Engineering, Procurement & Construction Services for Medium Voltage Metal-Clad Switchgear Replacement


“EPC Switchgear Specialists deliver significant savings in time and money”




This Paper will address new Project Engineering, management and execution choices in today’s specialized services business environment. Furthermore, we will touch upon new manufacturing technologies and the decision-making process for the replacement of installed, medium-voltage (2400V through 38kV), metal-clad switchgear and circuit breakers in a draw-out construction; relative to electrical power distribution systems typically found at utility power plants, Industrial and Manufacturing facilities.

The combination of the aging of this critical infrastructure equipment and the addition of new equipment and systems, on the service bus, causing increased power loading on the electrical distribution system is addressed. More importantly the safety, operational, compliance and environmental aspects brought on by NERC/FERC, OSHA/NFPA and EPA regulatory pressures have motivated many Owners to budget and Plan for the replacement of this original, medium-voltage, metal-clad switchgear equipment.

Furthermore, we will address safety compliance, environmental issues, technical specifics and project management decisions that can positively affect your Companies’ approach to a cost-effective remedy in replacing this existing, aged, Draw-out, metal-clad switchgear via a unique, engineered adaptation of new, Arc Resistant gear into existing systems with minimal impact on existing primary and secondary connections. Safety Hazards, reliability/Performance, Compliance and Environmental issues include the integrity and compliance of equipment performance and Operator exposure during Racking Operations which include NFPA 70E Arc Flash compliance; equipment reliability performance during the Racking Process; Exposure to asbestos (EPA) during Maintenance and Inspections on air-magnetic circuit breakers; Short Circuit Fault clearing capabilities and conditions affecting the integrity of the switchgear bus system, circuit breakers and overall electrical distribution system integrity and compliance. The engineering standard technical basis will rely upon ANSI accredited IEEE C37.20.7 for Type 2C arc-resistant switchgear.

Achieving these aforementioned goals with Cost-Savings and Project Timely Completion – EFFICIENCIES – are featured and defined.


The profile basis of this Paper will be electric utility, coal-fired power plants (250+MW); Auxiliary Unit 4kV Switchgear with (17) bays; the Owner is significantly concerned with the following:

Operator/Electrician’s direct exposure to Arc Flash energies during the Racking Process
The operational integrity and reliability of the Racking System components
The increase Loading on the Service Bus due to the addition of motors and distribution panels installed for previous emissions control equipment and the (in)ability for the existing circuit breakers to clear a short-circuit Fault condition
Spare parts and existing sub-assemblies’ operational integrity and reliability
Potential exposure to friable asbestos to their Electricians and Maintenance personnel when performing Inspections, testing and maintenance on their air-magnetic circuit breakers


Significant utility generating units’ often have system outage windows of four (4) to five (5) weeks. Typically, not enough time to complete any significant construction project or major equipment replacement. Setting aside appreciably more outage time can cost appreciably more money. Traditional tactics would include multiple decisions and significant planning – all which would require key Plant and/or Corporate resources. Critical issues such as the writing of equipment and installation Specifications or contracting of an Architectural & Engineering Firm; decide and determine the A&E’s Project Management Role; will the A&E hire and manage the General Contractor; the Electrical Contractor; the Third-Party Testing/Commissioning Company, and the equipment Manufacturer? As the Owner, the decision whether to pre-purchase all major Capital Equipment Assets is important, as well as managing the inter-action and planning between Plant Site personnel and any Contractor(s).

Other, traditional “wholesale” approaches incorporate the “demolition” of this type of equipment in a brute-force, tear-it-out manner. Without the deliberate, engineering evaluation conducted by Specialists and shared with the Owner; tremendous cost-efficiencies are not only overlooked – but additional, significant costs are piled-on needlessly. Economies of scale can be realized through project completion (time) and significant cost savings (dollars).

Major unit outages can run twenty-four (24) weeks or more; but are targeted for major Equipment Replacement/Restoration such as Turbine Generators, Boilers, etc. A concurrent, significant Asset Replacement would represent unique logistical challenges that are better off avoided.

All-the-while the Plant Operators and Electricians continue to be faced with significant safety, operational and compliance issues and the Plant/Corporate Engineer watches the system loading capacity dwindle.


The introductions of new technologies, such as vacuum bottles as the interrupting medium in medium-voltage circuit breakers, have delivered significant improvements to the operations, reliability and safety in today’s medium-voltage switchgear and circuit breakers. Furthermore, the application of Standards in Designs, such as Horizontal Racking Operations and Remote Racking Designs has dramatically improved Safety and Reliability. The latest improvement is the design and construction of Type 2 Arc Resistant Switchgear; providing an appreciable, “first-line” defense and control of arc flash energy potential within the switchgear System.

Recent, past methods and considerations represented a mere “band-aid” to these mounting challenges. Replacement Doors, Roll-In Replacement Circuit Breakers, Remote Racking systems and “fast-acting” Instantaneous Relays reflect a piece-meal approach which never fully addresses all of the issues. Put all of these “components” together and design them into Type 2 Arc Resistant Switchgear structure – now you have the complete, engineered Equipment Package.

Project Management and execution; utilizing a single-point of contact via an Engineer, Procure and Construct (EPC) Company can provide Project efficiencies. Consideration to taking the EPC concept a step further will produce greater efficiencies. Combining the engineering, procurement, project management and overall project resources of a traditional EPC with the experience, knowledge and laser-focus of a Switchgear Specialist, would be a combination that could deliver tremendous results. EPC Switchgear Specialist represents the complete Service Provider Package high-level Solution.


Basis Installation – Unit 1 and the existing, indoor switchgear (Bus 1B) with (17) Compartments and (15) 4160V; air-magnetic, draw-out circuit breakers with stored-energy mechanisms; traditional switchgear construction with metal doors, mounted Relays, Indicating lights, analog gauges, SB switch, external control circuit fuse block and door hasp/handle.

EPC Switchgear Specialist refers to only one Company, one point of contact, one Project Team, and “one Engineer of Record”. There are no layers of authority and organizations that bog down the decision-making process, impede Project expediency or accumulate field change orders – a significant economy of scale.

Design Review process begins by reviewing the Plants’ existing, installed equipment Drawings, Prints, Diagrams, Schematics, and Elevations. Key areas and issues are identified; approaches, methods and solutions are designed into the Project. New, Arc Resistant Switchgear manufacturing detail is then superimposed or redlined onto the existing detailed drawings; the complete recreation onto AutoCad (or equal) provides the first draft of “As Built” drawings. Confirmation is acquired through the detail review and thorough evaluation by EPC and Owner’s Project and Staff Engineering. Often, the Manufacturer is invited to assist in the melding of the new equipment detail into the existing Plant facilities. It is not uncommon to find 5kV class Service Bus to become overloaded due to emission controls and monitoring equipment and now, Engineering Fault and Load Studies uncover the need for 350MVA Rated circuit breakers and Service Bus. Additionally, system condition monitoring via metering and communications is asked for; zone isolation for fast acting Trips for maintenance and Protection schemes are being asked for.

Planning, scheduling and construction review process employs the Owner’s Project Team, Project Engineer and Plant Representative(s); and the EPC Switchgear Specialist Team which would include the Safety Director, Project Engineer, Project Manager, Field Supervisor, Material Manager and Manufacturers’ conformance representative.

New Type 2C Arc Resistant Switchgear is proposed per ANSI/IEEE C37.20 engineering standards. Type 2C Switchgear is widely considered to be the safest solution on the market to ensure personnel and property safety in the event of a fault and ensuing arc flash. In the event of an arc flash, Type 2 Switchgear is designed with a plenum at the top of the equipment to direct all energy away from the Operator/Personnel exposure Area; isolating damage to the faulted compartment only. All gases, ionized copper, panel debris and projectiles are funneled up and away – to a safe area.

This Type 2C Arc Resistant Switchgear will be manufactured to the exact footprint of the existing switchgear; confirmed through Drawing and Elevation Review and by double-checking the integrity of the Drawings versus Installation through a detailed and thorough Site visit at the Plant during the Design Review process. Another very important aspect of the Design Review at the Plant Site will include detailed Inspection of all power cable and accessories. This process will insure the integrity of the existing power cable system and the determination of accessory integrity such as terminations, lightening arrestors, ground/shield conductors and connections – the overall ability of the power cable system to be reconnected in an expedient manner with no compromise to the performance integrity of the existing power cable system. This approach shall eliminate the risk of inflicting any damage to the existing power cable system during the Project and assure the operational integrity after re-connection. Eliminating the need of replacing, splicing, bending and stretching NEW or existing power cable systems, including cable tray, duct and piping provides significant COST and TIME savings and efficiencies during the course of a Project of this magnitude.

The project schedule has been designed to allow ample time to complete all tasks within a four (4) week outage window. EPC will staff the onsite project work with ample personnel to complete the installation and commissioning. All personnel shall be safety trained to Client requirements and directed by an on-site EPC Project Manager via Owner/Project Manager with extensive background in similar project scopes. EPC will require a long track record of performing similar scope projects with other Investor Owned Utility Power Plants, Industrials and Manufacturing Facilities.


EPC Switchgear Specialist Project Team members will conduct all required Owner Safety and Access Training and Certifications. Engineers and service technicians possess the skills and knowledge to safely test, evaluate, service and recondition electrical apparatus. Employees are Drug Free and OSHA safety trained. Any analysis and engineering recommendations will be provided by a State Certified Professional Engineer, electrical engineer.

Site specific Construction labor will be staffed by EPC Switchgear Specialist directly employed engineers, project managers and technicians during the course of this project, unless approved otherwise by Owner.

Concrete foundations appear to be able to be reused in their current condition.

The installation is based upon reusing all load side conductors. If cable is to be supplied, spliced or routed additional material and work scope will apply. Design objectives allow all cables to match up to the new sections with no modifications. Terminations are assumed to be reused, no termination kits are supplied. Applicable control wiring cabling systems can be minimally modified or affected without performance integrity compromise.

Field Function testing of the relays and breakers is included in this scope.

Field Engineering and Field Project Management are included in the Field Technical Services breakout documents. Design Engineering is represented in the Engineering breakout documents.

All mains and feeders will be circuit breakers.

EPC will include the Owner provided coordination and system modeling and curves with Power Analytics (or approved equal) software. Only the protective relays that are provided as part of this proposal are included. EPC will coordinate the relays supplied with their corresponding upstream protective devices and downstream protected loads. This service will be provided according to Client Standards. Client will provide all existing information available to direct (assist) in this modeling.

EPC will supply all project schedules utilizing a mutually agreed upon Project Management software package.


Compartment structures, cell structures, plenums, circuit breakers, doors, devices, bus systems, sensors and associated components will be inspected, pre-tested, pre-assembled and organized into a “kit” format previous to shipment to the Site. This process will be made available for Witness Inspection and Review to the Owner.

All Assemblies, systems and components will be Witness Inspected and Tested (again) at the Site; component level and System Assembled.

All engineering data shall show equipment as specified and ordered. Engineering data, as listed below, shall be supplied electronically as listed:

  • Master Drawing Index
  • System single line drawing
  • Section view drawing
  • 3-phase elementary
  • Schematic diagrams
  • Nameplate drawing
  • Instrument layout
  • Bills of material
  • Acceptance testing documents and reports
  • Final relay setting files will be provided in documentation package; based upon existing Protective Device Settings or as provided by the Owner

Drawing Requirements

  • AutoCAD Version 2007 or greater supplied for all drawings.
  • Electronic drawing PDF format files for approval shall be supplied.
  • Structural Drawings, with critical dimensions, showing:
    • Arrangement.
    • Plan, front view, and elevation section views.
    • Required clearances for opening doors and for removing breakers.
    • Bus Duct connection diagrams for main breakers and tie breakers.
    • Incoming and outgoing power cable terminator positions.
    • Grounding connections.
    • Weight of equipment.

Drawings shall indicate all equipment, but only such equipment, as is actually in the scope of supply. All user connection and interface points shall be clearly marked, including primary and secondary cable entrances and connection points, installation details, generic interframe assembly and generic connection details for shipping splits.

Elementary Three-Line and One-Line Diagrams

  • Three line diagrams, with ANSI device function numbers used throughout, shall show all:
    • Instrument transformers.
    • Relays.
    • Meters and meter switches.
    • Breakers and other pertinent devices.
  • One line diagram(s), showing overall Power System, predicated on existing, accurate Power System One-Line.

Schematic Diagrams

  • Schematic diagrams shall be furnished for the electrically operated breaker / relay control scheme.
  • Each schematic diagram shall show all control devices and device contact, each of which shall be labeled with its proper ANSI device function number.
  • Each schematic diagram shall show device and terminal block terminal numbers for customer connections.
  • Provide control switch development tables.
  • Detailed Connection (Wiring) Diagrams showing, submitted for record only:
  • Approximate physical location of all items in each unit.
  • All wiring within each unit.
  • All interconnecting wiring between units.
  • Identification of all terminals, terminal blocks, and wires.
  • Provide one set of drawings shipped with the equipment for start-up use.


  • Safety
  • Reliability
  • Compliance
  • Savings


Employee and Operations achievements are delivered NOW. Providing worker Safety should not wait; Arc Resistant Switchgear Replacement by an EPC Switchgear Specialist can be budgeted, planned and executed without delay without any excuses. NFPA and OSHA Safety issues relative to medium-voltage switchgear are eliminated. System Reliability improvements via new technologies; Type 2 Arc Resistant Switchgear; Vacuum Bottle Interrupters; Intelligent Electrical Devices/Relays communicate system conditions and coordinate Protection, Control and Communications. Regulatory Compliance issues are completed, installed and on-line. Environmentally, all asbestos arc-chutes will be disposed of. NERC/FERC Compliance requirements – now and in the future – are met. Significant Cost Savings are realized utilizing a single, laser-focused Partner in an EPC Switchgear Specialist. Extensive Planning; Speed in Design Review and Scheduling; Speed in the Decision-Making process; Speed of Execution / Installation – all without COMPROMISE – equals significant COST SAVINGS.


Today’s Utility Power Plants, Industrial and Manufacturing Facilities are faced with a barrage of significant regulatory, safety, environmental, operational and technological pressures to keep their Plants and Facilities safe and cost efficient. As technologies and systems advance, so do the Project Management, Engineering and Service Providers – as Specialists. Leveraging Specialists, as partners, assures that your Company maintains a leadership position in safety, compliance and leading-edge technologies in the most cost-effective manner possible.