Seattle Elect.pdf

STANDARDS FOR

ELECTRIC SERVICE

2023 Edition i

Seattle City Light

Standards for

Electric Service 2023 Edition

Welcome to the 2023 edition of the Seattle City Light Standards for Electric Service. This is an annually produced collection of all standards referenced in the Requirements for Electric Service Connection (RESC) and in Service Construction Letter attachments.

The Standards for Electric Service is designed for use by Engineering & Technology Operations staff as well as customers, developers, and contractors. The standards in this collection apply whenever any public or private construction is performed within City Light Service Territory.

All standards included in this edition are effective as of January 2023.

Mike Haynes, Assistant General Manager ii

Standards for Electric Service 2023 Edition

Published by the Seattle City Light Standards Engineering Organization Seattle, Washington

January 2023

Prepared by Laura Vanderpool Cover photo credit: John Shipek

Printed on 100% recycled content paper

Standards for Electric Service 2023 Edition Table of Contents iii

Preface Significant Additions and Revisions Since Last Publication .................................................................................................. page v Service Construction Letter Attachment Cross-Reference .................................................................................................. page vii

Construction Standards

0130.30 Secondary Service Drops

0214.00 Clearances Between SCL Underground Assets and Non-SCL Structures and Objects

0221.01 Customer Requirements for Trenching in the Right-of-Way

0222.02 Requirements for Primary Conduit and Duct Bank Installation

0222.04 Duct Bank Reinforcement

0222.06 Duct Bank Termination

0223.03 Customer Requirements for Horizontal Directional Drilling (HDD)

0223.33 Cast-in-Place Concrete Vault Collars

0224.01 Customer Requirements for Underground Secondary Service, Looped Radial System

0224.07 Requirements for Secondary Conduit Installation

0224.34 Steel Conduit Risers

0226.06 Installation of Fluidized Thermal Backfill

0230.03 Requirements for Pad-Mounted Termination Enclosure Installations

0231.01 Secondary Handhole Installation and Grounding

0231.03 Cast-in-Place Risers

0257.06 Ceiling Channel for In-Building Vaults

0257.47 Pulling Iron Installation for In-Building Vaults

0461.10 Grounding Electrodes for Handholes and Vaults

0468.90 Exothermic Connection System

0473.50 Looped Radial and Network Service Entrance Cables in Conduit for UG Primary Service

0474.08 Looped Radial and Network Dry Vault Service Entrance Bus Duct for UG Primary Service ... 120

0674.06 In-Building Vault Lighting and Receptacle Requirements, Looped Radial System

0724.50 Customer Requirements, Pad-Mounted Transformers, Looped Radial System

0732.50 Customer Requirements, Below-Grade Transformer Vaults, Looped Radial System

0735.50 Oil Containment Systems

0751.00 Customer Requirements, In-Building Transformer Vaults, Network and LR Systems

0751.49 In-Building Transformer Vault Doors

0751.60 Concurrent Customer Requirements, In-Building Transformer Vaults

0751.77 In-Building Vault Equipment Clearances

1553.03 Meter Base and Socket Configurations

1554.33 Meter Mounting Configurations, Heights, Working Space, and Clearances, Exterior

1554.42 Meter Height, Dedicated Equipment Space, Working Space, and Clearances, Equipment Rooms

1561.05 Underground Residential Service Entrances

1561.07 Customer Requirements for UG Secondary Service Termination Facilities

1561.09 Customer Requirements for UG Secondary Service Termination Handholes in the Public ROW

1611.05 Excavation in the Vicinity of Underground Transmission Lines D2-3 Clearances from Structures and Ground NVH-80 Network Area Requirements for Panel or Cast-in-Place Vaults U2-11.40/NDK-40 Mandreling and Cleaning of Ducts and Conduits U2-14.2 Vault Installation U2-15.1 Installation of Ring-Type Vaults U2-22 Precast Panel Vault Installation, General Non-Network Area

Continued on the next page

Standards for Electric Service 2023 Edition Table of Contents iv

Material Standards

6103.90 Wire, Copper, Bare, Soft-Drawn

6762.25 Ground Rods, Copper-Covered, Sectional

6836.2 Limiter, 600 V, Copper Cable to Bus Bar

6836.3 Limiter, 600 V, Copper Cable to Copper Cable

6836.50 Limiter, 600 V, Aluminum Cable to Bus Bar

6836.6 Limiter, 600 V, Aluminum Cable to Aluminum Cable

7005.05 Tape, Detectable, Underground

7015.05 Schedule 40 PVC Conduit and Fittings

7015.80 Conduit Spacers for PVC and FG Conduit

7050.05 Zinc-Coated Steel Conduit and Fittings

7050.09 Conduit Fitting, Cable Protector

7050.11 Couplings, Set Screw, Rigid Metallic Conduit (RMC) and Intermediate Metallic Conduit (IMC)

7055.09 DB120, PVC Conduit Fittings

7150.00 Fluidized Thermal Backfill

7203.01 Precast Reinforced Concrete Handholes, General Requirements

7203.04 3030 Handhole, Precast, Secondary

7203.08 231 and 233 Handholes, Precast, Secondary and Streetlight, Detailed

7203.10 Type 1 and Type 2 Open Bottom Handhole, Precast, Secondary and Streetlight

7203.12 Handhole, Secondary, Composite Fiberglass, Polymer Concrete

7203.21 Precast Reinforced Concrete Structures, General Requirements

7203.26 444 Enclosures, Precast

7203.31 504 Electric Vault, Primary Service

7203.36 507 Electric Vault, Primary Service

7203.38 575 Electric Vault, Primary Service

7203.41 577 Electric Vault, Primary Service

7203.46 712 Electric Vault, Primary Service

7203.51 814 Electric Vault, Primary Service

7203.66 687 Electric Vault, Primary Service

7203.76 Precast Reinforced Concrete Transformer Pads

7645.30 Pull Tape, Polyester

7645.40 Mandrels, Proofing

7651.25 Customer Requirements for Vault Signage

Standards for Electric Service 2023 Edition

Significant Additions and Revisions Since Last Publication v

NEW STANDARDS

Std No. Title Description

0100.04 Clearance Between 26 kV Overhead

Distribution Conductors and Buildings New standard that clarifies the 14-ft clearance requirement to buildings; content relocated from SCL D2-3 and revised for additional clarity.

0257.47 Pulling Iron Installation for In-Building

Vaults

Content from NCI-62 revised and migrated to new standard number. NCI-62 canceled.

1554.33 Meter Mounting Configurations, Heights, Working Space, and Clearances, Exterior (Outdoor)

Includes some content from 1561.05 as well as from the RESC; all requirements reviewed and revised as appropriate as requested by key stakeholders.

1554.42 Meter Height, Dedicated Equipment

Space, Working Space, and Clearances, Equipment Rooms

New standard to define meter requirements for equipment room installations.

REVISED STANDARDS

Std No. Title

Description D2-3 Clearances from Structures and Ground 14-ft clearance requirement to buildings information relocated from this standard to new standard 0100.04.

U2-15.1 Installation of Ring-Type Vaults Revised sealing and vault depth language as follows:

Added the label “grout seams inside and out” to figures 2 and 3.

Updated labels to reflect current drawing specifications.

Added a statement to Section 2, “See specific material standard to calculate minimum depth.”

0214.00 Clearances Between SCL Underground

Structures and Other Structures

Revised title from “Clearances Between SCL Underground Structures and Other Structures” to “Clearances Between SCL Underground Assets and Non-SCL Structures and Objects”

Changed various section and table titles to reflect new standard title language.

Revised scope language.

Added clearance requirements for SCL wood poles to Section 9, Figure 9a.

Significant Additions and Revisions Since Last Publication vi

REVISED STANDARDS, continued

Std No. Title Description

0224.07 Requirements for Secondary Conduit

Installation

Revised Table 4 to change material for backfill to sub-grade on private property in the Looped Radial system from “native soil” to “clean native soil or Type 17.

Added a note to the encasement requirement in the Looped Radial system stating , “Encasement is required when installing four or more conduits 4 inches or larger between two facilities or when directed by SCL Engineering.”

Added additional conduit requirements, six statements that appear below Table 6b.

Added a second note (note b) to Table 6a regarding straight, Schedule 40 PVC as follows: “When installed with rigid galvanized steel (RGS) bends.”

0231.01 Secondary Handhole Installation and

Grounding

Note underneath Figure 4.3.1 changed to remove the phrase “In Looped Radial areas..”

0461.10 Grounding Electrodes for Handholes and

Vaults

Added the definition for “exothermic waterstop” to the Definitions section and added the requirement to form an exothermic waterstop to the installation requirements in each section.

Added a new section 6.5 titled, “Mixed-Use Vault, Handhole, or Pole/Pedestal Foundation.”

1561.05 Underground Residential Service

Entrances

Relocated meter clearances and height requirements from this standard to the new construction standard SCL 1554.33, “Meter Mounting Configurations, Heights, Working Space, and Clearances, Exterior (Outdoor).”

Sections rearranged and renumbered for better organization to accommodate removal of meter clearance figures and verbiage.

Figures revised to show steel bends below grade, as well as to illustrate a semi-flush meter instead of a recessed meter.

CANCELED STANDARDS

Std No. Title

Description NCI-62 Content revised and migrated into new standard number

0257.47

Service Construction Letter Attachment Cross-Reference vii

Service Construction Letter Attachment

Standard No.

Secondary

Underground

Multi-Lot Residential

Development Transformer

Pad

Precast Below-Grade

Vault In-Building

Vault Network

0100.04 x x x x x

0214.00 x x x x x x

0221.01 x x x x x x

0222.02 x x x x x

0222.04 x x x x x

0222.06 x x x x x

0223.03 x

0223.33 x x x x x x

0224.01 x x

0224.07 x x x x x

0224.34 x x x x x

0226.06 x x x x

0230.03 x x

0231.01 x x x

0231.03 x x

0257.06 x x

0257.47 x x

0461.10 x x x x x

0468.90 x x x x x

0473.50 x x x x

0474.08 x x

0674.06 x

0724.50 x x

0732.50 x x

0735.50 x

0751.00 x x

0751.49 x x

0751.60 x x

0751.77 x x

1553.03 x x x x x x

1554.33 x x x x x x

1554.42 x x x x x

1561.05 x x

1561.07 x x

1561.09 x

1611.05 x x x x x x D2-3 x x x x x

0257.49 x x NVH-80 x U2-11.40/NDK-40 x x x x x x U2-14.2 x x x x U2-15.1 x x x U2-22 x

Continued on the next page

Service Construction Letter Attachment Cross-Reference viii

Service Construction Letter Attachment

Standard No.

Secondary

Underground

Multi-Lot Residential

Development Transformer

Pad

Precast Below-Grade

Vault In-Building

Vault Network

6103.90 x x x x x

6762.25 x x x x x

6836.2 x

6836.3 x

6836.50 x

6836.6 x

7005.05 x x x x x x

7015.05 x x x x x x

7015.80 x x x x x

7050.05 x x x x x x

7050.09 x x

7050.11 x x x x x x

7055.09 x x x x x

7150.00 x x x x

7203.01 x x x

7203.04 x x x

7203.08 x x x

7203.10 x x

7203.12 x x

7203.21 x x x x x x

7203.26 x x x

7203.31 x x

7203.36 x x

7203.38 x x x x

7203.41 x x x x

7203.46 x x

7203.51 x x

7203.66 x x x

7203.76 x

7645.30 x x x x x x

7645.40 x x x x x x

7651.25 x x

CONSTRUCTION STANDARD

Standard Number:

Superseding:

Effective Date:

Page:

0130.30 November 5, 2019 June 7, 2022

Standard Coordinator Ponet Neuansourinh

Standards Engineering Supervisor John Shipek

Division Director Tamara Jenkins

Secondary Service Drops

1. Scope

This standard covers the information necessary to install overhead secondary service drop conductors (“service drops”) to buildings in the Seattle City Light (SCL) Looped Radial Distribution System.

2. Application

This standard provides direction to SCL engineers, crews, and approved contractors for the installation of service drops.

For installing secondary spans, see SCL 0130.10

For installing bridles for secondary service, see SCL 0130.20.

For LR bracket installation, see SCL 0100.11.

For service meter mounting configurations, heights, working space, and clearances, see

SCL 1554.33.

3. Requirements

3.1 Clearances

3.1.1. Vertical Clearances Between Service Conductor and Communication Cable

Vertical clearances between the service drop and communication drop, anywhere in the span to the building attachments, shall be per Table 3.1.1.

Table 3.1.1. Vertical Clearance between Service Conductor and Communication Cable

Location Clearance, Minimum (in) At pole attachments 40 In span or at building (including drip loop) 12

3.1.2. Vertical Clearances in the Span

The point of attachment at the pole or service entrance shall be high enough above the ground to meet the required minimum vertical clearances along service drop spans to ground, roadways, alleys, driveways, porches, balconies, windows, doors, or roofs as shown in Table 3.1.2. and Figure 3.1.2.

Secondary Service Drops

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Table 3.1.2. Vertical Clearances in the Span

Location Clearance, minimum (ft) Above bridges, highways, and railroads 24 Above roads, streets, driveways, parking lots, alleys, and spaces subject to truck traffic 16 Above sidewalks, final grade, and space not subject to truck traffic 12

Figure 3.1.2. Vertical Clearances in the Spans

Secondary Service Drops

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3.1.3. Clearances for Service Drop Terminations at the Support Mast on a Roof

Minimum required clearances for service drop terminations at the support mast on a roof are as shown in Table 3.1.3. and Figure 3.1.3.

Table 3.1.3. Clearances of Service Drops Terminating at the Support Mast on a Roof

Location Clearance, minimum Between the roof and the drip loop 18 in Between the top of the weatherhead and the rigid clevis (strike) 8 in Above the roof outside of a 6-ft radius from the service mast 3 ft

Figure 3.1.3. Clearances of Service Drops Terminating on a Support Mast, Profile View (left) and Plan View (right)

Secondary Service Drops

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3.1.4. Clearances for Service Drops Terminating on the Side of a Building

Minimum required clearances for service drops terminating on the side of a building shall be as shown in Table 3.1.4 and figures 3.1.4a–c.

Table 3.1.4. Clearances of Service Drops Terminating on the Side of a Building

Location Clearance, minimum In all directions when not attached to, or passing by, structures up to the strike point on a building

5 ft

Below, and to the sides of, balconies, decks, or similar locations 3 ft In all directions between windows and doors Exceptions:

o Where the service drop is above the top level of the window o Where a window is designed not to open

3 ft

Above base of balconies, decks, or similar locations 11 ft Horizontally from the building wall to which the service drop is attached 1 in

Figure 3.1.4a. Clearances from Doors

Secondary Service Drops

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Figure 3.1.4b. Clearances from Windows (Operable)

Figure 3.1.4c. Clearances from Balconies, Decks, or Similar Locations (ft)

Secondary Service Drops

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3.2 Installation

Weatherheads shall be installed no higher than 20 ft above final grade.

The customer shall furnish and install all required service entrance equipment up to the point of connection or demarcation per WAC 296-46B-230.

Only one service drop shall be allowed per service mast.

Service drops shall be installed as shown in Figure 3.2a.

Service drops shall be cleared and maintained, free of obstruction, by the customer.

Only power service drop conductors shall be permitted to be attached to a service mast.

Figure. 3.2a. Service Drop Installation Details

Guying or bracing of the roof support mast is required if the mast exceeds 26 inches above the roof line or if the service drop is longer than 100 ft. See WAC 296- 46B-230 for installation details.

The roof support mast shall be located no greater than 4 ft from the nearest roof edge.

Communication service drops shall not be permitted on the service mast (above or below roof).

For multiple service connections at the service entrance or at the pole, multi-tap insulated connectors shall be used as follows:

Three (3) multi-tap connectors for triplex

Four (4) multi-tap connectors for quadruplex

Secondary Service Drops

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Figure 3.2b. Multi-Tap Insulated Connector, Stock. Nos. 013661 or 013662

4. Construction Notes

For variances, pole guying, and clearances over structures and objects not listed in this standard, such as swimming pools and trolley conductors, consult with an SCL engineer.

Run continuous service conductor if possible.

Do not string service conductor to buildings at a tension that requires the use of automatic or straight-line clamps.

Secondary Service Drops

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5. Material Lists

Table 5a. Service Conductors, Overhead

Fig Compatible Unit ID Quantity

3.2a Wire, 350 kcmil Quadruplex Service CNDOSVC1-350QP

3.2a Wire, 4/0 Triplex Service CNDOSVC1-4/0TP

3.2a Wire, 4/0 Quadruplex Service CNDOSVC1-4/0QP

3.2a Wire, 1/0 Triplex Service CNDOSVC1-1/0TP

3.2a Wire, 1/0 Quadruplex Service CNDOSVC1-1/OQP

3.2a Wire, #2 AWG Triplex Service CNDOSVC1-#2TP

3.2a Wire, #2 AWG Quadruplex Service CNDOSVC1-#2QP

# Material Description ID 1 #2 AWG quadruplex 600734 1 – – – – – –

1 #2 AWG triplex 600672 – 1 – – – – –

1 1/0 quadruplex 600735 – – 1 – – – –

1 1/0 triplex 600664 – – – 1 – – –

1 4/0 quadruplex 600738 – – – – 1 – –

1 4/0 triplex 600669 – – – – – 1 –

1 350 kcmil quadruplex 600741 – – – – – – 1

Secondary Service Drops

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Table 5b. Service Connectors, Overhead

3.2a Connectors, 350 kcmil Quadruplex Service CNDOSVC1-350QPC

3.2a Connectors, 4/0 Triplex Service CNDOSVC1-4/0TPC

3.2a Connectors, 4/0 Quadruplex Service CNDOSVC1-4/0QPC

3.2a Connectors, 1/0 Triplex Service CNDOSVC1-1/0TPC

3.2a Connectors 1/0 Quadruplex Service CNDOSVC1-1/0QPC

3.2a Connectors, #2 AWG Triplex Service CNDOSVC1-#2TPC

3.2a Connectors, #2 AWG Quadruplex Service CNDOSVC1-#2QPC

2 Neutral service wedge clamp, #6 AWG–#2 AWG 581340 2 2 – – – – – 2 Neutral service wedge clamp, #4 AWG–1/0 581342 – – 2 2 2 2 2 2 Neutral service wedge clamp, 2/0–4/0 581344 – – – – 2 2 2 3 Connector, comp., bare, #4 AWG–4/0 650104 4 3 4 3 – 2 – 3 Connector, comp., insulated, yellow–yellow 650569 – – 3 – – –

3 Connector, comp., insulated, yellow–red 650565 – 3 4 – – – –

3 Connector, comp., insulated, red–red 650564 4 – – – – – –

4 Connector, comp., bare, 4/0–477 kcmil 650138 – – – – 8 4 8 5 Connector, 2-bolt, bronze, clamp, 1/0–4/0 str. 669380 2 2 2 2 2 2 2

Secondary Service Drops

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Table 5c. Service Connectors, Multi-Tap

3.2b Conn., Multi-Tap, #2 AWG–350 kcmil, 4-Position, TP JMULT3-1K-4OH

3.2b Conn., Multi-Tap, #2 AWG–350 kcmil, 4-Position, QP JMULT4-1K-4OH

3.2b Conn., Multi-Tap, #2 AWG–350 kcmil, 6-Position, TP JMULT3-1K-6OH

3.2b Conn., Multi-Tap, #2 AWG–350 kcmil, 6-Position, QP JMULT4-1K-6OH

3 Conn., multi-tap, #2 AWG‒350 kcmil, 4-position 013661 – – 4 3 3 Conn., multi-tap, #2 AWG‒350 kcmil, 6-position 013662 4 3 – –

6. References

SCL Construction Standard 0100.11; “LR Bracket Installation”

SCL Construction Standard 0130.10; “Secondary Service Span”

SCL Construction Standard 0130.20; “Secondary Service Bridle”

SCL Construction Standard 1554.33; “Meter Mounting Configurations, Heights, Working Space, and Clearances, Exterior (Outdoor)”

WAC 296-46B-230; Wiring and protection–Services

7. Sources

IEEE C2-2017; National Electric Safety Code (NESC); 2017

NFPA-70, National Electric Code (NEC) Article 230, Fourteenth Edition, National Fire Protection Association, Quincy, MA, 2017

Washington Administrative Code (WAC) 296-307-36609; “What Requirements Apply to Conductors”

Washington Administrative Code (WAC) 468-34-209; “Vertical Clearance”

Revised Code of Washington (RCW) 19.29.010; “Inspections‒Notice to repair and change‒Disconnection‒Entry‒Concealment‒Accessibility‒Connection to utility‒Permits, fees‒Limitation‒Waiver of provisions during state of emergency”

Neuansourinh, Ponet; SCL Standards Engineer, subject matter expert, and originator of 0130.30

Lu, Curtis; SCL Standards Engineer and subject matter expert for 0130.30

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0214.00 October 22, 2021 November 4, 2022

Standard Coordinator Brett Hanson

Standards Engineering Supervisor John Shipek

Division Director Andrew Strong

Clearances Between SCL Underground Assets and Non-SCL Structures and Objects

1. Table of Contents

2. Scope

3. Application

4. Design and Construction Notes

4.1 Covers/Hatch

4.2 Vault Knockouts

Figure 4.2a. Knockout Zone, Plan View Figure 4.2b. Knockout Zone, Elevation View

4.3 Shoring

4.4 Overhead Clearance for SCL Underground Structures

4.5 Access and Working Space for SCL Underground Structures

5. Minimum Clearances in the Right-of-Way between SCL Vaults or Handholes and Non-SCL Facilities, Conduits, and Pipes Figure 5a. Minimum Horizontal Clearance, Plan View Figure 5b. Minimum Horizontal Clearance, Elevation, Side View

6. Minimum Clearances in the Right-of-Way between SCL Conduits or Duct Banks and Non-SCL Facilities, Conduits, and Pipes Figure 6a. Minimum Horizontal Clearance, Non-Water Structures, Plan View ... 7 Figure 6b. Minimum Horizontal Clearance, Water Structures, Plan View Figure 6c. Minimum Vertical Clearance, Elevation View

7. Minimum Clearances on Private Property, between SCL Conduits or Duct Banks and Non-SCL Facilities, Conduits, and Pipes Figure 7. Minimum Horizontal Clearance, Plan View

8. Minimum Clearances in the Right-of-Way between SCL Structures and Vegetation 11 Figure 8a. Vegetation Clearance, Plan View Figure 8b. Vegetation Clearance, Elevation View

Clearances Between SCL Underground Assets and Non-SCL Structures and Objects

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9. Minimum Clearances in the Right-of-Way between SCL Underground Assets and

Various Other Non-SCL Structures and Objects Table 9a. Minimum Horizontal Clearances Between SCL Wood Poles and

Non-SCL Structures and Objects Table 9b. Minimum Horizontal Clearances Between SCL Assets (except SCL wood poles) and Various Other Non-SCL Structures and Objects Preferred Location

10. Location and Orientation of Vaults and Secondary Handholes at Grade

10.1 577 Vaults Figure 10.1.1 Preferred Location and Orientation for 577 Vault Figure 10.1.2 Alternate Location and Orientation for 577 Vault Figure 10.1.3 Location and Orientation for 577 Vaults with Junction Boxes . . . 15

10.2 Secondary Handholes

Figure 10.2.1 Preferred Location for Secondary Handhole Figure 10.2.2 Alternate Location for Secondary Handhole

11. References

12. Sources

2. Scope

This standard covers clearance requirements between Seattle City Light (SCL) underground assets and non-SCL structures and objects. This includes cases in the public right-of-way, on private property, in the Network service area, and the Looped Radial service area.

SCL underground assets include (but are not limited to) vaults, covers/hatches, handholes, duct banks, conduits, and the buried parts of wood poles.

Non-SCL structures and objects include (but are not limited to) basins, covers/hatches, pipes (gas, water, sewer, steam), conduit (telephone, cable TV, fiber optics), fire hydrants, water meters, street curbing, and root balls.

3. Application

This standard shall be used by SCL engineers, operations personnel, consultants, and contractors when designing and/or constructing vaults, handholes, conduits below grade that are in the vicinities of other utilities installations. These could be gas, water, sewer, steam, telephone, cable TV, and fiber optics. Other utilities and contractors should also follow these provisions when installing their facilities near any SCL facility.

Reasons for maintaining these minimum clearances are for allowing enough space for future equipment maintenance, assuring a safe environment to the public, avoiding thermal interferences between cables, repair and replacement of other utilities, and minimizing impact of other utilities failures on SCL equipment and vice versa.

The minimum clearances defined in this document are per SCL specifications taking into account the City of Seattle Land Use Code, Right-of-Way Improvement Manual, and Standard Plans and Specifications; and the Washington Administrative Code (WAC).

SCL specifications are derived from engineering and operations experience.

For any deviation from the prescribed clearances, an agreement has to be reached between SCL Engineering and the interested parties.

Clearances Between SCL Underground Assets and Non-SCL Structures and Objects

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4. Design and Construction Notes

Covers/Hatch When reviewing designs, engineers should take into account cover or lid size for future needs.

Vault Knockouts The knockout zone shall be eight feet long and the width shall equal the width of the knockouts plus 2 ft. The height of the knockout zone shall be equal to the height of the SCL facility. This zone should be reserved for future extensions of SCL duct runs unless parties receive explicit permission from SCL Engineering.

Non-SCL utility vault construction in knockout zones shall be approved by SCL Engineering. These zones are planned for future conduit extensions. See Figure 4.2a.

No utility handholes or other underground structures shall be installed in the area outside and adjacent to knockouts. See Figure 4.2a.

No installations below SCL facilities shall occur without written SCL Engineering approval. See Figure 4.2b.

No installations above other existing utilities’ structures shall occur without written SCL Engineering approval. See Figure 4.2b.

Figure 4.2a. Knockout Zone, Plan View

Clearances Between SCL Underground Assets and Non-SCL Structures and Objects

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Figure 4.2b. Knockout Zone, Elevation View

Shoring During construction projects shoring piles and shoring lagging shall maintain a clearance from SCL conduits, duct banks, handholes and vaults of at least 1 ft.

Overhead Clearance for SCL Underground Structures To allow crane access to SCL vaults for lowering and raising equipment, the minimum vertical height above the underground facilities, of overhead structures and any encumbrances, such as roadway columns, shall be 25 ft.

Access and Working Space for SCL Underground Structures To allow crane access to SCL vaults, facilities must be located to allow permanent SCL vehicular (truck) access to the facility for installation and service of electrical equipment.

SCL facilities must have a permanent, level, unobstructed, 8-ft wide working area adjacent to the facility for access to the facility and knockout zones.

Clearances Between SCL Underground Assets and Non-SCL Structures and Objects

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5. Minimum Clearances in the Right-of-Way between SCL Vaults or Handholes and Non-SCL Facilities, Conduits and Pipes

Non-SCL conduit can be 3 ft from SCL facility but must be below knockout zone.

If SCL knockout zones are planned for 115 kV or 230 kV facilities, horizontal clearance shall be 5 ft from SCL facilities to non-SCL facilities and conduits (except for high pressure steam or heat source).

Figure 5a. Minimum Horizontal Clearance, Plan View

Clearances Between SCL Underground Assets and Non-SCL Structures and Objects

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0214.00 October 22, 2021

Figure 5b. Minimum Horizontal Clearance, Elevation, Side View

Note: If SCL knockout zones are planned for 115 kV or 230 kV, horizontal clearance shall be at least 5 fit between SCL knockout zones and non-SCL conduit or pipes.

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6. Minimum Clearances in the Right-of-Way between SCL Conduits or Duct Banks and Non-SCL Facilities, Conduits and Pipes

If SCL conduit or duct bank contains 115 kV or 230 kV, the horizontal clearance between SCL facilities and non-SCL facilities shall be a minimum of 5 ft and the vertical clearance shall be a minimum of 1 ft.

Figure 6a. Minimum Horizontal Clearance, Non-Water Structures, Plan View

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Figure 6b. Minimum Horizontal Clearance, Water Structures, Plan View

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Figure 6c. Minimum Vertical Clearance, Elevation View

Notes

1. High pressure steam log or any heat source shall not cross SCL conduit or duct bank without SCL Engineering approval.

2. Vertical clearance applies to conduits crossing perpendicular underneath SCL conduits or duct banks. Non-SCL conduits are not allowed to be installed directly above or below parallel to SCL conduits or duct banks.

3. Crossing of sewer, storm, or water shall be perpendicular, except with written approval from SCL Engineering.

4. Backfill and bedding shall be installed as specified in Standard Plan 350 or 285, or per other AHJ.

5. Crossing under water, sewer, or storm laterals or mains requires support plan approved by the appropriate water AHJ and observation by that AHJ’s construction management.

6. Conduit crossing over water, sewer, or storm laterals or mains shall be reinforced for a minimum of 5 ft to either side. See SCL

U2-11.2/NDK-20.

7. Water, sewer, storm AHJ shall be notified when any cast iron pipe is exposed.

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7. Minimum Clearances on Private Property between SCL Facilities, Conduits, and Duct Banks and

Non-SCL Facilities, Conduits, and Pipes

Figure 7. Minimum Horizontal Clearances, Plan View

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8. Minimum Clearances in the Right-of-Way between SCL Structures and Vegetation

There shall not be any planted trees, bushes, or shrubbery within 2 ft of SCL vaults, handholes, conduits, and duct banks. The distance shall be measured from the vegetation’s root ball to the structure’s knockout zone.

Figure 8a. Vegetation Clearance, Plan View

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Figure 8b. Vegetation Clearance, Elevation View

9. Minimum Horizontal Clearances in the Right-of-Way between SCL Underground Assets and Various Other Non-SCL Structures and Objects

No installation is allowed directly above or below SCL facilities without written SCL Engineering approval.

For setback or clearance requirements from bioretention cells and rain gardens, see Seattle Rights-of-Way Improvement Manual Chapter 4, 4.17.5.

Table 9a. Minimum Horizontal Clearances Between SCL Wood Poles and Non-SCL Structures and Objects

Non-SCL Structures and Objects Horizontal Clearance from SCL Wood Poles (ft) Below-grade utility lines (e.g., pipes and conduits) 4 Below-grade utility structures (e.g., handholes and vaults) 10 Above-grade structures 5 Above-grade structures on the face/gain/equipment/brand side of the pole 10 Trees (measured from the center of the tree) 20

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Table 9b. Minimum Horizontal Clearances Between SCL Assets (except SCL wood poles) and Various Other Non-SCL Structures and Objects Various Other Non-SCL Structures and Objects Horizontal Clearance from SCL Assets (ft) Conduits or Duct

Banks Rated to 26 kV

Conduits or Duct Banks

Rated 115 or 230 kV Vaults or

Handholes Adjacent to Knockouts

Fire hydrants / water meters 3 5 3 8 Street curbing 1 5 2a – Building footings, building structures, and property lines

3 5 3b –

Metro bus poles and strain poles (overhead operations)

3 5 3 –

Concrete support columns 3 5 3 8 Concrete support column footings 3 5 3 8 Temporary construction shoring piles 1 1 1 1 Water maintenance holes 5 5 5 8 CBs and inlets 3 3 3 8 a To facility lid or hatch b For Looped Radial vaults intended to contain a transformer, the vault opening shall also be a minimum of 10 feet from all doorways, windows, stairways, and fire escapes.

10. Location and Orientation of Vaults and Secondary Handholes at Grade

577 Vaults 577 vaults are typically used as a pulling vault or a loadbreak vault. The purpose of specifying the location and orientation of the vault is to ensure proper working space for SCL operations personnel.

10.1.1 Preferred Location and Orientation

The preferred orientation for a 577 vault is the length of the vault perpendicular to the curb as shown in Figure 10.1.1. For 577 vaults with junction boxes, additional clearances are required. See Figure 10.1.3.

Figure 10.1.1 Preferred Location and Orientation for 577 Vault

The vented section of the vault shall be located in the sidewalk.

When installed within a planting strip, the top of vault shall be set 1/2 inch above surrounding grade. Slope grade away from vault for drainage.

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10.1.2 Alternate Location and Orientation

The alternate orientation for a 577 vault is the length of the vault parallel to the curb as shown in Figure 10.1.2. The location of the vault shall be entirely within the planting strip.

Figure 10.1.2. Alternate Location and Orientation for 577 Vault

When vault or handhole extends into the sidewalk area because of a narrow planting strip, the vault or handhole shall be located entirely in the sidewalk with the edge flush with the street edge of the sidewalk and to the sidewalk grade. This applies only to the alternate location.

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10.1.3 Location and Orientation for 577 Vaults with Junction Boxes

Additional clearances required for 577 vaults with junction boxes are shown in Figure 10.1.3.

Figure 10.1.3 Additional Clearances Required for 577 Vaults with Junction Boxes

Secondary Handholes

The secondary handhole shall be oriented with the long side of the handhole parallel to the curb. Lid shall open away from curbs and streets and avoid pedestrian and bike paths.

10.2.1 Preferred Location

The preferred location is within the planting strip as shown in Figure 10.2.1.

Figure 10.2.1. Preferred Location for Secondary Handhole

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10.2.2 Alternate Location

When there is lack of space in the planting strip, the alternate location for a secondary handhole is along the street side of the sidewalk, as shown in Figure 10.2.2.

Figure 10.2.2. Alternate Location for Secondary Handhole

Restore sidewalk per requirements in city of Seattle Standard Plans for Municipal Construction, Standard Plan No. 420 or other Authority Having Jurisdiction (AHJ).

11. References

SCL Construction Standard U2-11.2/NDK-20; “Reinforcement of Concrete-Encased Duct Runs”

SCL Construction Standard U2-14.2; “Vault Installation”

City of Seattle, Seattle Right-of-Way Improvement Manual

City of Seattle Standard Plans for Municipal Construction

City of Seattle Standard Specifications for Road, Bridge, and Municipal Construction

12. Sources

City of Seattle Standard Plan No. 030; “Standard Locations for Utilities (Residential Street)”

City of Seattle Standard Plan No. 285; “Pipe Bedding Sewer/Storm Drain”

City of Seattle Standard Plan No. 331; “Watermain Thrust Drain Blocking Horizontal Fittings”

City of Seattle Standard Plan No. 350; “Watermain Trench and Bedding”

City of Seattle Standard Spec 1-07.17(2); “Utility Clearances”

Hall, Alan; SCL Engineer and subject matter expert for 0214.00

NESC C2-2012, Part 3: “Safety Rules for Underground Lines”

Panomvana, Tanya; SCL Standards Engineer and originator of 0214.00

SCL Construction Guideline U2-10/NDK-50 (canceled); “Electrical Conduit and Facilities in Public Rights-of-Way”

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SCL Construction Guideline U9-6; “577 Vault with Three Loadbreak Junction Boxes – Installation, Grounding and Connections”

SCL Construction Standard 0232.05 (canceled); “Underground Residential Equipment Location of 577 Vaults and Secondary Handholes”

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0221.01 New April 1, 2020

Standards Coordinator Curtis Lu

Standards Supervisor John Shipek

Unit Director

Customer Requirements for Trenching in the Right-of-Way

1. Scope

This standard covers the customer requirements for trenching in the public right-of-way for underground electric service conduit installation.

Trenching in private property is outside the scope of this standard.

2. Application

This standard is for Seattle City Light (SCL) engineers, crews, Electric Service

Representatives (ESRs), Electric Service Engineers (ESEs), customers, and contractors who design and/or construct underground conduit that requires trenching in the public right-of-way.

3. Definitions

Trenching: Excavation, backfill and surface restoration necessary for the installation of conduit.

Public Right-of-Way: Property dedicated to public use outside of private property lines.

4. Requirements

4.1 General

Trenching in the public right-of-way within the SCL service area shall be done in accordance with SCL Standards and SCL Requirements Letter with job-specific requirements.

All work must also adhere to the requirements per the City of Seattle Right-of-Way

Improvements Manual, Streets Illustrated, and the City of Seattle Standard Plans for

Municipal Construction, which are the comprehensive resources for requirements, procedures, standards, and guidelines affecting physical changes in the public rights-of-way or the requirements of the authority having jurisdiction (AHJ) if outside

Seattle city limits.

All other project-related work, including excavation, backfill, and surface restoration shall also meet the requirements of the above-stated SCL standards and SCL Requirements

Letter with job-specific requirements.

A qualified SCL electrical worker is required as a safety standby whenever entry into an energized SCL facility is needed, regardless of the voltage.

Customer Requirements for Trenching in the Public Right-of-Way

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The customer/contractor shall be responsible for calling the “One-Call” locator service and for notifying all other utilities who may not subscribe to the One-Call locator service.

A toll-free number, 1-800-424-5555, or “811” is available for notifying most Seattle area utilities, including those located in King County. This does not relieve the customer/contractor from notifying all other utilities of the intent to excavate. The customer/ contractor must follow all the applicable state guidelines as specified in

RCW 19.122.

4.2 Permits

The customer/ contractor is responsible for obtaining necessary permits from the appropriate jurisdiction’s permit-issuing authority prior to commencing work.

SCL franchise cities and Unincorporated King County (UKC) areas served by SCL shall coordinate with the appropriate AHJ to obtain permits for their customers to trench in the public right-of-way as specified in the AHJ’s regulations.

If customers are not allowed to trench in the right-of-way by their respective county, franchise city, or UKC area, SCL will perform all service installation work per SCL’s work schedule in accordance with the Service Installations Policy, DPP 500 P III-417. SCL will obtain the permit and perform all civil construction work. This will be considered extraordinary work for which the customer shall be billed.

4.3 Administrative Charges

The contractor shall be responsible for administrative costs by the permit-issuing authority, and bonding requirements of both SCL and the permit-issuing authority.

SCL inspection and review charges, if applicable will be assessed in addition to those charged by other inspecting authorities.

4.4 Inspections

The customer/contractor is responsible for contacting an SCL Electric Service

Representative or Electric Service Engineer to schedule inspections to ensure all workmanship is done in accordance with SCL construction standards.

All post-trenching backfill and surface restoration work shall be inspected by the customer’s associated AHJ.

5. References

State of Washington, Underground Utilities Law, 2011; Chapter 263, codified in

Chapter 19.122 RCW

DPP 500 P III-417; Service Installations

City of Seattle Streets Illustrated Right-of-Way Improvements Manual

City of Seattle Standard Plans for Municipal Construction

6. Sources

Lu, Curtis; SCL Standards Engineer and originator of 0221.01 (curtis.lu@seattle.gov)

DPP 500 P III-424 (canceled) http://seattlerowim.wpengine.com/ https://www.seattle.gov/utilities/construction-and-development/standard-specs-plans mailto:curtis.lu@seattle.gov

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0222.02 October 22, 2021 October 5, 2022

Standards Engineering Supervisor John Shipek

Requirements for Primary Conduit and Duct Bank Installation

1. Table of Contents

2. Scope

3. Application

4. Requirements

4.1 General

4.2 Depth

4.3 Alignment

5. Primary Conduit and Duct Bank Construction

5.1 Arrangement

5.2 Termination

5.3 Changes in Direction

6. Conduits

7. Trench

8. Spacers

9. Encasement

10. Backfill

10.1 Types of Backfill

10.2 Requirements

11. Identification

12. Inspection

13. Communications

14. Additional Network Conduits

15. References

16. Sources

Requirements for Primary Conduit and Duct Bank Installation

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2. Scope

This standard provides the general requirements for the construction and installation of primary conduits and duct banks in the public right-of-way and on private property within the Seattle City Light (SCL) service territory. This includes system duct banks of more than two conduits, and primary service duct banks with only two conduits.

Job-specific requirements are not covered in this standard. Refer to the SCL Requirements Letter for job-specific requirements.

3. Application

This standard provides direction to SCL crews, engineers, customers, electrical service representatives, reviewers, inspectors, and contractors about where and how to properly install primary (601 – 50,000 V) conduits and all distribution duct banks in the public right-of-way and on private property.

For secondary (0 – 600 V) conduit installations, refer to SCL 0224.07.

For clearances between underground structures, refer to SCL 0214.00.

4. Requirements

4.1 General

Conduits and duct banks shall conform to Table 4.1 and Figures 4.3a and 4.3b.

Table 4.1. General Requirements

Function System Service Voltage 601 – 50,000 V 601 – 50,000 V Location Right-of-way and private property Right-of-way and private property

Area Network and Looped Radial Network and Looped Radial Cover (minimum) 36 in 36 in No. of Conduits (minimum) 2 2 Encasement Yes Yes Marking Tape Yes Yes Backfill CDF CDF

4.2 Depth

See Table 4.1 for minimum cover.

4.3 Alignment

Center line of the duct bank shall be located 15 feet from center line of street on either side of the street unless otherwise specified by the SCL engineer.

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Figure 4.3a. Primary Duct Bank, End View

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Figure 4.3b. Primary Duct Bank, Side View

5. Primary Conduit and Duct Bank Construction

Duct banks and conduit systems are electrical facilities for power distribution. In order for the electrical system to perform at its full capacity, the following requirements shall be met:

Systems shall be constructed in a neat and workmanlike manner.

All joints shall be tightly sealed against water intrusion. For transition joints (steel to PVC, steel to fiberglass) and set screw coupling joints, apply a layer of mastic tape (Stock No. 736470) and a layer of electrical tape (Stock No. 736656) on top.

All coupling and adapter threads shall be sealed with Oatey Great White pipe joint compound or equal with approval prior to installation.

All joints shall be properly aligned and square, and have adequate cure time.

All edges shall be deburred and chamfered to prevent damage to cables. See SCL 7015.05.

Conduit runs shall be adequately supported so they do not become distorted during encasement or backfill.

Conduit bends shall be concentric and maintain consistent spacing.

Set screw couplings shall be encased.

Installations that do not meet these criteria will be rejected.

5.1 Arrangement

5.1.1 Transposition

Conduits shall NOT be transposed between vaults.

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5.1.2 Numbering

The ducts shall be numbered separately by type; service ducts together and system ducts together. The numbering method shall be as follows:

For ducts running east-west, count from north to south and from top to bottom.

For ducts running north-south, count from west to east and from top to bottom.

Example shown in Figure 5.1.2.

Figure 5.1.2. Duct Numbering Example

5.2 Termination

5.2.1 Permanent

The first two feet of all conduits exiting the vault shall be vertically and horizontally perpendicular to the vault face. Conduits shall enter the vault no more than 18 inches from the adjacent wall.

If there are multiple duct banks or direct-buried conduits entering horizontally and at right angles to each other in the same corner of a vault, manhole, or handhole, they shall enter at different elevations so they are vertically offset to the other.

All duct terminations into vaults, handholes, etc., shall be done by core drill. Core size shall be one trade size larger than conduit trade size.

Provide and install PVC-type DB-120 conduit end bells flush with the interior walls on all conduits entering the vault. The conduits shall be grouted both inside and outside of the vault. See SCL 7055.09 for approved manufacturers.

For terminating existing ducts in new vaults, see SCL 0222.06.

5.2.2 Temporary

Install reinforcement steel dowels whenever placing of encasement is to be delayed beyond initial set.

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Spacers shall be placed as close to the temporary termination as possible in order to maintain proper conduit spacing.

Lower conduit shall be flush or protrude beyond the conduit above it to ease reattachment.

See Figure 5.2.2 for details.

Figure 5.2.2. Temporary Termination

5.3 Changes in Direction

Any changes in direction must consist of only one type of conduit material and all bends must have the radius of the largest conduit. See Table 5.3 for minimum bend radius requirements.

For a change in direction, the PVC conduit may be cold-formed, provided the deflection does not exceed 1 ft per 10-ft section.

For standard wall fiberglass conduit, lateral deflection shall not exceed 1 ft per 20-ft section.

Each conduit bend shall be mandreled prior to placement and encasement. See

SCL U2-11.40/NDK-40.

Conduits installed on private property must include a proper transition on the private property when meeting up with conduit in the right-of-way that requires a minimum 36-in cover.

Table 5.3. Minimum Bend Radius Conduit (in)

System1, 3

(in) Service2, 3

(in) Communication

(in)

2.5 – 24 – 3 144 36 – 4 144 48 48 5 150 60 – 6 144 60 –

Notes:

1 PVC conduit is not allowed for system conduit bends.

2 Bending PVC conduits with heat is not allowed.

3 Typical unless otherwise specified by SCL engineer.

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6. Conduits

Schedule 40 PVC, rigid steel or fiberglass conduits can be used in conduits and duct banks as specified in Table 6.

Table 6. Allowed Conduit Materials Schedule 40 PVC

(SCL 7015.05)

Rigid Steel (RGS)

(SCL 7050.05)

Fiberglass

(SCL 7025.05)

System – Straight No1 Yes Yes System – Bend No Yes No1 Primary Service – Straight Yes Yes Yes2 Primary Service – Bend No Yes No1 Communication – Straight End Bend Yes Yes No

1 Typical unless otherwise specified by SCL engineer.

2 Only for 5-inch conduits.

Conduits entering an in-building vault or within a building footprint shall be steel.

Conduits exposed under aerial structures (bridges, etc.) shall be steel and effectively grounded.

Conduits installed under, or through, wall or structural sections shall be steel.

Factory and field straight-cut ends shall be chamfered throughout the duct run. See SCL 7015.05.

The conduit shall be RGS if there is 10 ft or less between bends (except communication conduits).

Allow two hours minimum to cure conduit adhesive prior to encasement.

A spare conduit shall be provided. Conduit shall be run in pairs.

7. Trench

The bottom of the trench shall be free of debris and fine-graded by hand to remove sharp, embedded rocks and loose stones over 1/2 inches in size. Or, the trench shall be over-excavated and replaced with bedding material to cover protruding rocks and stones by a minimum of 2 in. The bottom shall be graded even. Bedding material shall be crushed rock.

There shall be no standing water in the trench and the trench shall not be saturated.

8. Spacers

Spacers for conduit separation shall be plastic lock-type (see SCL 7015.80) of such configuration to give the required separation between conduit and earth, as shown in Figure 4.3a.

Horizontally, spacers shall be placed a maximum of 5 ft apart in both straight and bending sections of duct banks and a minimum of one foot away from any coupling, fitting, or end bell, as shown in Figure…