Underground Electrical Distribution Systems

Upcoming dates (1)

Oct. 1-3, 2024

Madison, WI

Course Overview

This course will introduce you to the components in underground electrical distribution systems. We'll help broaden your understanding of the entire system and employee responsibilities, including planning, design, operation, and maintenance.

Learn from an industry-leading engineer in underground (UG) utility distribution cable systems (shielded cable, terminations, separable connectors, etc) and another in UG equipment and devices (transformers, switches, fuses, etc), who both have a career's-worth of application knowledge.

This course is intended to give all attendees a well-rounded understanding of electric utility primary UG distribution systems and the associated organizational responsibilities.

Who Should Attend?

You will benefit if you work in the areas of planning, design, construction, operation, maintenance, or safety of medium-voltage underground electrical distribution systems in a utility or institutional setting.

Course Outline

Introduction to Underground Distribution

  • Planning considerations
  • Introduction to UG equipment types and applications
  • Device-locating and system-layout philosophies
  • Policy considerations and examples
  • Terms and conditions of customer interconnection and service
  • Easements and ownership of facilities
  • Industry codes/standards, cost recovery methods 

Planning and Design Criteria 

  • Transformer loading
  • Circuit capacity ratings and configurations 
  • Circuit switch and protection
  • Voltage regulation and surge protection
  • Intro to Strategic Undergrounding

Underground Cable

  • Cable theory and construction
  • Electrical and mechanical properties
  • Conductor and insulation types
  • Selection, ratings, and loading practices

Cable Accessories

  • Voltage stress relief
  • Terminators and splices
  • Selection, ratings, and installation practices

Underground Structures

  • Direct burial trenches, conduits and ducts, vaults and manholes
  • Riser poles
  • Technical specifications and installation practices 

Pad-Mounted and Submersible Equipment

  • Transformers, switches, fuses, and lightning arresters
  • Selection ratings
  • Installation practices

 Cable Installation in Underground Structures

  • Cable pulling limitations and calculations 
  • Pulling equipment and methods

National Electrical Safety Code (NESC®) Requirements, Including Notable Applicable Provisions of the 2017 Edition of the NESC

  • General requirements
  • Grounding and safety rules for UG systems

Cable Testing and Maintenance

  • Why cables fail
  • Test methods
  • Maintenance options
  • Rejuvenation

Pad-Mount Transformer Specification

Overvoltage (Lightning) Protection on Underground Systems

  • Nature of lightning and switching impulses
  • Effective Grounding
  • Basic insulation level (BIL)
  • Insulation coordination
  • Arrester theory and design/selection and application 

Overcurrent Protection on Underground Systems

  • Types and characteristics of faults
  • Fuse selection and coordination 
    (will come with fuse selection exercise) 

 Operation and Maintenance of Underground Systems

  • Cable locating and marking
  • Switching operations
  • Cable replacement vs. rejuvenation 
  • Physical and infrared testing of equipment
  • Preventive maintenance methods


Michael Smalley

Mike Smalley has 28 years of electric utility engineering experience. The last 20 years have been focused on underground electrical distribution materials and standards, with a primary responsibility of low and medium-voltage underground cable systems. He is a senior member of the IEEE insulated conductors committee and a past chair of the AEIC cable engineering committee. He received a B.S. in electrical engineering technology from the Milwaukee School of Engineering, and a M.S. in engineering from the University of Wisconsin-Milwaukee. Mike is a registered professional engineer in the state of Wisconsin.

Thomas Callsen

Thomas Callsen has over 30 years of related utility experience. During his 25 years at Commonwealth Edison Company (ComEd), Thomas held numerous engineering roles, culminating as a principal engineer/consulting engineer in the distribution standards department where he was responsible for distribution transformers, capacitors, fuses, reclosers and distribution automation hardware. In 2006 Thomas received DistribuTECH’s prestigious “Project of the Year Award” for his “Distribution Center in a Box” substation. In 2009 he received the award again for industry’s first real-time overhead fault indicator communicating over a mesh network radio system. (Both products are now commercially available.) He received a US patent for the invention of the DC in a Box transformer design. Thomas is a senior member of the IEEE and an active member of the IEEE transformer committee that writes the industry standards for transformers in North America. Thomas holds a BSEE from the University of Wisconsin–Milwaukee and is a licensed professional engineer.

Upcoming dates (1)

Program Director

Kevin Rogers

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