underground system ducts
- 6.2.1.2 Crossing underground facility ducts
- + 6.2.2 Separation from pipelines
- 6.2.2.1 General separations from pipelines
- 6.2.2.2 Crossing an underground pipeline
- + 6.2.3 Separation from swimming pools
- 6.2.3.1 Horizontal separation from swimming poo...
- 6.2.3.2 Separation of swimming pools and >28kV...
- 6.2.4 Separations from propane tanks
- 6.2.5 Iron or steel pipe used as ducts
- 6.2.6 Separation between concrete-encased suppl...
- + 6.2.7 Separation between cables
- 6.2.7.1 Cables of supply and communication syst...
- 6.2.7.2 Cables in a common duct bank
- 6.2.7.3 Cables in the same subsurface chamber
- 6.2.8 – Separation from Soil Cell and Duct Syst...
- 6.3 Horizontal separation between grounding ele...
- 6.4 Separation between grounding conductors and...
- + 6.5 Separation from natural gas or propane equi...
- 6.5.1 Natural gas separation
- 6.5.2 Propane gas separation
- 6.5.3 Propane tanks
- + 7 Construction of direct-buried systems
- + 7.1 Installation of cables
- 7.1.1 General
- 7.1.2 Plowing of cables
- 7.2 Cable trench
- + 7.3 Mechanical protection
- 7.3.1 General
- + 7.3.2 Installation of mechanical protection
- 7.3.2.1 General
- 7.3.2.2 Examples of mechanical cable protection...
- 7.3.2.3 Mechanical protection for special appli...
- 7.4 Building entrances
- 7.5 Settling
- + 8 Construction of a duct or duct banks
- 8.1 General
- 8.2 Materials
- 8.3 Loadings
- + 8.4 Ducts in bridge structures
- 8.4.1 Ducts passing through, attached to bridge...
- 8.4.2 Ducts passing through bridge abutment
- 8.5 Ducts encased in concrete
- + 8.6 Ducts enclosed in steel pipe
- 8.6.1 Ducts enclosed in steel pipe
- 8.6.2 Prevention of overheating
- + 8.7 Ducts requiring no additional protection
- 8.7.1 General
- 8.7.2 Multiple ducts in open trench
- 8.8 Ducts with additional protection
- 8.9 Grading of ducts
- 8.10 Settling
- 8.11 Cleaning and testing of ducts
- 8.12 Cable pulling tension (duct structure)
- + 8.13 Terminating ducts
- 8.13.1 General
- 8.13.2 Entrances to buildings and other structu...
- + 9 Construction of vaults, subsurface chambers, ...
- 9.1 Wheel load capability of underground civil ...
- 9.2 Backfilling
- + 9.3 Dimensions
- 9.3.1 Dimensions
- 9.3.2 Exceptions to dimensions
- 9.4 Duct entrances into vaults, subsurface cham...
- 9.5 Drainage
- 9.6 Openings in subsurface chambers
- + 9.7 Vault doors, subsurface box covers, and sub...
- 9.7.1 Covers
- 9.7.2 Doors, covers
- + 9.8 Hardware
- 9.8.1 Provisions for pulling cables
- 9.8.2 Walls of vaults
- + 9.9 Ventilation
- 9.9.1 Cables in subsurface chambers
- 9.9.2 Transformers in subsurface chambers
- 9.9.3 Other equipment in subsurface chambers, s...
- 9.9.3 4 Other ventilation requirements
- 9.10 Safe access, working, and rescue provision...
- 9.11 Accessibility of cables
- + 9.12 Guarding of live parts in subsurface chamb...
- 9.12.1 Cable splices or terminals
- 9.12.2 Electrical equipment
- 9.13 Seismic withstand
- + 10 Above-ground equipment
- 10.1 Location of above-ground facilities
- 10.2 Working space
- + 10.3 Supply equipment
- 10.3.1 Supply equipment access
- 10.3.2 Above-ground duct attached to supply enc...
- 10.3.3 , Ventilation
- 10.4 Joint-use equipment
- 10.5 Mechanical protection of pad-mounted equip...
- 10.6 Seismic withstand
- 10.7 Flood protection of pad-mounted equipment
- + 11 Installations on railway rights-of-way
- 11.1 Loading
- + 11.2 Crossings
- 11.2.1 Crossings under heavy rail tracks
- 11.2.2 Crossings under light rail tracks
- + 11.3 Casing pipe material
- 11.3.1 Steel casing pipe
- 11.3.2 Non-steel casing pipes
- 11.3.3 Precast concrete, corrugated metallic pi...
- 11.4 Installation of casing pipes
- + 11.5 Longitudinal cable installations on railwa...
- 11.5.1 Ducts laid longitudinally on railway rig...
- 11.5.2 Direct-buried, longitudinal cable instal...
- + 11.6 Depth below base of rail
- 11.6.1 Depth below base of heavy rail
- 11.6.2 Depth below base of light rail
- + 11.7 Horizontal distance from railways
- 11.7.1 Horizontal distance from heavy rails
- 11.7.2 Horizontal distance from light rails
- + 12 Submarine cable installations
- 12.1 Location of submarine cables
- 12.2 Clearance from structures
- 13 Transmission cable installations
- + 14 Electrical requirements
- 14.1 Induced voltages and current
- 14.2 Overvoltage protection
- 14.3 Inductive coordination
- 14.4 Overcurrent protection — Supply cables gre...
- + 14.5 Communication cables
- 14.5.1 Metallic shields, sheaths
- 14.5.2 Fault condition
- + 14.6 Voltage limitations on communication cable...
- 14.6.1 General
- 14.6.2 Metallic sheathed cable
- 14.6.3 Supply line requirements
- + 14.7 Electrical protection — Direct-buried syst...
- 14.7.1 Communication and supply cables in a com...
- 14.7.2 Communication and supply cables installe...
- + 15 Grounding and bonding
- 15.1 General
- 15.2 Current-carrying capacity
- 15.3 Supply cables operating at a voltage great...
- + 15.4 Supply equipment (pad-mounted and in chamb...
- 15.4.1 Pad-mounted supply equipment
- 15.4.2 Equipment in chambers
- + 15.5 Supply grounding electrodes and connection...
- 15.5.1 General
- 15.5.2 Frost level
- 15.5.3 Rod-type grounding electrodes
- + 15.6 Grounding conductors
- 15.6.1 Conductor composition
- + 15.6.2 Gradient control
- 15.6.2.1 Step and touch potentials
- 15.6.2.2 Barriers
- 15.6.2.3 Rebar
- 15.6.2.4 Metallic objects and supply equipment
- 15.7 Bonding of communication and supply equipm...
- + 16 Records and identification of underground pl...
- 16.1 Records
- + 16.2 Marking of plant locations
- 16.2.1 General
- 16.2.2 Marking for reduced depth of burial of s...
- 16.3 Identification of direct-buried cable duct...
- 16.4 Temporary identification
- + 16.5 Identification of cables and apparatus
- 16.5.1 Identification of apparatus, devices, an...
- 16.5.2 Identification of multiple cables
- 16.6 Identification of cables in subsurface cha...
- + 16.7 Identification of jacketed cables
- 16.7.1 General
- 16.7.2 Exemptions
- 16.8 Identification of interconnected apparatus...
- 16.9 Identification of switching devices
- Table 1
- Table 2
- Table 3
- Table 4
- Table 5
- Table 6
- Table 7
- Table 8
- Table 9
- Figure 1
- + Annex A (informative)
- + A.1 Scope
- A.1.1 Scope
- A.1.2 Prior version
- + A.4 General requirements
- A.4.1.1 General
- Table A.4.1.1
- + A.4.2 Location of underground systems
- A.4.2.1 General
- Table A.4.2.1
- A.4.2.2 Standard location
- + A.4.5 Excavating
- A.4.5.4 Unstable soils
- + A.4.7 Installation, splicing, and termination o...
- A.4.7.1 General
- A.4.7.4 Grounding and bonding of cable shields/...
- + A.6 Separations
- + A.6.1 Separations — Direct-buried systems
- + A.6.1.1 General
- + A.6.1.8 Fixed separation between cables in a co...
- A.6.1.8.2 Communication cables and supply cable...
- + A.6.1.9 Random separation between supply and co...
- A.6.1.9.1 Supply cables 7501000 V or less
- A.6.1.12 Separation from Soil Cell and Direct B...
- + Figure A.6.1.12: Separation of Supply / Commun...
- A.6.2.8 Separation from Soil Cell and Duct Syst...
- A.6.3 Horizontal separation between grounding e...
- + A.7 Construction of direct-buried systems
- + A.7.1 Installation of cables
- A.7.1.1 General
- + A.8 Construction of a duct or duct banks
- A.8.10 Settling
- A.8.12 Cable pulling tension (duct structure)
- + A.9 Construction of vaults, subsurface chambers...
- A.9.5 Drainage
- A.9.7 Vault doors, subsurface box covers, and s...
- A.9.9.2
- A.9.9.3 Other equipment in subsurface chambers,...
- A.10.3.3 Ventilation
- A.9.13 Seismic withstand
- + A.10 Above-ground equipment
- A.10.6 Seismic withstand
- A.10.7 Flood protection of pad-mounted equipmen...
- + A.11 Installation on railway rights-of-way
- A.11.1 Loading
- A.11.6 Depth below base of rail
- A.11.7 Horizontal distance from railways
- + A.12 Submarine cable installations
- A.12.1 Definitions
- A.12.2 General
- Table A.1
- + A.13 Transmission cable installations
- A.13.1 Parallel separations
- A.13.2 Crossing separations
- A.13.3 Thermal considerations
- + A.13.4 Recommended minimum separations
- A.13.4.1
- A.13.4.2
- + A.13.5 Bibliography
- A.13.5.1 General
- A.13.5.2 High-voltage cable installation
- A.13.5.3 High-voltage cable specifications
- + A.14 Electrical requirements
- A.14.2 Overvoltage protection
- + A.15 Grounding and bonding
- A.15.1 General
- + A.16 Records and identification of underground ...
- A.16.3 Identification of direct-buried cable du...
- + A.16.5 Identification of cables and apparatus
- A.16.5.1 Identification of apparatus, devices, ...
- Figure A.1
- Figure A.2
- Figure A.3
- Figure A.4
- Figure A.5
- Figure A.6
- Figure A.7
- Figure A.8
- Figure A.9
- + Annex B (informative)
- Figure B.1
- Figure B.2
- Figure B.3
- + Annex C (informative)
- C.1 General
- + C.2 Separations
- C.2.1 Separation from other underground systems...
- C.2.2 Horizontal separation from pipelines
- C.2.3 Crossing over underground pipelines
- C.2.4 Horizontal separation from propane tanks
- + C.3 Construction of surface channel systems
- C.3.1 General
- C.3.2 Materials
- C.3.3 Mechanical strength
- C.3.4 Covers
- C.4 Surface trench
- + C.5 Location of supply and communication cables...
- C.5.1 Separation of voltages
- C.5.2 Separate systems
- C.5.3 Same surface channel system
- C.6 Guarding of live parts
- Figure C.1
- + Annex D (informative)
- Figure D.1
- Figure D.2
- Figure D.3
- Figure D.4
- Figure D.5
- + Annex E (informative)
- E.1 Crossings, trenchless technology
- E.2 HDD under watercourses, roads
- E.3 HDD benefits
- + Annex F (informative)
- F.1 Microtrenching
- + Annex G (informative)
- Figure G.1 – Transformer installed outside, cl...
- Figure G.2 – Bonding of rebar
- Figure G.3 – Transformer installed in an alcov...
- Figure G.4 – Grounding System – Top View
- Figure G.5 – Grounding System – Side View
- + Annex J (informative)
- J.1 Introduction
- Table J.2
- Table J.3
- J.2 Mean Annual Maximum Snow Depth
- J.3 Temperature
1.1 Scope
This Standard applies to the lines and equipment associated with underground electric supply and communication systems located
a) entirely outside of buildings;
b) outside of indoor supply stations and fenced outdoor supply stations;
c) and buildings, and also where the installations or equipment are inside buildings or sections of buildings where they are employed by a utility of
ai) an electric system;
bii) a communication system; or
ciii) a community antenna distribution system
in the exercise of its function as a utility.
This Standard, which forms part of the Canadian Electrical Code, Part III, covers the requirements for construction of underground systems and includes electric supply and communication circuits that are installed alone, in joint use, or in proximity to each other or other facilities.
Note: See CSA C22.3 No. 61936-1 for installations within fenced or indoor supply stations.
1.2 Prior editions
Existing installations meeting the requirements of prior editions of this Standard need not be modified to comply with this edition of the Standard, except as might be required for safety reasons by the authority having jurisdiction.
1.3 Applications
The requirements of this Standard do not constitute complete construction specifications but stipulate the minimum design requirements with regard to
a) safety to persons;
b) continuity of service; and
c) protection of property.
1.4 Exclusion
The selection, design, and installation of supply transmission cables (≥ 69 kV) are not addressed in this Standard.
1.5 Common standards
Conditions not covered by this Standard are governed by equivalent Standards in common use or by the authority having jurisdiction.
1.6 Types of construction
In some cases, requirements are written for specific types of construction. This does not preclude the use of other types of construction arising out of continuing advancements in the field, provided that engineering representatives can demonstrate the safety and suitability of these alternatives.
1.7 Where practicable Clause deleted
The use of terms such as “where practical” is not intended to provide an opportunity for not meeting the minimum requirements of this Standard. When an alternative is not specified, the engineering solution that most closely approximates the preferred method is to be used.
1.7 Shall, should, may, notes
In this Standard, “shall” is used to express a requirement, i.e., a provision that the user is obliged to satisfy in order to comply with the Standard; “should” is used to express a recommendation or that which is advised but not required; and “may” is used to express an option or that which is permissible within the limits of the Standard.
Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate from the text explanatory or informative material.
Notes to tables and figures are considered part of the table or figure and may be written as requirements.
Annexes are designated normative (mandatory) or informative (non-mandatory) to define their application.
You may comment on any section of this document by clicking the “Submit Comment” link at the bottom of the relevant section.