36C24518Q0120-002.pdf

For the best experience, open this PDF portfolio in

Acrobat X or Adobe Reader X, or later.

Get Adobe Reader Now!

http://www.adobe.com/go/reader

26 05 26 - 1

SECTION 26 05 26

GROUNDING AND BONDING FOR ELECTRICAL SYSTEMS

PART 1 - GENERAL

1.1 DESCRIPTION

A. This section specifies the furnishing, installation, connection, and testing of grounding and bonding equipment, indicated as grounding equipment in this section.

B. “Grounding electrode system” refers to grounding electrode conductors and all electrodes required or allowed by NEC, as well as made, supplementary, and lightning protection system grounding electrodes.

C. The terms “connect” and “bond” are used interchangeably in this section and have the same meaning.

1.2 RELATED WORK

A. Section 26 05 11, REQUIREMENTS FOR ELECTRICAL INSTALLATIONS:

Requirements that apply to all sections of Division 26.

B. Section 26 05 13, MEDIUM-VOLTAGE CABLES: Medium-voltage cables.

C. Section 26 05 19, LOW-VOLTAGE ELECTRICAL POWER CONDUCTORS AND CABLES:

Low-voltage conductors.

D. Section 26 05 73, OVERCURRENT PROTECTIVE DEVICE COORDINATION STUDY:

Short circuit, coordination and arc-flash study, and requirements for a coordinated electrical system.

E. Section 26 11 16, SECONDARY UNIT SUBSTATIONS.

F. Section 26 12 19, PAD-MOUNTED, LIQUID-FILLED, MEDIUM-VOLTAGE

TRANSFORMERS.

1.3 QUALITY ASSURANCE

A. Quality Assurance shall be in accordance with Paragraph, QUALIFICATIONS

(PRODUCTS AND SERVICES) in Section 26 05 11, REQUIREMENTS FOR

ELECTRICAL INSTALLATIONS.

1.4 SUBMITTALS

A. Submit in accordance with Paragraph, SUBMITTALS in Section 26 05 11, REQUIREMENTS FOR ELECTRICAL INSTALLATIONS, and the following requirements:

1. Shop Drawings:

a. Submit sufficient information to demonstrate compliance with drawings and specifications.

b. Submit plans showing the location of system grounding electrodes and connections, and the routing of aboveground and underground grounding electrode conductors.

26 05 26 - 2

2. Test Reports:

a. Two weeks prior to the final inspection, submit ground resistance field test reports to the COR.

3. Certifications:

a. Certification by the Contractor that the grounding equipment has been properly installed and tested.

1.5 APPLICABLE PUBLICATIONS

A. Publications listed below (including amendments, addenda, revisions, supplements, and errata) form a part of this specification to the extent referenced. Publications are referenced in the text by designation only.

B. American Society for Testing and Materials (ASTM):

B1-13...................Standard Specification for Hard-Drawn Copper

Wire

B3-13...................Standard Specification for Soft or Annealed

Copper Wire

B8-11...................Standard Specification for Concentric-Lay-

Stranded Copper Conductors, Hard, Medium-Hard, or Soft

C. Institute of Electrical and Electronics Engineers, Inc. (IEEE):

81-12...................IEEE Guide for Measuring Earth Resistivity, Ground Impedance, and Earth Surface Potentials of a Ground System Part 1: Normal Measurements

D. National Fire Protection Association (NFPA):

70-17...................National Electrical Code (NEC)

70E-15..................National Electrical Safety Code

99-15...................Health Care Facilities

E. Underwriters Laboratories, Inc. (UL):

44-14 ..................Thermoset-Insulated Wires and Cables

83-14 ..................Thermoplastic-Insulated Wires and Cables

467-13 .................Grounding and Bonding Equipment

PART 2 - PRODUCTS

2.1 GROUNDING AND BONDING CONDUCTORS

A. Equipment grounding conductors shall be insulated stranded copper, except that sizes No. 10 AWG and smaller shall be solid copper.

Insulation color shall be continuous green for all equipment grounding conductors, except that wire sizes No. 4 AWG and larger shall be identified per NEC.

26 05 26 - 3

B. Bonding conductors shall be bare stranded copper, except that sizes No.

10 AWG and smaller shall be bare solid copper. Bonding conductors shall be stranded for final connection to motors, transformers, and vibrating equipment.

C. Conductor sizes shall not be less than shown on the drawings, or not less than required by the NEC, whichever is greater.

D. Insulation: THHN-THWN and XHHW-2. XHHW-2 shall be used for isolated power systems.

2.2 GROUND RODS

A. Steel or copper clad steel, 19 mm (0.75 inch) diameter by 3 M (10 feet) long.

B. Quantity of rods shall be as shown on the drawings, and as required to obtain the specified ground resistance.

2.3 CONCRETE ENCASED ELECTRODE

A. Concrete encased electrode shall be No. 4 AWG bare copper wire, installed per NEC.

2.4 GROUND CONNECTIONS

A. Below Grade and Inaccessible Locations: Exothermic-welded type connectors.

B. Above Grade:

1. Bonding Jumpers: Listed for use with aluminum and copper conductors.

For wire sizes No. 8 AWG and larger, use compression-type connectors. For wire sizes smaller than No. 8 AWG, use mechanical type lugs. Connectors or lugs shall use zinc-plated steel bolts, nuts, and washers. Bolts shall be torqued to the values recommended by the manufacturer.

2. Connection to Building Steel: Exothermic-welded type connectors.

3. Connection to Grounding Bus Bars: Listed for use with aluminum and copper conductors. Use mechanical type lugs, with zinc-plated steel bolts, nuts, and washers. Bolts shall be torqued to the values recommended by the manufacturer.

4. Connection to Equipment Rack and Cabinet Ground Bars: Listed for use with aluminum and copper conductors. Use mechanical type lugs, with zinc-plated steel bolts, nuts, and washers. Bolts shall be torqued to the values recommended by the manufacturer.

2.5 EQUIPMENT RACK AND CABINET GROUND BARS

A. Provide solid copper ground bars designed for mounting on the framework of open or cabinet-enclosed equipment racks. Ground bars shall have

26 05 26 - 4 minimum dimensions of 6.3 mm (0.25 inch) thick x 19 mm (0.75 inch) wide, with length as required or as shown on the drawings. Provide insulators and mounting brackets.

2.6 GROUND TERMINAL BLOCKS

A. At any equipment mounting location (e.g., backboards and hinged cover enclosures) where rack-type ground bars cannot be mounted, provide mechanical type lugs, with zinc-plated steel bolts, nuts, and washers.

Bolts shall be torqued to the values recommended by the manufacturer.

2.7 GROUNDING BUS BAR

A. Pre-drilled rectangular copper bar with stand-off insulators, minimum

6.3 mm (0.25 inch) thick x 100 mm (4 inches) high in cross-section, length as shown on the drawings, with hole size, quantity, and spacing per detail shown on the drawings. Provide insulators and mounting brackets.

PART 3 - EXECUTION

3.1 GENERAL

A. Installation shall be in accordance with the NEC, as shown on the drawings, and manufacturer’s instructions.

B. System Grounding:

1. Secondary service neutrals: Ground at the supply side of the secondary disconnecting means and at the related transformer.

2. Separately derived systems (transformers downstream from the service entrance): Ground the secondary neutral.

3. Isolation transformers and isolated power systems shall not be system grounded.

C. Equipment Grounding: Metallic piping, building structural steel, electrical enclosures, raceways, junction boxes, outlet boxes, cabinets, machine frames, and other conductive items in close proximity with electrical circuits, shall be bonded and grounded.

D. For patient care area electrical power system grounding, conform to the latest NFPA 70 and 99.

3.2 INACCESSIBLE GROUNDING CONNECTIONS

A. Make grounding connections, which are normally buried or otherwise inaccessible, by exothermic weld.

3.3 MEDIUM-VOLTAGE EQUIPMENT AND CIRCUITS

A. Switchgear: Provide a bare grounding electrode conductor from the switchgear ground bus to the grounding electrode system.

26 05 26 - 5

B. Duct Banks and Manholes: Provide an insulated equipment grounding conductor in each duct containing medium-voltage conductors, sized per

NEC except that minimum size shall be No. 2 AWG. Bond the equipment grounding conductors to the switchgear ground bus, to all manhole grounding provisions and hardware, to the cable shield grounding provisions of medium-voltage cable splices and terminations, and to equipment enclosures.

C. Lightning Arresters: Connect lightning arresters to the equipment ground bus or ground rods as applicable.

3.4 SECONDARY VOLTAGE EQUIPMENT AND CIRCUITS

A. Main Bonding Jumper: Bond the secondary service neutral to the ground bus in the service equipment.

B. Metallic Piping, Building Structural Steel, and Supplemental

Electrode(s):

1. Provide a grounding electrode conductor sized per NEC between the service equipment ground bus and all metallic water pipe systems, building structural steel, and supplemental or made electrodes.

Provide jumpers across insulating joints in the metallic piping.

2. Provide a supplemental ground electrode as shown on the drawings and bond to the grounding electrode system.

C. Switchgear, Switchboards, Unit Substations, Panelboards, Motor Control

Centers, Engine-Generators, Automatic Transfer Switches, and other electrical equipment:

1. Connect the equipment grounding conductors to the ground bus.

2. Connect metallic conduits by grounding bushings and equipment grounding conductor to the equipment ground bus.

D. Transformers:

1. Exterior: Exterior transformers supplying interior service equipment shall have the neutral grounded at the transformer secondary.

Provide a grounding electrode at the transformer.

2. Separately derived systems (transformers downstream from service equipment): Ground the secondary neutral at the transformer. Provide a grounding electrode conductor from the transformer to the nearest component of the grounding electrode system.

3.5 RACEWAY

A. Conduit Systems:

1. Ground all metallic conduit systems. All metallic conduit systems shall contain an equipment grounding conductor.

26 05 26 - 6

2. Non-metallic conduit systems, except non-metallic feeder conduits that carry a grounded conductor from exterior transformers to interior or building-mounted service entrance equipment, shall contain an equipment grounding conductor.

3. Metallic conduit that only contains a grounding conductor, and is provided for its mechanical protection, shall be bonded to that conductor at the entrance and exit from the conduit.

4. Metallic conduits which terminate without mechanical connection to an electrical equipment housing by means of locknut and bushings or adapters, shall be provided with grounding bushings. Connect bushings with a equipment grounding conductor to the equipment ground bus.

B. Feeders and Branch Circuits: Install equipment grounding conductors with all feeders, and power and lighting branch circuits.

C. Boxes, Cabinets, Enclosures, and Panelboards:

1. Bond the equipment grounding conductor to each pullbox, junction box, outlet box, device box, cabinets, and other enclosures through which the conductor passes (except for special grounding systems for intensive care units and other critical units shown).

2. Provide lugs in each box and enclosure for equipment grounding conductor termination.

D. Wireway Systems:

1. Bond the metallic structures of wireway to provide electrical continuity throughout the wireway system, by connecting a No. 6 AWG bonding jumper at all intermediate metallic enclosures and across all section junctions.

2. Install insulated No. 6 AWG bonding jumpers between the wireway system, bonded as required above, and the closest building ground at each end and approximately every 16 M (50 feet).

3. Use insulated No. 6 AWG bonding jumpers to ground or bond metallic wireway at each end for all intermediate metallic enclosures and across all section junctions.

4. Use insulated No. 6 AWG bonding jumpers to ground cable tray to column-mounted building ground plates (pads) at each end and approximately every 15 M (49 feet).

E. Receptacles shall not be grounded through their mounting screws. Ground receptacles with a jumper from the receptacle green ground terminal to

26 05 26 - 7 the device box ground screw and a jumper to the branch circuit equipment grounding conductor.

F. Ground lighting fixtures to the equipment grounding conductor of the wiring system. Fixtures connected with flexible conduit shall have a green ground wire included with the power wires from the fixture through the flexible conduit to the first outlet box.

G. Fixed electrical appliances and equipment shall be provided with a ground lug for termination of the equipment grounding conductor.

H. Raised Floors: Provide bonding for all raised floor components as shown on the drawings.

I. Panelboard Bonding in Patient Care Areas: The equipment grounding terminal buses of the normal and essential branch circuit panel boards serving the same individual patient vicinity shall be bonded together with an insulated continuous copper conductor not less than No. 10 AWG, installed in rigid metal conduit.

3.6 CORROSION INHIBITORS

A. When making grounding and bonding connections, apply a corrosion inhibitor to all contact surfaces. Use corrosion inhibitor appropriate for protecting a connection between the metals used.

3.7 CONDUCTIVE PIPING

A. Bond all conductive piping systems, interior and exterior, to the grounding electrode system. Bonding connections shall be made as close as practical to the equipment ground bus.

B. In operating rooms and at intensive care and coronary care type beds, bond the medical gas piping and medical vacuum piping at the outlets directly to the patient ground bus.

3.8 LIGHTNING PROTECTION SYSTEM

A. Bond the lightning protection system to the electrical grounding electrode system.

3.9 MAIN ELECTRICAL ROOM GROUNDING

A. Provide ground bus bar and mounting hardware at each main electrical room where incoming feeders are terminated, as shown on the drawings.

Connect to pigtail extensions of the building grounding ring, as shown

3.10 GROUND RESISTANCE

A. Grounding system resistance to ground shall not exceed 5 ohms. Make any modifications or additions to the grounding electrode system necessary

26 05 26 - 8 for compliance without additional cost to the Government. Final tests shall ensure that this requirement is met.

B. Grounding system resistance shall comply with the electric utility company ground resistance requirements.

3.11 GROUND ROD INSTALLATION

A. For outdoor installations, drive each rod vertically in the earth, until top of rod is 610 mm (24 inches) below final grade.

B. For indoor installations, leave 100 mm (4 inches) of each rod exposed.

C. Where buried or permanently concealed ground connections are required, make the connections by the exothermic process, to form solid metal joints. Make accessible ground connections with mechanical pressure-type ground connectors.

D. Where rock or impenetrable soil prevents the driving of vertical ground rods, install angled ground rods or grounding electrodes in horizontal trenches to achieve the specified ground resistance.

3.12 ACCEPTANCE CHECKS AND TESTS

A. Resistance of the grounding electrode system shall be measured using a four-terminal fall-of-potential method as defined in IEEE 81. Ground resistance measurements shall be made before the electrical distribution system is energized or connected to the electric utility company ground system, and shall be made in normally dry conditions not fewer than 48 hours after the last rainfall.

B. Resistance measurements of separate grounding electrode systems shall be made before the systems are bonded together. The combined resistance of separate systems may be used to meet the required resistance, but the specified number of electrodes must still be provided.

C. Below-grade connections shall be visually inspected by the COR// prior to backfilling. The Contractor shall notify the COR 24 hours before the connections are ready for inspection.

---END---

26 05 73 - 1

SECTION 26 05 73

OVERCURRENT PROTECTIVE DEVICE COORDINATION STUDY

A. This section specifies the overcurrent protective device coordination study, related calculations and analysis, indicated as the study in this section.

B. A short-circuit and selective coordination study, and arc flash calculations and analysis shall be prepared for the electrical overcurrent devices to be installed under this project.

C. The study shall present a well-coordinated time-current analysis of each overcurrent protective device from the individual device up to the utility source and the on-site generator sources.

D. Section 26 05 26, GROUNDING AND BONDING FOR ELECTRICAL SYSTEMS:

Requirements for personnel safety and to provide a low impedance path for possible ground fault currents.

E. Section 26 11 16, SECONDARY UNIT SUBSTATIONS.

B. The study shall be prepared by the equipment manufacturer, and performed by the equipment manufacturer’s licensed electrical engineer.

1.4 SUBMITTALS

1. Product data on the software program to be used for the study.

Software shall be in mainstream use in the industry, shall provide

26 05 73 - 2 device settings and ratings, and shall show selective coordination by time-current drawings.

2. Complete study as described in paragraph 1.6. Submittal of the study shall be well-coordinated with submittals of the shop drawings for equipment in related specification sections.

3. Certifications: Two weeks prior to final inspection, submit the following.

a. Certification by the Contractor that the overcurrent protective devices have been set in accordance with the approved study.

1.5 APPLICABLE PUBLICATIONS

B. Institute of Electrical and Electronics Engineers (IEEE):

241-90..................Recommended Practice Electrical Systems in

Commercial Buildings

242-03..................Recommended Practice for Protection and

Coordination of Industrial and Commercial Power

Systems

399-97..................Recommended Practice for Industrial and

Commercial Power Systems Analysis

1584-02.................Performing Arc-Flash Hazards Calculations

1584A-04................Performing Arc-Flash Hazards Calculations –

Amendment 1

1584B-11................Performing Arc-Flash Hazards Calculations –

Amendment 2

C. National Fire Protection Association (NFPA):

70E-18..................Standard for Electrical Safety in the Workplace

99-18...................Health Care Facilities Code

1.6 STUDY REQUIREMENTS

A. The study shall be in accordance with IEEE and NFPA standards.

B. The study shall include one line diagram, short-circuit and ground fault analysis, protective coordination plots for all overcurrent protective devices, and arc flash calculations and analysis.

C. One Line Diagram:

26 05 73 - 3

1. Show all electrical equipment and wiring to be protected by the overcurrent devices.

2. Show the following specific information:

a. Calculated fault impedance, X/R ratios, and short-circuit values at each feeder and branch circuit bus.

b. Relay, circuit breaker, and fuse ratings.

c. Generator kW/kVA and transformer kVA and voltage ratings, percent impedance, X/R ratios, and wiring connections.

d. Voltage at each bus.

e. Identification of each bus, matching the identification on the drawings.

f. Conduit, conductor, and busway material, size, length, and X/R ratios.

D. Short-Circuit Study:

1. The study shall be performed using computer software designed for this purpose. Pertinent data and the rationale employed in developing the calculations shall be described in the introductory remarks of the study.

2. Calculate the fault impedance to determine the available short-circuit and ground fault currents at each bus. Incorporate applicable motor and/or generator contribution in determining the momentary and interrupting ratings of the overcurrent protective devices.

3. Present the results of the short-circuit study in a table. Include the following:

a. Device identification.

b. Operating voltage.

c. Overcurrent protective device type and rating.

d. Calculated short-circuit current.

E. Coordination Study:

1. Prepare the coordination curves to determine the required settings of overcurrent protective devices to demonstrate selective coordination. Graphically illustrate on log-log paper that adequate time separation exists between devices, including the utility company upstream device if applicable. Plot the specific time-current characteristics of each overcurrent protective device in such a manner that all devices are clearly depicted.

26 05 73 - 4

2. The following specific information shall also be shown on the coordination curves:

b. Potential transformer and current transformer ratios.

c. Three-phase and single-phase ANSI damage points or curves for each cable, transformer, or generator.

d. Applicable circuit breaker or protective relay characteristic curves.

e. No-damage, melting, and clearing curves for fuses.

f. Transformer in-rush points.

3. Develop a table to summarize the settings selected for the overcurrent protective devices. Include the following in the table:

b. Protective relay or circuit breaker potential and current transformer ratios, sensor rating, and available and suggested pickup and delay settings for each available trip characteristic.

c. Fuse rating and type.

F. Arc Flash Calculations and Analysis:

1. Arc flash warning labels shall comply with Section 26 05 11, REQUIREMENTS FOR ELECTRICAL INSTALLATIONS.

2. Arc flash calculations shall be based on actual over-current protective device clearing time. Maximum clearing time shall be in accordance with IEEE 1584.

3. Arc flash analysis shall be based on the lowest clearing time setting of the over-current protective device to minimize the incident energy level without compromising selective coordination.

4. Arc flash boundary and available arc flash incident energy at the corresponding working distance shall be calculated for all electrical power distribution equipment specified in the project, and as shown on the drawings.

5. Required arc-rated clothing and other PPE shall be selected and specified in accordance with NFPA 70E.

1.7 ANALYSIS

A. Analyze the short-circuit calculations, and highlight any equipment determined to be underrated as specified. Propose solutions to effectively protect the underrated equipment.

26 05 73 - 5

1.8 ADJUSTMENTS, SETTINGS, AND MODIFICATIONS

A. Final field settings and minor modifications of the overcurrent protective devices shall be made to conform with the study, without additional cost to the Government.

PART 2 - PRODUCTS (NOT USED)

PART 3 - EXECUTION (NOT USED)

26 11 16 - 1

SECTION 26 11 16

SECONDARY UNIT SUBSTATIONS

testing of the secondary unit substations, referred to as substation(s) in this section.

E. Section 26 05 73, OVERCURRENT PROTECTIVE DEVICE COORDINATION STUDY:

1.4 FACTORY TESTS

A. Factory Tests shall be required.

B. Factory Tests shall be in accordance with Paragraph, MANUFACTURED

PRODUCTS in Section 26 05 11, REQUIREMENTS FOR ELECTRICAL

INSTALLATIONS, and the following requirement:

1. Substations shall be thoroughly tested at the factory to assure that there are no electrical or mechanical defects. Tests shall be conducted per UL and ANSI Standards. Factory tests shall be certified. The following tests shall be performed:

a. Transformer Section:

1) Perform insulation-resistance tests winding-to-winding and each winding-to-ground.

2) Perform turns-ratio tests at all tap positions.

26 11 16 - 2

1.5 SUBMITTALS

b. Prior to fabrication of substations, submit the following data for approval:

1) Complete electrical ratings, including primary and secondary voltage, decibel rating, temperature rise, nominal impedance, voltage regulation, and no load and full load losses.

2) Nameplate data.

3) Elementary and interconnection wiring diagrams.

4) Technical data for each component.

5) Dimensioned exterior views of the substations.

6) Dimensioned section views of the substations.

7) Floor plan of the substations.

8) Foundation plan for the substations.

9) Provisions and required locations for external conduit and wiring entrances.

10) Approximate design weights.

2. Manuals:

a. Submit, simultaneously with the shop drawings, complete maintenance and operating manuals, including technical data sheets, wiring diagrams, and information for ordering replacement parts.

1) Include three-line diagrams showing device terminal numbers.

2) Include schematic signal and control diagrams, with all terminals identified, matching terminal identification in the substation.

3) Include information for testing, repair, troubleshooting, assembly, and disassembly.

b. If changes have been made to the maintenance and operating manuals originally submitted, submit updated maintenance and operating manuals two weeks prior to the final inspection.

3. Test Reports:

26 11 16 - 3

a. Submit certified factory design and production test reports for approval.

b. Two weeks prior to the final inspection, submit certified field test reports.

4. Certifications: Two weeks prior to final inspection, submit the following:

a. Certification by the manufacturer that substations conform to the requirements of the drawings and specifications.

b. Certification by the Contractor that substations have been properly installed, adjusted, and tested.

1.6 APPLICABLE PUBLICATIONS

supplements, and errata), form a part of this specification to the extent referenced. Publications are referenced in the text by basic

B. American Concrete Institute (ACI):

ACI 318-14..............Building Code Requirements for Structural

Concrete.

C. American Society for Testing and Materials (ASTM):

D 117-10................Standard Guide for Sampling, Test Methods, and

Specifications for Electrical Insulating Oils of Petroleum Origin

D 3487-16...............Standard Specification for Mineral Insulating

Oil Used in Electrical Apparatus.

D. International Code Council (ICC):

IBC-15..................International Building Code

E. Institute of Electrical and Electronic Engineers (IEEE):

C37.121-12 .............Guide for Switchgear - Unit Substations —

Requirements

C57.12.00-15............General Requirements for Liquid-Immersed

Distribution, Power, and Regulating

Transformers

C57.12.01-15............General Requirements for Dry-Type Distribution and Power Transformers

C62.11-12...............Metal Oxide Surge Arresters for AC Power

Circuits (> 1kV)

C62.41-91...............Recommended Practice on Surge Voltage in Low

Voltage AC Power Circuits

26 11 16 - 4

F. National Electrical Manufacturers Association (NEMA):

TR 1-13.................Transformers, Step Voltage Regulators and

Reactors

G. National Fire Protection Association (NFPA):

H. United States Department of Energy

10 CFR Part 431.........Energy Efficiency Program for Certain

Commercial and Industrial Equipment

2.1 GENERAL REQUIREMENTS

A. Unless otherwise specified, substations shall be in accordance with

ANSI, ASTM, IEEE, NFPA, UL, 10 CFR Part 431, and as shown on the drawings.

B. Substations shall be a unitized integral assemblies, complete, grounded, continuous-duty, metal-clad, dead-front, dead-rear, with liquid-filled transformer.

C. Substations shall be designed, manufactured, and rated for indoor installation and service. External doors shall have provisions for padlocking.

D. Substation ratings shall be not less than required by the NEC, and not less than shown on the drawings. Short circuit current ratings shall be not less than the available maximum short circuit currents as shown

E. Substations shall conform to the arrangements and details shown on the drawings, and to the space designated for installation.

F. Substations shall be assembled and prewired by the manufacturer at the factory. Substations shall be sub-assembled and shipped in complete sections ready for connection at the site. Where practical, a substation shall be shipped as one unit.

H. Substations shall be thoroughly cleaned, phosphate treated, and painted at the factory with light gray rust-inhibiting paint or baked enamel.

2.2 MEDIUM-VOLTAGE SECTION

A. Interrupting ratings shall be not less than the maximum short circuit current available, as shown on the drawings.

2.3 LIQUID-FILLED TRANSFORMERS

A. Shall have the following features:

1. Self-cooled by natural convection, with isolated windings.

26 11 16 - 5

2. Auto-transformers will not be accepted.

3. Ratings indicated are for continuous-duty without the use of cooling fans.

4. Temperature rises shall not exceed the following NEMA Standard test values for the respective insulation systems: 65 degrees C (149 degrees F) by resistance and 80 degrees C (176 degrees F) hottest spot.

5. Transformer insulating liquid shall be:

a. Mineral oil: ASTM D 3487, Type II, tested in accordance with

ASTM D 117

6. Nominal impedance shall be as shown on the drawings, but not less than 4-1/2 percent.

7. Sound levels shall conform to 3 dB below the NEMA standards.

8. Primary and secondary windings:

a. Windings shall be copper.

b. Primary windings shall be delta-connected.

c. Secondary windings shall be wye-connected except where otherwise shown on the drawings.

d. Leads shall be brought out through wet process, porcelain bushings, pressure-tight.

e. Secondary windings shall have neutral bushings for transformers with wye-connected secondary windings.

f. Terminals shall be the most suitable clamp or blade type as required for the circuit connections.

9. Provide four, 2-1/2 percent full capacity taps in the primary windings, with two taps above rated voltage and two taps below rated voltage.

10. Core and Coil Assemblies:

a. Assemblies shall be rigidly braced to withstand the stresses caused by rough handling during shipment and the stresses caused by short circuit currents.

b. Cores shall be grain-oriented, non-aging, silicon steel.

c. Coils shall be continuous windings without splices except for taps.

d. Coil loss and core loss shall be optimized for efficient operation.

e. Primary, secondary, and tap connections shall be brazed or pressure type.

26 11 16 - 6

f. Coil windings shall have end fillers or tie downs.

11. Tanks, covers, and radiators shall be steel.

12. Features and accessories shall include the following:

a. Tap changer.

b. Lifting, pulling, and jacking provisions.

c. Globe type valves for filtering and draining.

d. Grounding pad.

e. Dial-type liquid thermometer with a maximum reading pointer and an external reset.

f. Liquid level gauge.

g. Pressure relief device.

h. Diagrammatic nameplate, including date of manufacture.

i. Auxiliary cooling equipment and controls.

1) Transformer shall be forced-air cooled. Forced-air cooling fans shall have cooling system controls, including thermal sensors, fans, control wiring, temperature controller with test switch, power panel with current-limiting fuses, indicating lights, alarm, and alarm silencing relay.

13. Transformer energy efficiency shall comply with the United States

Department of Energy’s 10 CFR Part 431.//

B. Transformer shall be rated 2,000kVA rating as shown on the drawings.

60kV BIL primary and 10 kV BIL secondary.

C. Primary and secondary windings:

1. Windings shall be copper.

2. Primary windings shall be delta-connected.

3. Secondary windings shall be wye-connected except where otherwise shown on the drawings.

4. Secondary windings shall have neutral bushings for transformers with wye-connected secondary windings.

5. Terminals shall be the most suitable clamp or blade type as required for the circuit connections.

D. Provide four 2-1/2 percent full capacity taps, two above and two below rated primary voltage. Locate tap adjustments on the face of the medium voltage coil. Adjustments shall be accessible by removing the front panel and shall be made when the transformer is de-energized.

E. Features and accessories shall include the following:

1. Winding temperature indicator.

2. Auxiliary cooling equipment and controls.

26 11 16 - 7

a. Transformer shall be forced-air-cooled. Forced-air-cooling fans shall have automatic temperature control relay and winding temperature indicator with sequence contacts.

F. Transformer energy efficiency shall comply with the United States

Department of Energy’s 10 CFR Part 431.

2.4 AUXILIARIES

A. Install additional components as shown on the drawings or otherwise required for the substations.

PART 3 – EXECUTION

3.1 INSTALLATION

A. Install substations in accordance with the NEC, as shown on the drawings, and as recommended by the manufacturer.

B. Coordinate the components of the substations and their arrangements electrically and mechanically. Coordinate all circuit entrances into the substations, including methods of entrance and connections.

C. Anchor substations with rustproof bolts, nuts, and washers not less than 13 mm (1/2 inch) diameter, in accordance with manufacturer’s instructions, and as shown on the drawings.

D. Interior Location. Mount substations on concrete slab. Unless otherwise indicated, the slab shall be at least 100 mm (4 inches) thick. The top of the concrete slab shall be approximately 100 mm (4 inches) above finished floor. Edges above floor shall have 15 mm (1/2 inch) chamfer. The slab shall be of adequate size to project at least

100 mm (8 inches) beyond the equipment. Provide conduit turnups and cable entrance space required by the equipment to be mounted. Seal voids around conduit openings in slab with water- and oil-resistant caulking or sealant. Cut off and bush conduits 75 mm (3 inches) above slab surface.

E. Substation Grounding:

1. Provide bare copper cable not smaller than No. 4/0 AWG, and not less than 610 mm (24 inches) below grade, interconnecting with the ground rods.

2. Surge arresters (if applicable) and neutral shall be bonded directly to the transformer enclosure, and then to the grounding electrode system with bare copper conductors, sized as shown on the drawings.

Lead lengths shall be kept as short as practical with no kinks or sharp bends.

26 11 16 - 8

3.2 ACCEPTANCE CHECKS AND TESTS

A. Perform tests in accordance with the manufacturer's recommendations.

In addition, include the following:

1. Medium-Voltage Section Tests:

a. Refer to Section 26 13 13, MEDIUM-VOLTAGE CIRCUIT BREAKER

SWITCHGEAR.

2. Transformer Inspection and Tests:

a. Compare equipment nameplate data with specifications and approved shop drawings.

b. Inspect physical and mechanical condition. Check for damaged or cracked insulators and liquid leaks.

c. Inspect all field-installed bolted electrical connections, verifying tightness of accessible bolted electrical connections by calibrated torque-wrench method, or performing thermographic survey after energization under load.

d. Verify correct liquid level in transformer tank.

e. Perform specific inspections and mechanical tests as recommended by manufacturer.

f. Verify correct equipment grounding.

g. Verify that the tap-changer is set at specified ratio.

h. Verify proper secondary voltage phase-to-phase and phase-to-neutral after energization and prior to loading.

3.3 FOLLOW-UP VERIFICATION

A. Upon completion of acceptance checks, settings, and tests, the

Contractor shall demonstrate that the substations are in good operating condition and properly performing the intended function.

3.4 TEMPORARY HEATING

A. Apply temporary heat to substations, according to manufacturer's written instructions, throughout periods when the environment is not controlled for temperature and humidity within manufacturer's stipulated service conditions.

3.5 ONE LINE DIAGRAM AND SEQUENCE OF OPERATION

A. At final inspection, an as-built one line diagram shall be laminated or mounted under acrylic glass, and installed in a frame mounted in the substation room or in the outdoor substation enclosure.

B. Furnish a written sequence of operation for the substation and connected line side/load side electrical distribution equipment. The sequence of operation shall be laminated or mounted under acrylic

26 11 16 - 9 glass, and installed in a frame mounted in the substation room or in the outdoor substation enclosure.

C. Deliver an additional four copies of the as-built one line diagram and sequence of operation to the COR.

3.6 INSTRUCTION

A. Furnish the services of a factory-trained technician for one 4-hour training period for instructing personnel in the maintenance and operation of the substations, on the dates requested by the COR.

26 12 19 - 1

SECTION 26 12 19

PAD-MOUNTED, LIQUID-FILLED, MEDIUM-VOLTAGE TRANSFORMERS

testing of the pad-mounted, liquid-filled, medium-voltage transformers, indicated as transformers in this section.

E. Section 26 05 73, OVERCURRENT PROTECTIVE DEVICE COORDINATION STUDY:

F. Section 26 11 16, SECONDARY UNIT SUBSTATIONS.

1.4 FACTORY TESTS

A. Factory Tests shall be required.

B. Factory Tests shall be in accordance with Paragraph, MANUFACTURED

PRODUCTS in Section 26 05 11, REQUIREMENTS FOR ELECTRICAL

INSTALLATIONS, and the following requirement:

1. Transformers shall be thoroughly tested at the factory to ensure that there are no electrical or mechanical defects. Tests shall be conducted as per IEEE Standards. Factory tests shall be certified.

The following tests shall be performed:

a. Perform insulation-resistance tests, winding-to-winding and each winding-to-ground.

b. Perform turns-ratio tests at all tap positions.

26 12 19 - 2

1.5 SUBMITTALS

b. Include electrical ratings, nameplate data, impedance, outline drawing with dimensions and front, top, and side views, weight, mounting details, decibel rating, termination information, temperature rise, no-load and full-load losses, regulation, overcurrent protection, connection diagrams, and accessories.

c. Complete nameplate data, including manufacturer’s name and catalog number.

2. Manuals:

a. When submitting the shop drawings, submit companion copies of complete maintenance and operating manuals, including technical data sheets, wiring diagrams, and information for ordering replacement parts.

1) Identify terminals on wiring diagrams to facilitate installation, maintenance, and operation.

2) Indicate on wiring diagrams the internal wiring for each piece of equipment and interconnections between the pieces of equipment.

3) Approvals will be based on complete submissions of manuals, together with shop drawings.

b. If changes have been made to the maintenance and operating manuals originally submitted, submit updated maintenance and operating manuals two weeks prior to the final inspection.

1) Update the manual to include any information necessitated by shop drawing approval.

2) Show all terminal identification.

3) Include information for testing, repair, troubleshooting, assembly, disassembly, and recommended maintenance intervals.

4) Provide a replacement parts list with current prices. Include a list of recommended spare parts, tools, and instruments for testing and maintenance purposes.

B. Certifications:

26 12 19 - 3

1. One day prior to the final inspection, submit the following certifications.

a. Certification by the manufacturer that the transformers conform to the requirements of the drawings and specifications.

b. Certification by the Contractor that the transformers have been properly installed, connected, and tested.

1.6 APPLICABLE PUBLICATIONS

B. American Society for Testing and Materials (ASTM):

D3487-16................Standard Specification for Mineral Insulating

Oil Used in Electrical Apparatus

C. Institute of Electrical and Electronic Engineers (IEEE):

48-09...................Test Procedures and Requirements for

Alternating-Current Cable Terminations Used on

Shielded Cables Having Laminated Insulation

Rated 2.5kV Through 765kV or Extruded

Insulation Rated 2.5kV Through 500kV

386-16..................Separable Insulated Connector Systems for Power

Distribution Systems Above 600 V

592-07..................Exposed Semiconducting Shields on High-Voltage

Cable Joints and Separable Connectors

C2-17...................National Electrical Safety Code

C37.47-11...............Specification for High Voltage (>1000V)

Distribution Class Current-Limiting Fuses and

Fuse Disconnecting Switches

C57.12.00-15............Liquid-Immersed Distribution, Power and

Regulating Transformers

C57.12.10-13............Liquid-Immersed Power Transformers

C57.12.25-90............Pad-Mounted, Compartmental-Type, Self-Cooled, Single-Phase Distribution-Transformers with

Separable Insulated High Voltage Connectors;

High Voltage, 34500 Grd Y/19920 Volts and

Below; Low-Voltage 240/120 Volts; 167 kVA and

Smaller Requirements

C57.12.28-14............Pad-Mounted Equipment - Enclosure Integrity

26 12 19 - 4

C57.12.29-14............Pad-Mounted Equipment – Enclosure Integrity for

Coastal Environments

C57.12.34-15............Pad-Mounted, Compartmental-Type, Self-Cooled, Three-Phase Distribution Transformers, 5 MVA and Smaller; High Voltage, 34.5 kV Nominal

System Voltage and Below; Low Voltage, 15kV

Nominal System Voltage and Below

C57.12.90-15............Test Code for Liquid-Immersed Distribution, Power, and Regulating Transformers

C62.11-12...............Metal-Oxide Surge Arresters for AC Power

Circuits

D. International Code Council (ICC):

IBC-15..................International Building Code

E. National Electrical Manufacturers Association (NEMA):

TR 1-13.................Transformers, Regulators, and Reactors

F. National Fire Protection Association (NFPA):

G. Underwriters Laboratories Inc. (UL):

467-13..................Grounding and Bonding Equipment

H. United States Department of Energy (DOE):

10 CFR Part 431.........Energy Efficiency Program for Certain

Commercial and Industrial Equipment

2.1 GENERAL REQUIREMENTS

A. Transformers shall be in accordance with ASTM, IEEE, NFPA, UL, as shown on the drawings, and as specified herein. Each transformer shall be assembled as an integral unit by a single manufacturer.

B. Transformers shall be complete, continuous duty, integral assembly, grounded, tamper-resistant, and with liquid-immersed windings.

C. Ratings shall not be less than shown on the drawings.

D. Completely fabricate transformers at the factory so that only the external cable connections are required at the project site.

E. All surfaces of the transformer that will be in contact with the concrete pad shall be treated with corrosion-resistant compounds and epoxy resin or a rubberized sealing compound.

2.2 COMPARTMENTS

A. Construction:

26 12 19 - 5

1. The medium- and low-voltage compartments shall be separated with a steel barrier that extends the full height and depth of the compartments.

2. The compartments shall be constructed of sheet steel (gauge to meet

ANSI requirements) with bracing and with reinforcing gussets using jig welds to assure rectangular rigidity.

3. All bolts, nuts, and washers shall be zinc-plated steel.

4. Sufficient space shall be provided for equipment, cabling, and terminations within the compartments.

5. Affix transformer nameplate permanently within the low-voltage compartment. Voltage and kVA rating, connection configuration, impedance, date of manufacture, and serial number shall be shown on the nameplate.

B. Doors:

1. Provide a separate door for each compartment with provisions for a single padlock to secure all doors. Provide each compartment door with open-position doorstops and corrosion-resistant tamperproof hinges welded in place. The medium-voltage compartment door shall be mechanically prevented from opening unless the low-voltage compartment door is open.

2. The secondary compartment door shall have a one-piece steel handle and incorporate three-point locking mechanisms.

2.3 BIL RATING

A. 5 kV class equipment shall have a minimum 60 kV BIL rating.

2.4 TRANSFORMER FUSE ASSEMBLY

A. The contractor shall field locate and verify transformer fuse assembly types.

2.5 PRIMARY CONNECTIONS

A. The contractor shall field locate and verify primary connection types.

2.6 MEDIUM-VOLTAGE SWITCH

A. The transformer primary disconnect switch shall be an oil-immersed, internal, gang-operated, load-interrupter type, rated at ampacity and system voltage as shown on the drawings, with a minimum momentary withstand rating of not less than the calculated available fault current shown on the drawings.

B. For radial feeds, switch shall be a two-position, on-off, manual switch located in the medium-voltage compartment and hot-stick-operated.

26 12 19 - 6

2.7 MEDIUM-VOLTAGE TERMINATIONS

A. The contractor shall field locate and verify all medium-voltage termination types.

B. Ground metallic cable shield with a cable shield grounding adapter, consisting of a solderless connector enclosed in watertight rubber housing covering the entire assembly, bleeder wire, and ground braid.

2.8 LOW-VOLTAGE EQUIPMENT

A. Mount the transformer secondary main molded case circuit breaker, low-voltage bushings, and hot stick in the low-voltage compartment.

B. The low-voltage leads shall be brought out of the tank by epoxy pressure tight bushings, and shall be standard arrangement.

C. Tin-plate the low-voltage neutral terminal and isolate from the transformer tank. Provide a removable ground strap sized in accordance with the NEC and connect between the secondary neutral and ground pad.

D. Mount the main breaker off of the transformer tank to allow sufficient ventilation and ensure that the heat from the transformer tank will not be transmitted through conduction. Circuit breakers shall be of the ambient compensating-type, with interrupting ratings for the available fault current.

2.9 TRANSFORMERS

A. Transformer ratings shall be as shown on drawings. kVA ratings shown on the drawings are for continuous duty without the use of cooling fans.

B. Temperature rises shall not exceed the NEMA TR 1 of 65˚ C (149˚ F) by resistance.

C. Transformer insulating material shall be mineral oil in accordance with

ASTM D 3487.

D. Transformer impedance shall be not less than 4-1/2% for sizes 150 kVA and larger. Impedance shall be as shown on the drawings.

E. Sound levels shall conform to NEMA TR 1 standards.

F. Primary and Secondary Windings for Three-Phase Transformers:

1. Primary windings shall be delta-connected.

2. Secondary windings shall be wye-connected, except where otherwise indicated on the drawings. Provide isolated neutral bushings for secondary wye-connected transformers.

3. Secondary leads shall be brought out through pressure-tight epoxy bushings.

G. Primary windings shall have four 2-1/2% full-capacity voltage taps; two taps above and two taps below rated voltage.

26 12 19 - 7

H. Core and Coil Assemblies:

1. Cores shall be grain-oriented, non-aging, silicon steel to minimize losses.

2. Core and coil assemblies shall be rigidly braced to withstand the stresses caused by rough handling during shipment, and stresses caused by any possible short-circuit currents.

3. Coils shall be continuous-winding type without splices except for taps. Material shall be copper.

4. Coil and core losses shall be optimum for efficient operation.

5. Primary, secondary, and tap connections shall be brazed or pressure type.

6. Provide end fillers or tie-downs for coil windings.

I. The transformer tank, cover, and radiator gauge thickness shall not be less than that required by ANSI.

J. Accessories:

1. Provide standard NEMA features, accessories, and the following:

a. No-load tap changer. Provide warning sign.

b. Lifting, pulling, and jacking facilities.

c. Globe-type valve for oil filtering and draining, including sampling device.

d. Pressure relief valve.

e. Liquid level gauge and filling plug.

f. A grounding pad in the medium- and low-voltage compartments.

g. A diagrammatic nameplate.

h. Dial-type liquid thermometer with a maximum reading pointer and an external reset.

i. Hot stick. Securely fasten hot stick within low-voltage compartment.

2. The accessories shall be made accessible within the compartments without disassembling trims and covers.

K. Transformers shall meet the energy conservation standards for transformer per the United States Department of Energy 10 CFR Part 431.

PART 3 - EXECUTION

3.1 INSTALLATION

A. Install transformer, as shown on the drawings, in accordance with the

NEC, and as recommended by the manufacturer.

B. Anchor transformers with zinc-platted bolts and as shown on drawings.

C. Mount transformer on existing concrete slab.

26 12 19 - 8

D. Grounding:

1. Ground each transformer in accordance with the requirements of the

NEC. Install ground rods per the requirements of Section 26 05 26, GROUNDING AND BONDING FOR ELECTRICAL SYSTEMS, to maintain a maximum resistance of 5 ohms to ground.

2. Connect the ground rod to the ground pads in the medium- and low-voltage compartments.

3. Install and connect the cable shield grounding adapter per the manufacturer’s instructions. Connect the bleeder wire of the cable shield grounding adapter to the loadbreak or deadbreak elbow grounding point with minimum No. 14 AWG wire, and connect the ground braid to the grounding system with minimum No. 6 AWG bare copper wire. Use soldered or mechanical grounding connectors listed for this purpose.

3.2 ACCEPTANCE CHECKS AND TESTS

A. Perform manufacturer’s required field tests in accordance with the manufacturer's recommendations. In addition, include the following:

1. Visual Inspection and Tests:

a. Compare equipment nameplate data with specifications and approved shop drawings.

b. Inspect physical and mechanical condition. Check for damaged or cracked bushings and liquid leaks.

c. Verify that control and alarm settings on temperature indicators are as specified.

d. Inspect all field-installed bolted electrical connections, using the calibrated torque-wrench method to verify tightness of accessible bolted electrical connections, and perform thermographic survey after energization under load.

e. Vacuum-clean transformer interior. Clean transformer enclosure exterior.

f. Verify correct liquid level in transformer tank.

g. Verify correct equipment grounding per the requirements of

Section 26 05 26, GROUNDING AND BONDING FOR ELECTRICAL SYSTEMS.

h. Verify the presence and connection of transformer surge arresters, if provided.

i. Verify that the tap-changer is set at rated system voltage.

26 12 19 - 9

3.3 FOLLOW-UP VERIFICATION

A. Upon completion of acceptance checks, settings, and tests, the

Contractor shall demonstrate that the transformers are in good operating condition and properly performing the intended function.

3.4 SPARE PARTS

A. Deliver the following spare parts for the project to the COR two weeks prior to final inspection:

1. Six insulated protective caps.

2. One spare set of medium-voltage fuses for each size and type of fuse used in the project.

3. One spare set of three cable fault indicators.

3.5 INSTRUCTION

A. The Contractor shall instruct maintenance personnel, for not less than one 2-hour period, on the maintenance and operation of the equipment on the date requested by the COR.

01 00 00 -1

SECTION 01 00 00

GENERAL REQUIREMENTS

1.1 SAFETY REQUIREMENTS

Refer to…