USACE / NAVFAC / AFCESA / NASA UFGS-26 12 19.00 40 (November 2008)
-----------------------------------
Preparing Activity: NASA Superseding
UFGS-26 12 00.00 40 (July 2007)
UNIFIED FACILITIES GUIDE SPECIFICATIONS
References are in agreement with UMRL dated January 2009
SECTION 26 12 19.00 40
PAD-MOUNTED, LIQUID-FILLED, MEDIUM-VOLTAGE TRANSFORMERS
11/08
NOTE: This guide specification covers three-phase pad-mounted transformers
of the dead-front and live-front types for exterior applications.
Use pad-mounted transformers (properly protected with bayonet type, oil-immersed,
expulsion fuses in series with oil-immersed, partial-range, current-limiting
fuses) for kVA ratings up to and including 750 kVA on 5 kV systems and for kVA
ratings up to and including 1500 kVA on 15 and 25 kV systems.
For voltages above 25 kV and in ratings above those previously indicated, this
specification requires significant modifications and additional specification
sections may need to be added on the project.
The use of pad-mounted transformers with secondary currents exceeding 2000 amperes
is discouraged due to the size and quantity of secondary conductors. Therefore,
transformers above 750 kVA serving 208Y/120 volt loads and transformers above
1500 kVA serving 480Y/277 volt loads should be in a secondary unit substation configuration.
Contact the cognizant EFD or PWC for direction.
For SOUTHNAVFACENGCOM projects, determine the use of secondary unit substations
on a case by case basis.
Use the following related guide specifications for power distribution equipment:
Section 26 08 00 APPARATUS INSPECTION AND TESTING
Section 26 12 19.20 SINGLE-PHASE PAD-MOUNTED TRANSFORMERS
Section 33 71 01 OVERHEAD TRANSMISSION AND DISTRIBUTION
Section 26 11 14.00 10 MAIN ELECTRIC SUPPLY STATION AND SUBSTATION
Section 26 11 13.00 20 PRIMARY UNIT SUBSTATION
Section 26 11 16 SECONDARY UNIT SUBSTATIONS
Section 26 28 00.00 10 MOTOR CONTROL CENTERS, SWITCHBOARDS AND PANELBOARDS
Section 26 22 00.00 10 480-VOLT STATION SERVICE SWITCHGEAR AND TRANSFORMERS
Section 26 23 00 SWITCHBOARDS AND SWITCHGEAR
Edit this guide specification for project specific requirements by adding, deleting,
or revising text. For bracketed items, choose applicable items(s) or insert
appropriate information.
Remove information and requirements not required in respective project, whether
or not brackets are present.
Comments and suggestion on this specification are welcome and should be directed
to the technical proponent of the specification. A listing of the technical
proponents, including their organization designation and telephone number, is
on the Internet.
Recommended changes to a UFGS should be submitted as a Criteria Change Request
(CCR).
NOTE: TO DOWNLOAD UFGS GRAPHICS
Go to http://www.wbdg.org/ccb/NAVGRAPH/graphtoc.pdf.
Do not include list of tables, or tables themselves, in project specifications.
Use tables to obtain values required in Part 2 of the specification.
For SOUTHNAVFACENGCOM facilities use Table PM-2.
TABLE NUMBER TITLE
PM-1 Transformer Loss & Impedance Data - for Energy
Cost (EC) Less Than or Equal to
$0.04 (2 pages)
PM-2 Transformer Loss & Impedance Data - for Energy
Cost (EC) Greater Than $0.04 and Less Than
or Equal to $0.08 (2 pages)
PM-3 Transformer Loss & Impedance Data - for Energy
Cost (EC) Greater Than $0.08 and Less Than
or Equal to $0.12 (2 pages)
EC-1 Energy costs at LANTNAVFACENGCOM Activities
(2 pages)
NOTE: Show the following information on the project drawings:
1. Single-line diagram showing pad-mounted transformer connectors, inserts,
surge arresters, switches, fuses, current transformers with ratings, and meters
as applicable.
2. Grounding plan.
3. Type and number of cables, and size of conductors for each power circuit.
4. Transformer primary and secondary voltages. (Use IEEE C57.12.00, Table
11(b), "Designation of voltage ratings of three-phase windings".) State the
primary voltage (nominal) actually in service and not the voltage class.
5. Special conditions, such as altitude, temperature and humidity; exposure
to fumes, vapors, dust, and gases; and seismic requirements.
PART 1 GENERAL
1.1 REFERENCES
The publications listed below form a part of this specification to the extent referenced. The publications are
referred to in the text by the basic designation only.
[ACI INTERNATIONAL (ACI)ACI 318M(2008) Metric Building Code Requirements for Structural Concrete and Commentary][AMERICAN NATIONAL STANDARDS INSTITUTE (ANSI)ANSI C12.7(2005) Requirements for Watthour Meter Sockets][ASTM INTERNATIONAL (ASTM)ASTM A 167(1999; R 2004) Standard Specification for Stainless and Heat-Resisting Chromium-Nickel Steel Plate, Sheet, and StripASTM C 260(2006) Standard Specification for Air-Entraining Admixtures for ConcreteASTM D 117(2002) Standard Guide for Sampling, Test Methods, Specifications and Guide for Electrical Insulating Oils of Petroleum OriginASTM D 1535(2008) Specifying Color by the Munsell SystemASTM D 3487(2008) Standard Specification for Mineral Insulating Oil Used in Electrical ApparatusASTM D 877(2002; R 2007) Standard Test Method for Dielectric Breakdown Voltage of Insulating Liquids Using Disk ElectrodesASTM D 92(2005a) Standard Test Method for Flash and Fire Points by Cleveland Open Cup TesterASTM D 97(2008) Pour Point of Petroleum Products][FM GLOBAL (FM)FM P7825(2005) Approval Guide][INSTITUTE OF ELECTRICAL AND ELECTRONICS ENGINEERS (IEEE)IEEE C2(2007; Errata 2007; INT 2008) National Electrical Safety CodeIEEE C37.47(1981) Distribution Fuse Disconnecting Switches, Fuse Supports, and Current-Limiting Fuses**IEEE C57.12.00(2006) Standard General Requirements for Liquid-Immersed Distribution, Power, and Regulating TransformersIEEE C57.12.25(1990) Standard for Transformers - Pad-Mounted, Compartmental-Type, Self-Cooled, Single-Phase Distribution Transformers with Separable Insulated High-Voltage Connectors; High Voltage (34 500-Grd Y/19 920 Volts and Below; Low Voltage, 240/120 Volts; 167 kVA and Smaller - Requirements)IEEE C57.12.28(2005) Standard for Pad-Mounted Equipment - Enclosure IntegrityIEEE C57.12.34(2004; Errata 2005) Pad-Mounted, Compartmental-Type, Self-Cooled, Three-Phase Distribution Transformers, 2500 kVA and Smaller—High-Voltage: 34 500 GrdY/19 920 Volts and Below; Low Voltage: 480 Volts and BelowIEEE C57.12.80(2002) Standard Terminology for Power and Distribution TransformersIEEE C57.12.90(2006) Standard Test Code for Liquid-Immersed Distribution, Power, and Regulating TransformersIEEE C57.13(2008) Standard Requirements for Instrument TransformersIEEE C57.98(1993; R 1999) Guide for Transformer Impulse TestsIEEE C62.11(2005; Amendment A 2008) Standard for Metal-Oxide Surge Arresters for Alternating Current Power Circuits (>1kV)IEEE Std 100(2000) The Authoritative Dictionary of IEEE Standards TermsIEEE Std 386(2006) Standard for Separable Insulated Connector Systems for Power Distribution Systems Above 600V][INTERNATIONAL ELECTRICAL TESTING ASSOCIATION (NETA)NETA ATS(2003) Acceptance Testing Specifications][NATIONAL ELECTRICAL MANUFACTURERS ASSOCIATION (NEMA)NEMA C12.1(2008) Electric Meters; Code for Electricity MeteringNEMA C12.10(2004) Physical Aspects of Watthour MetersNEMA LI 1(1998) Industrial Laminated Thermosetting Products][NATIONAL FIRE PROTECTION ASSOCIATION (NFPA)NFPA 70(2007; AMD 1 2008) National Electrical Code - 2008 Edition][ORGANISATION FOR ECONOMIC CO-OPERATION AND DEVELOPMENT (OECD)OECD Test 203(1992) Fish Acute Toxicity Test][U.S. ENVIRONMENTAL PROTECTION AGENCY (EPA)EPA 600/4-90/027F(1993) Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine OrganismsEPA 712-C-98-075(1996) Fate, Transport and Transformation Test Guidelines - OPPTS 835.3100- "Aerobic Aquatic Biodegradation"][UNDERWRITERS LABORATORIES (UL)UL 467(2007) Standard for Grounding and Bonding Equipment]1.2 RELATED REQUIREMENTS
NOTE: Include Section 26 08 00 APPARATUS INSPECTION AND TESTING on all projects
involving medium voltage and specialized power distribution equipment.
Section 26 08 00 APPARATUS INSPECTION AND TESTING applies to this section, with the additions and modifications
specified herein.
1.3 DEFINITIONS
a. Unless otherwise specified or indicated, electrical and electronics terms used in these specifications,
and on the drawings, shall be as defined in IEEE Std 100.
1.4 SUBMITTALS
NOTE: Submittals shall be limited to those necessary for adequate quality control.
The importance of an item in the project should be one of the primary factors
in determining if a submittal for the item should be required.
A “G” following a submittal item indicates that the submittal requires Government
approval. Some submittals are already marked with a “G”. Only delete an existing
“G” if the submittal item is not complex and can be reviewed through the Contractor’s
Quality Control system. Only add a “G” if the submittal is sufficiently important
or complex in context of the project.
For submittals requiring Government approval on Army projects, a code of up
to three characters within the submittal tags may be used following the "G"
designation to indicate the approving authority. Recommended codes for Army
projects are "RE" for Resident Engineer approval, "ED" for Engineering approval,
and "AE" for Architect-Engineer approval. Codes following the "G" typically
are not used for Navy projects.
Submittal items not designated with a "G" are considered as being for information
only for Army projects and for Contractor Quality Control approval for Navy
projects.
Government approval is required for submittals with a "G" designation; submittals not having a "G" designation
are for information only or as otherwise designated. When used, a designation following the "G" designation
identifies the office that will review the submittal for the Government. Submit the following in accordance
with Section 01 33 00 SUBMITTAL PROCEDURES:
NOTE: Include the bracketed option on "CIEE and 074 review" for NAVFAC Atlantic
and SOUTHNAVFACENGCOM projects respectively. For other projects, submittal
review shall be performed by the designer of record. If submittal review by
NAVFAC Atlantic or SOUTHNAVFACENGCOM is specifically desired, the responsible
Government agency must coordinate with the respective Code CIEE or 074 during
the design process. Add appropriate information in section entitled "Submittal
Procedures" to coordinate with the special requirements.
[[Code CIEE, NAVFAC Atlantic][Code 074, Southern Division, Naval Facilities Engineering Command] will review
and approve all submittals in this section requiring Government approval.] As an exception to this paragraph,
transformers manufactured by ABB in Jefferson City, MO; by Cooper Power Systems in Waukesha, WI; by ERMCO in
Dyersburg, TN; or by Howard Industries in Laurel, MS need not submit the entire submittal package requirements
of this contract. Instead, submit the following items:
a. A certification, from the manufacturer, that the technical requirements of this specification shall
be met.
b. An outline drawing of the transformer with devices identified (paragraph entitled "Pad-Mounted Transformer
Drawings", item a).
c. ANSI nameplate data of the transformer (paragraph entitled "Pad-Mounted Transformer Drawings", item
b).
NOTE: The designer is responsible for providing proper settings for any secondary
over-current device(s) to ensure proper protection of equipment and coordination
with transformer high side fuses. Include the following option for transformers
serving secondary over-current devices containing adjustable trips.
[d. Manufacturer's published time-current curves (on full size logarithmic paper) of the transformer
high side fuses (paragraph entitled "Pad-Mounted Transformer Drawings", item e).]
NOTE: Use "will" on all SOUTHNAVFACENGCOM projects. Coordinate with paragraph
entitled "Source Quality Control."
e. Routine and other tests (in PART 2, see paragraph entitled "Routine and Other Tests"), shall be conducted
by the manufacturer and [may][will] be witnessed by the government (in Part 2, see paragraph entitled
"Source Quality Control"). Provide transformer test schedule required by submittal item "SD-11 Closeout
Submittals". Provide certified copies of the tests.
f. Provide acceptance test reports required by submittal item "SD-06 Test Reports".
g. Provide operation and maintenance manuals required by submittal item "SD-10 Operation and Maintenance
Data".
SD-02 Shop Drawings
Pad-mounted transformer drawings[; G][; G, [_____]]
SD-03 Product Data
Pad-mounted transformers[; G][; G, [_____]]
Submittal shall include manufacturer's information for each component, device, and accessory
provided with the transformer.
SD-06 Test Reports
Acceptance checks and tests[; G][; G, [_____]]
SD-07 Certificates
Transformer losses[; G][; G, [_____]]
Submit certification from the manufacturer indicating conformance with the paragraph entitled
"Specified Transformer Losses."
SD-09 Manufacturer's Field Reports
Pad-mounted transformer design tests[; G][; G, [_____]]
Pad-mounted transformer routine and other tests[; G][; G, [_____]]
SD-10 Operation and Maintenance Data
Transformer(s), Data Package 5[; G][; G, [_____]]
Submit operation and maintenance data in accordance with Section 01 78 23 OPERATION AND MAINTENANCE
DATA and as specified herein.
SD-11 Closeout Submittals
Transformer test schedule[; G][; G, [_____]]
Submit report of test results as specified by paragraph entitled "Field Quality Control."
1.5 QUALITY ASSURANCE
1.5.1 Pad-Mounted Transformer Drawings
Drawings shall indicate, but not be limited to the following:
a. An outline drawing, with front, top, and side views.
b. ANSI nameplate data.
NOTE: Navy policy requires that all facilities be metered. If exception is
taken, coordinate with paragraphs entitled "Additions to Operation and Maintenance
Manuals" and "Metering."
c. Elementary diagrams and wiring diagrams with terminals identified of watthour meter and current transformers.
d. One-line diagram, including switch(es), current transformers, meters, and fuses.
e. Manufacturer's published time-current curves (on full size logarithmic paper) of the transformer
high side fuses.
1.5.2 Regulatory Requirements
In each of the publications referred to herein, consider the advisory provisions to be mandatory, as though the
word, "shall" had been substituted for "should" wherever it appears. Interpret references in these publications
to the "authority having jurisdiction," or words of similar meaning, to mean the Contracting Officer. Equipment,
materials, installation, and workmanship shall be in accordance with the mandatory and advisory provisions of
NFPA 70 unless more stringent requirements are specified or indicated.
1.5.3 Standard Products
Provide materials and equipment that are products of manufacturers regularly engaged in the production of such
products which are of equal material, design and workmanship. Products shall have been in satisfactory commercial
or industrial use for 2 years prior to bid opening. The 2-year period shall include applications of equipment
and materials under similar circumstances and of similar size. The product shall have been on sale on the commercial
market through advertisements, manufacturers' catalogs, or brochures during the 2-year period. Where two or
more items of the same class of equipment are required, these items shall be products of a single manufacturer;
however, the component parts of the item need not be the products of the same manufacturer unless stated in this
section.
1.5.3.1 Alternative Qualifications
Products having less than a 2-year field service record will be acceptable if a certified record of satisfactory
field operation for not less than 6000 hours, exclusive of the manufacturers' factory or laboratory tests, is
furnished.
1.5.3.2 Material and Equipment Manufacturing Date
Do not use products manufactured more than 3 years prior to date of delivery to site, unless specified otherwise.
1.6 MAINTENANCE
1.6.1 Additions to Operation and Maintenance Data
In addition to requirements of Data Package 5, include the following on the actual transformer(s) provided:
a. An instruction manual with pertinent items and information highlighted
b. An outline drawing, front, top, and side views
c. Prices for spare parts and supply list
d. Routine and field acceptance test reports
e. Fuse curves for primary fuses
f. Information on watthour demand meter, CT's, and fuse block
g. Actual nameplate diagram
h. Date of purchase
1.7 WARRANTY
The equipment items shall be supported by service organizations which are reasonably convenient to the equipment
installation in order to render satisfactory service to the equipment on a regular and emergency basis during
the warranty period of the contract.
PART 2 PRODUCTS
2.1 PRODUCT COORDINATION
Products and materials not considered to be pad-mounted transformers and related accessories are specified in[
Section 33 71 01 OVERHEAD TRANSMISSION AND DISTRIBUTION,][ Section 33 71 02.00 20 UNDERGROUND ELECTRICAL DISTRIBUTION,][
and][ Section 26 20 00 INTERIOR DISTRIBUTION SYSTEM][ Section 33 70 02.00 10 ELECTRICAL DISTRIBUTION SYSTEM,
UNDERGROUND].
2.2 THREE-PHASE PAD-MOUNTED TRANSFORMERS
NOTE: Use dead-front transformers unless available system fault current exceeds
equipment ratings. If live-front transformers are required, their use shall
be approved by the cognizant EFD.
IEEE C57.12.34, IEEE C57.12.28 and as specified herein.
2.2.1 Compartments
Separate the high- and low-voltage compartments with steel isolating barriers extending the full height and depth
of the compartments. Compartment doors: hinged lift-off type with stop in open position and three-point latching.
NOTE: Current policy is to use oil-immersed fuses in series with current limiting
fuses to achieve better protection and obtain life cycle cost benefits. Use
dry-well canister fuses only when specifically required by the activity.
Do not provide standoff bushings unless this transformer is the only dead-front
transformer on the base. Public works normally carries standoff bushings in
their vehicles. Provide protective caps when providing standoff bushings and
to cover unused bushing well inserts when not providing surge arresters.
2.2.1.1 High Voltage, Dead-Front
High-voltage compartment shall contain the incoming line, insulated high-voltage load-break connectors, bushing
well inserts,[ feed-thru inserts,] six high-voltage bushing wells configured for loop feed application, load-break
switch handle(s), access to [oil-immersed fuses][dry-well fuse canisters],[ dead-front surge arresters,] tap
changer handle, connector parking stands[ with insulated standoff bushings],[ protective caps,] and ground pad.
NOTE: The following paragraph is based on 200-ampere connectors. If transformer
primary load current is greater than 200 amperes or if primary cable size is
greater than No. 4/0 AWG, designer shall determine the appropriate connector system.
Portions of the 4.16 kV system at Dam Neck, VA and all of the 11.5 kV system
at Norfolk Naval Shipyard, VA have a fault capability in excess of 10,000 amps.
Locating the current-limiting fuses ahead of the load-break switch as specified
in this paragraph will limit the available fault current to less than 10,000
amps. Therefore, 600 amp separable insulated connectors with a short time rating
of 25,000 rms symmetrical amperes and load-break switches can be used on pad-mounted
transformers in these locations.
a. Insulated high-voltage load-break connectors: IEEE Std 386, rated [15][_____] kV, [95][_____] kV
BIL. Current rating: 200 amperes rms continuous. Short time rating: 10,000 amperes rms symmetrical
for a time duration of 0.17 seconds. Connector shall have a steel reinforced hook-stick eye, grounding
eye, test point, and arc-quenching contact material.
b. Bushing well inserts[ and feed-thru inserts]: IEEE Std 386, 200 amperes, [15][_____] kV Class.
Provide a bushing well insert for each bushing well unless indicated otherwise.[ Provide feed-thru inserts
as indicated.]
c. Load-break switch
NOTE: Choose one of the following options.
[Radial-feed oil-immersed type rated at [15][_____] kV, [95][_____] kV BIL, with a continuous current
rating and load-break rating of [200][_____] amperes, and a make-and-latch rating of 10,000 rms amperes
symmetrical. Locate the switch handle in the high-voltage compartment.]
[Loop feed sectionalizer switches: Provide three, two-position, oil-immersed type switches to permit
closed transition loop feed and sectionalizing. Each switch shall be rated at [15][_____] kV, [95][_____]
kV BIL, with a continuous current rating and load-break rating of [200][_____] amperes, and a make-and-latch
rating of 10,000 rms amperes symmetrical. Locate the switch handles in the high-voltage compartment.
Operation of switches shall be as follows:
| DESCRIPTION | SWITCH POSITION
ARRANGE- | OF SWITCH | LINE A SW. | LINE B SW | XFMR. SW
MENT NO. | ARRANGEMENT | OPEN|CLOSE | OPEN|CLOSE| OPEN|CLOSE
--------------------------------------------------------------------------
1 | Line A | | X | | X | | X
| connected | | | | | |
| to Line B | | | | | |
| and both lines | | | | | |
| connected to | | | | | |
| transformer | | | | | |
--------------------------------------------------------------------------
2 | Transformer | | X | X | | | X
| connected to | | | | | |
| Line A only | | | | | |
--------------------------------------------------------------------------
3 | Transformer | X | | | X | | X
| connected to | | | | | |
| Line B only | | | | | |
--------------------------------------------------------------------------
4 | Transformer | | X | | X | X |
| open and | | | | | |
| loop closed | | | | | |
--------------------------------------------------------------------------
5 | Transformer | X | | X | | X |
| open and | | | | | |
| loop open | | | | | |
-------------------------------------------------------------------------]
d. Provide bayonet type, oil-immersed, expulsion fuses in series with oil-immersed, partial-range, current-limiting
fuses. Bayonet fuse links shall sense both high currents and high oil temperature in order to provide
thermal protection to the transformer. Coordinate transformer protection with expulsion fuse clearing
low-current faults and current-limiting fuse clearing high-current faults beyond the interrupting rating
of the expulsion fuse. In order to eliminate or minimize oil spills, the bayonet fuse assembly shall
include an oil retention valve inside the housing which closes when the fuse holder is removed and an
external drip shield. Conspicuously display warning within the high-voltage compartment cautioning against
removing or inserting fuses unless the load-break switch is in the open position and the tank pressure
has been released.
Bayonet fuse assembly: 150 kV BIL.
NOTE: For transformers with loop-feed sectionalizer switching, delete the bracketed
option regarding placement of current-limiting fuses.
Oil-immersed current-limiting fuses: IEEE C37.47; 50,000 rms amperes symmetrical interrupting rating
at the system voltage specified.[ Connect current-limiting fuses ahead of the radial-feed load-break
switch.]
NOTE: When dry-well canisters are selected, delete the above paragraphs on
oil-immersed fuses.
[e. Current-limiting fuses, dry-well mount: IEEE C37.47. Provide fuses in air-insulated, oil-sealed,
dead-front, non-load-break dry-well fuse canisters, on the load side of the load-break switch serving
the transformer. Interlock fuse canisters with the load-break switch so that the fuses may be removed
and inserted only when the switch is in the "Off" position. Fuses shall remove the transformer from
service in case of an internal fault. Size fuses to approximately 150 percent of the transformer primary
full load current rating and in accordance with fuse manufacturer's recommendations for dry-well mounting.
Fuses shall have an interrupting rating of 50,000 rms amperes symmetrical at the system voltage specified.
Furnish a spare fuse for each fuse provided.]
[f. Surge arresters: IEEE C62.11, rated [3][6][9][10][12][15][_____] kV, fully shielded, dead-front,
metal-oxide-varistor, elbow type with resistance-graded gap, suitable for plugging into inserts.[ Provide
three arresters for radial feed circuits.][ Provide [three][six] arresters for loop feed circuits.]]
g. Parking stands: Provide a parking stand near each bushing well.[ Provide insulated standoff bushings
for parking of energized load-break connectors on parking stands.]
[h. Protective caps: IEEE Std 386, 200 amperes, [15][25][_____] kV Class. Provide insulated protective
caps (not shipping caps) for insulating and sealing out moisture from unused bushing well inserts[ and
insulated standoff bushings].]
[2.2.1.2 High Voltage, Live-Front
NOTE: When live-front is selected, delete the above paragraphs on dead-front.
High-voltage compartment shall contain the incoming line, transformer high-voltage bushings, load-break switch
handle(s), access to [oil-immersed fuses][dry-well fuse canisters],[ surge arresters,] tap changer handle, insulated
phase barriers, and ground pad.
a. Cable terminators: Provide as specified in Section[ 33 71 02.00 20 UNDERGROUND ELECTRICAL DISTRIBUTION][
33 70 02.00 10 ELECTRICAL DISTRIBUTION SYSTEM, UNDERGROUND].
b. Load-break switch
NOTE: Choose one of the following options.
[Radial-feed oil-immersed type rated at [15][_____] kV, [95][_____] kV BIL, with a continuous current
rating and load-break rating of [200][_____] amperes, and a make-and-latch rating of 10,000 rms amperes
symmetrical. Locate the switch handle in the high-voltage compartment.]
[Loop feed sectionalizer switches: Provide three, two-position, oil-immersed type switches to permit
closed transition loop feed and sectionalizing. Rate each switch at [15][_____] kV, [95][_____] kV BIL,
with a continuous current rating and load-break rating of [200][_____] amperes, and a make-and-latch
rating of 10,000 rms amperes symmetrical. Locate the switch handles in the high-voltage compartment.
Operation of switches shall be as follows:
| DESCRIPTION | SWITCH POSITION
ARRANGE- | OF SWITCH | LINE A SW. | LINE B SW | XFMR. SW
MENT NO. | ARRANGEMENT | OPEN|CLOSE | OPEN|CLOSE| OPEN|CLOSE
--------------------------------------------------------------------------
1 | Line A | | X | | X | | X
| connected | | | | | |
| to Line B and | | | | | |
| both lines | | | | | |
| connected to | | | | | |
| transformer | | | | | |
--------------------------------------------------------------------------
2 | Transformer | | X | X | | | X
| connected to | | | | | |
| Line A only | | | | | |
--------------------------------------------------------------------------
3 | Transformer | X | | | X | | X
connected to | | | | | |
| Line B only | | | | | |
--------------------------------------------------------------------------
4 | Transformer | | X | | X | X |
open and | | | | | |
| loop closed | | | | | |
--------------------------------------------------------------------------
5 | Transformer | X | | X | | X |
open and | | | | | |
| loop open | | | | | |
-------------------------------------------------------------------------]
c. Provide bayonet type, oil-immersed, expulsion fuses in series with oil-immersed, partial-range, current-limiting
fuses. Bayonet fuse links shall sense both high currents and high oil temperature in order to provide
thermal protection to the transformer. Coordinate transformer protection with expulsion fuse clearing
low-current faults and current-limiting fuse clearing high-current faults beyond the interrupting rating
of the expulsion fuse. In order to eliminate or minimize oil spills, the bayonet fuse assembly shall
include an oil retention valve inside the housing which closes when the fuse holder is removed and an
external drip shield. Conspicuously display warning within the high-voltage compartment cautioning against
removing or inserting fuses unless the load-break switch is in the open position and the tank pressure
has been released.
Bayonet fuse assembly: 150 kV BIL.
NOTE: For transformers with loop-feed sectionalizer switching, delete the bracketed
option regarding placement of current-limiting fuses.
Oil-immersed current-limiting fuses: IEEE C37.47; 50,000 rms amperes symmetrical interrupting rating
at the system voltage specified.[ Connect current-limiting fuses ahead of the radial-feed load-break
switch.]
NOTE: When dry-well canisters are selected, delete the above paragraphs on
oil-immersed fuses.
[d. Current-limiting fuses, dry-well mount: IEEE C37.47. Provide fuses in air-insulated, oil-sealed,
dead-front, non-load-break dry-well fuse canisters, on the load side of the load-break switch serving
the transformer. Interlock fuse canisters with the load-break switch so that the fuses may be removed
and inserted only when the switch is in the "Off" position. Fuses shall remove the transformer from
service in case of an internal fault. Size fuses to approximately 150 percent of the transformer primary
full load current rating and in accordance with fuse manufacturer's recommendations for dry-well mounting.
Fuses shall have an interrupting rating of 50,000 rms amperes symmetrical at the system voltage specified.
Furnish a spare fuse for each fuse provided.]
[e. Surge arresters: IEEE C62.11, rated [3][6][9][10][12][15][_____] kV.[ Provide three arresters
for radial feed circuits.][ Provide [three][six] arresters for loop feed circuits.]]
f. Insulated phase barriers: NEMA LI 1, Type GPO-3, 6.35 mm 0.25 inch minimum thickness. Provide vertical
barriers between the high-voltage bushings and a single horizontal barrier above the high-voltage bushings.
]2.2.1.3 Low Voltage
NOTE: Installation of circuit breakers in the secondary compartment is not
recognized by ANSI standards, and limits accessibility by covering lugs, gages,
and accessories. Do not use.
Low-voltage compartment shall contain low-voltage bushings with NEMA spade terminals, accessories,[ metering,]
stainless steel or laser-etched anodized aluminum diagrammatic transformer nameplate, and ground pad.
a. Accessories shall include drain valve with sampler device, fill plug, pressure relief device, liquid
level gage, pressure-vacuum gage, and dial type thermometer with maximum temperature indicator.
2.2.1.4 Three-Phase Metering
NOTE: When Section 23 09 23.13 20 BACnet DIRECT DIGITAL CONTROL SYSTEMS FOR
HVAC or Section 23 09 23 DIRECT DIGITAL CONTROL FOR HVAC AND OTHER LOCAL BUILDING
SYSTEMS is used, coordinate meter requirements. Form 9S, in text below, is
for three-phase, four-wire wye systems, for other system configurations, designer
shall determine the appropriate form designation.
1. Design: Provide meter designed for use on a 3-phase, 4-wire, [208Y/120][480Y/277] volt
system with 3 current transformers. Include necessary KYZ pulse initiation hardware for Energy
Monitoring and Control System (EMCS)[ as specified in Section[ 23 09 23 DIRECT DIGITAL CONTROL
HVAC AND OTHER LOCAL BUILDING SYSTEMS]].
2. Coordination: Provide meter coordinated with ratios of current transformers and transformer
secondary voltage.
3. Class: 20; Form: [9S][___]; Accuracy: +/- 1.0 percent; Finish: Class II
4. Cover: Polycarbonate and lockable to prevent tampering and unauthorized removal.
5. Kilowatt-hour Register: 5 digit electronic programmable type
6. Demand Register:
(a) Provide solid state
(b) Meter reading multiplier:
(1) Indicate multiplier on the meter face.
(c) Demand interval length: shall be programmed for [15][30][60] minutes with rolling demand
up to six subintervals per interval.
7. Meter fusing: Provide a fuse block mounted in the secondary compartment containing one
fuse per phase to protect the voltage input to the watthour meter. Size fuses as recommended
by the meter manufacturer.
8. Socket: ANSI C12.7. Provide NEMA Type 3R, box-mounted socket having automatic circuit-closing
bypass and having jaws compatible with requirements of the meter. Cover unused hub openings
with blank hub plates. Paint box Munsell 7GY3.29/1.5 green to match the pad-mounted transformer
to which the box-mounted socket is attached. The Munsell color notation is specified in ASTM D 1535
.
9. Current transformers: IEEE C57.13. Provide butyl-molded window type current transformers
with 600-volt insulation, 10 kV BIL and mount on the low-voltage bushings. Route current transformer
leads in a location as remote as possible from the power transformer secondary cables to permit
current measurements to be taken with hook-on-ammeters. Provide three current transformers
per power transformer with characteristics listed in the following table.
[1. NEMA C12.10. Metering for two-compartment transformers: Provide a socket-mounted electronic
programmable outdoor watthour meter, surface mounted flush against the side of the low-voltage
compartment as indicated. Meter shall either be programmed at the factory or programmed in
the field. When field programming is performed, turn field programming device over to the Contracting
Officer at completion of project. Coordinate meter to system requirements.
NOTE: When Section 23 09 23.13 20 BACnet DIRECT DIGITAL CONTROL SYSTEMS FOR
HVAC is used, coordinate meter requirements. Form 4S, in text below, is for
single-phase, three-wire systems, for other system configurations, designer
shall determine the appropriate form designation.
(a) Design: Provide meter designed for use on a single-phase, three-wire, [240/120][480/240]
volt system with two current transformers. Include necessary KYZ pulse initiation hardware
for energy monitoring and control system (EMCS)[ as specified in Section 23 09 23 DIRECT DIGITAL
CONTROL FOR HVAC AND OTHER BUILDING SYSTEMS].
(b) Coordination: Provide meter coordinated with ratios of current transformers and transformer
secondary voltage.
(c) Class: 20
Form: 4S, accuracy: plus or minus 1.0 percent
Finish: Class II
(d) Cover: Polycarbonate and lockable to prevent tampering and unauthorized removal.
(e) Kilowatt-hour register: Five digit electronic programmable type
(f) Demand register
(1) Provide solid state
(2) Meter reading multiplier: Indicate multiplier on the meter face.
(3) Demand interval length: Program for [15][30][60] minutes with rolling demand up to
six subintervals per interval.
(g) Meter fusing: Provide a fuse block mounted in the secondary side containing one fuse per
phase to protect the voltage input to the meter. Size fuses as recommended by the meter manufacturer.
(h) Socket: ANSI C12.7. Provide NEMA Type 3R, box-mounted socket having automatic circuit-closing
bypass and having jaws compatible with requirements of the meter. Cover unused hub openings
with blank hub plates. Paint box Munsell 7GY3.29/1.5 green to match the pad-mounted transformer
to which the box-mounted socket is attached. The Munsell color notation is specified in ASTM D 1535
.]
NOTE: The following guidelines for specifying current transformers are based
on the standard current transformer primary rating which is just below the full
load current of the power transformer.
1. Select the appropriate current transformer (CT) ratio, continuous-thermal-current
rating factor (RF) at 30 degrees C and ANSI Metering Accuracy Class values based
on transformer kVA size and secondary voltage. Example: for a 500 kVA transformer
at 208 volts - select 1200/5, 1.5, 0.3 - B-0.5.
|---------------------------(VOLTS)---------------------------|
| 208 | 240 |
|------------------------------|------------------------------|
| CT | | Meter | CT | | Meter |
kVA | Ratio | RF | Class | Ratio | RF | Class |
|------|------------------------------|------------------------------|
| 75 | 200/5, 4.0, 0.3 thru B-0.1 | 200/5, 4.0, 0.3 thru B-0.1 |
|112.5 | 300/5, 3.0, 0.3 thru B-0.2 | 200/5, 4.0, 0.3 thru B-0.1 |
| 150 | 400/5, 4.0, 0.3 thru B-0.2 | 300/5, 3.0, 0.3 thru B-0.2 |
| 225 | 600/5, 3.0, 0.3 thru B-0.5 | 400/5, 4.0, 0.3 thru B-0.2 |
| 300 | 800/5, 2.0, 0.3 thru B-0.5 | 600/5, 3.0, 0.3 thru B-0.5 |
| 500 | 1200/5, 1.5, 0.3 thru B-0.5 | 1200/5, 1.5, 0.3 thru B-0.5 |
| 750 | 2000/5, 1.5, 0.3 thru B-1.8 | 1500/5, 1.5, 0.3 thru B-0.9 |
--------------------------------------------------------------------
|---------------------------(VOLTS)--------------------------|
| 480 | 600 |
|------------------------------|-----------------------------|
| CT | | Meter | CT | | Meter |
kVA | Ratio | RF | Class | Ratio | RF | Class |
|------|------------------------------|-----------------------------|
| 75 | 200/5, 4.0, 0.3 thru B-0.1 | 200/5, 4.0, 0.3 thru B-0.1 |
|112.5 | 200/5, 4.0, 0.3 thru B-0.1 | 200/5, 4.0, 0.3 thru B-0.1 |
| 150 | 200/5, 4.0, 0.3 thru B-0.1 | 200/5, 4.0, 0.3 thru B-0.1 |
| 225 | 200/5, 4.0, 0.3 thru B-0.1 | 200/5, 4.0, 0.3 thru B-0.1 |
| 300 | 300/5, 3.0, 0.3 thru B-0.2 | 200/5, 4.0, 0.3 thru B-0.1 |
| 500 | 600/5, 3.0, 0.3 thru B-0.5 | 400/5, 4.0, 0.3 thru B-0.2 |
| 750 | 800/5, 2.0, 0.3 thru B-0.5 | 600/5, 3.0, 0.3 thru B-0.5 |
| 1000 | 1200/5, 1.5, 0.3 thru B-0.5 | 800/5, 2.0, 0.3 thru B-0.5 |
| 1500 | 1500/5, 1.5, 0.3 thru B-0.9 | 1200/5, 1.5, 0.3 thru B-0.5 |
| 2000 | 2000/5, 1.5, 0.3 thru B-1.8 | 1500/5, 1.5, 0.3 thru B-0.9 |
| 2500 | 3000/5, 1.33, 0.3 thru B-1.8 | 2000/5, 1.5, 0.3 thru B-1.8 |
-------------------------------------------------------------------
2. Incorporate the appropriate values in table below.
2.2.2 Compartment Construction
[a. Single compartment: Shall be Type 1 as defined by IEEE C57.12.25 with combination high- and low-voltage
compartment. Compartment shall be of the clam shell type with lockable (having pad-locking provisions)
hinged cover and single-point latching.]
[b. Two compartment: Separate the high- and low-voltage compartments with steel isolating barriers
extending the full height and depth of the compartments. Compartment doors: hinged lift-off type with
stop in open position and three-point latching.]
2.2.3 Transformer
NOTE: Use the following guidelines for specifying transformers.
1. Previously the use of mineral oil filled transformers were recommended wherever
possible. The recent availability of biodegradable less-flammable transformer
liquids may have altered that recommendation. For NAVFAC Atlantic , choose
less-flammable transformer liquids as specified below for all projects unless
there is a specific requirement to do otherwise. Where adequate distance from
structures cannot be attained, consult NAVFAC design manuals and UFC 3-600-01,
"Design: Fire Protection Engineering For Facilities." Do not use Silicon-filled
and R-temp filled transformers for less-flammable requirements.
2. Use IEEE C57.12.00, Table 11(b), voltage designations, such as "4160 V -
480Y / 277 V".
3. Select impedance value in accordance with technical note under paragraph
entitled "Specified Transformer Losses."
4. Delete inapplicable sound levels.
5. Delete last sentence if transformer secondary winding is delta type.
a. [Oil-insulated][Less-flammable liquid-insulated], two winding, 60 hertz, 65 degrees C rise above
a 30 degrees C average ambient, self-cooled type.
b. Transformer shall be rated [_____] kVA, [95][60][_____] kV BIL.
c. Transformer voltage ratings: [_____] V - [_____] V.[ For GrdY - GrdY transformers, provide transformer
with five-legged core design for third harmonic suppression.]
d. Tap changer shall be externally operated, manual type for changing tap setting when the transformer
is de-energized. Provide four 2.5 percent full capacity taps, two above and two below rated primary
voltage. Tap changers shall clearly indicate which tap setting is in use.
e. Minimum tested impedance shall not be less than [_____] percent at 85 degrees C on Three-Phase tranformers
[and [_____] at 85 degrees C on Single-Phase traformers].
f. Audible sound levels shall comply with the following:
kVA DECIBELS (MAX)
75 51
112.5 55
150 55
225 55
300 55
500 56
750 57
1000 58
1500 60
g. Transformer shall include lifting lugs and provisions for jacking under base. The transformer base
construction shall be suitable for using rollers or skidding in any direction. Provide transformer top
with an access handhole.[ Transformer shall have its kVA rating conspicuously displayed on its enclosure.]
The transformer shall have an insulated low-voltage neutral bushing with NEMA spade terminal, and with
removable ground strap.
2.2.3.1 Specified Transformer Losses
NOTE: Steps to specifying transformer losses.
1. Print Tables PM-1, PM-2, PM-3, and EC-1 as applicable (directions included
at the front of this specification).
2. Obtain energy cost for the specific activity from the cognizant EFD or PWC.
Energy costs should be based on the cost of energy without the demand charge
factors scaled in. Use Table EC-1 for energy costs at the NAVFAC Atlantic activities
indicated. Use Table PM-2 for energy costs at all SOUTHNAVFACENGCOM activities.
(Additional tables will be added for other EFD's as the information becomes
available.)
3. Use Tables PM-1, PM-2, and PM-3 to specify losses and impedances for transformers
based on energy cost range, and transformer primary and secondary voltages.
4. Perform fault current calculations to verify that distribution equipment
is coordinated with impedance specified.
[No-load losses (NLL) shall be [_____] watts at 20 degrees C and load losses (LL) shall be [_____] watts at 85
degrees C. Use the values for the specified losses for comparison with the losses determined during the routine
tests. If the routine test values for no-load losses exceed the specified no-load losses by more than 10 percent,
or the total losses exceed the specified total losses (sum of no-load and load losses) by more than 6 percent,
the transformer is unacceptable.]
2.2.4 Insulating Liquid
NOTE: Choose one of the following options. For NAVFAC Atlantic , choose less-flammable
transformer liquids for all projects unless there is a specific requirement
to do otherwise.
[a. Mineral oil: ASTM D 3487, Type II, tested in accordance with ASTM D 117. Provide identification
of transformer as "non-PCB" and "Type II mineral oil" on the nameplate.]
[b. Less-flammable transformer liquids: NFPA 70 and FM P7825 for less-flammable liquids having a fire
point not less than 300 degrees C tested per ASTM D 92 and a dielectric strength not less than 33 kV
tested per ASTM D 877. Provide identification of transformer as "non-PCB" and "manufacturer's name and
type of fluid" on the nameplate.
The fluid shall be a biodegradable electrical insulating and cooling liquid classified by UL and approved
by FM as "less flammable" fluids. The fluid shall meet the following fluid properties:
1. Pour point: ASTM D 97, less than -15 degree C
2. Aquatic biodegradation: EPA 712-C-98-075, 100%
3. Trout toxicity: OECD Test 203, zero mortality of EPA 600/4-90/027F, pass]
2.2.4.1 Liquid-Filled Transformer Nameplates
Provide distribution transformers with nameplate information in accordance with IEEE C57.12.00 and as modified
or supplemented by this section.
2.2.5 Corrosion Protection
NOTE: Use stainless steel bases and cabinets for most applications. In hostile
environments, the additional cost of totally stainless steel tanks and metering
may be justified. Manufacturer's standard construction material is acceptable
only in noncoastal and noncorrosive environments. Choose the second bracketed
option for hostile environments.
[Bases and cabinets of transformers shall be corrosion resistant and shall be fabricated of stainless steel conforming
to ASTM A 167, Type 304 or 304L. Base shall include any part of pad-mounted transformer that is within75 mm
3 inches of concrete pad. Paint bases, cabinets, and tanks Munsell 7GY3.29/1.5 green. Paint coating system
shall comply with IEEE C57.12.28. The Munsell color notation is specified in ASTM D 1535.][Entire transformer
assembly, including tank and radiator, base, enclosure, and metering enclosure shall be fabricated of stainless
steel conforming to ASTM A 167, Type 304 or 304L. Form enclosure of stainless steel sheets. Paint entire transformer
assembly Munsell 7GY3.29/1.5 green. Paint coating system shall comply with IEEE C57.12.28. The Munsell color
notation is specified in ASTM D 1535.]
2.3 WARNING SIGNS
Provide warning signs for the enclosures of pad-mounted transformers having a nominal rating exceeding 600 volts.
a. When the enclosure integrity of such equipment is specified to be in accordance with IEEE C57.12.28
, such as for pad-mounted transformers, provide self-adhesive warning signs on the outside of
the high voltage compartment door(s). Sign shall be a decal and have nominal dimensions of
178 by 255 mm 7 by 10 inches with the legend "DANGER HIGH VOLTAGE" printed in two lines of nominal
50 mm 2 inch high letters. The word "DANGER" shall be in white letters on a red background
and the words "HIGH VOLTAGE" shall be in black letters on a white background. Decal shall be
Panduit No. PPSO710D72 or approved equal.
[b. When such equipment is guarded by a fence, mount signs on the fence. Provide metal signs
having nominal dimensions of 355 by 255 mm 14 by 10 inches with the legend "DANGER HIGH VOLTAGE
KEEP OUT" printed in three lines of nominal 75 mm 3 inch high white letters on a red and black
field.]
2.4 GROUNDING AND BONDING
UL 467. Provide grounding and bonding as specified in Section[ 33 71 02.00 20 UNDERGROUND ELECTRICAL DISTRIBUTION][
33 70 02.00 10 ELECTRICAL DISTRIBUTION SYSTEM, UNDERGROUND].
[2.5 PADLOCKS
NOTE: Designer must assure that Section 08 71 00 DOOR HARDWARE is included
and is edited to include padlocks.
Do not use this paragraph for NAVFAC Atlantic projects.
Provide padlocks for pad-mounted equipment [and for each fence gate]. Padlocks shall be keyed [alike] [as directed
by the Contracting Officer]. Padlocks shall comply with Section 08 71 00 DOOR HARDWARE .
]2.6 CAST-IN-PLACE CONCRETE
NOTE: Use the first bracketed paragraph when project includes a concrete section
in Division 3; otherwise, the second bracketed paragraph may be used. Coordinate
requirements with Section 03 31 00.00 10 CAST-IN-PLACE STRUCTURAL CONCRETE or
Section 03 30 00 CAST-IN-PLACE CONCRETE. Use Section 03 30 00 CAST-IN-PLACE
for Navy projects and Section 03 31 00.00 10 CAST-IN-PLACE STRUCTURAL CONCRETE
for other projects.
[Concrete associated with electrical work for other than encasement of underground ducts shall be 30 MPa 4000
psi minimum 28-day compressive strength unless specified otherwise. All concrete shall conform to the requirements
of Section[ 03 30 00 CAST-IN-PLACE CONCRETE][ 03 31 00.00 10 CAST-IN-PLACE STRUCTURAL CONCRETE].]
NOTE: If concrete requirements are detailed and no cast-in-place section is
to be included in the project specification, refer to Section 03 30 00 CAST-IN-PLACE
CONCRETE or Section 03 31 00.00 10 CAST-IN-PLACE STRUCTURAL CONCRETE and select
such portions as needed to provide complete requirements in addition to the
requirements below.
[Shall be composed of fine aggregate, coarse aggregate, portland cement, and water so proportioned and mixed
as to produce a plastic, workable mixture. Fine aggregate shall be of hard, dense, durable, clean, and uncoated
sand. The coarse aggregate shall be reasonably well graded from 4.75 mm to 25 mm 3/16 inch to 1 inch. The fine
and coarse aggregates shall be free from injurious amounts of dirt, vegetable matter, soft fragments or other
deleterious substances. Water shall be fresh, clean, and free from salts, alkali, organic matter, and other
impurities. Concrete associated with electrical work for other than encasement of underground ducts shall be
30 MPa 4000 psi minimum 28-day compressive strength unless specified otherwise. Slump shall not exceed 100 mm
4 inches. Retempering of concrete will not be permitted. Exposed, unformed concrete surfaces shall be given
a smooth, wood float finish. Concrete shall be cured for a period of not less than 7 days, and concrete made
with high early strength portland cement shall be repaired by patching honeycombed or otherwise defective areas
with cement mortar as directed by the Contracting Officer. Air entrain concrete exposed to weather using an
air-entraining admixture conforming to ASTM C 260. Air content shall be between 4 and 6 percent.]
2.7 SOURCE QUALITY CONTROL
NOTE: Use "reserves the right to" on all projects, except those for SOUTHNAVFACENGCOM.
2.7.1 Transformer Test Schedule
The Government [reserves the right to][will] witness tests. Provide transformer test schedule for tests to be
performed at the manufacturer's test facility. Submit required test schedule and location, and notify the Contracting
Officer 30 calendar days before scheduled test date. Notify Contracting Officer 15 calendar days in advance
of changes to scheduled date.
a. Test Instrument Calibration
1. The manufacturer shall have a calibration program which assures that all applicable test
instruments are maintained within rated accuracy.
2. The accuracy shall be directly traceable to the National Institute of Standards and Technology.
3. Instrument calibration frequency schedule shall not exceed 12 months for both test floor
instruments and leased specialty equipment.
4. Dated calibration labels shall be visible on all test equipment.
5. Calibrating standard shall be of higher accuracy than that of the instrument tested.
6. Keep up-to-date records that indicate dates and test results of instruments calibrated or
tested. For instruments calibrated by the manufacturer on a routine basis, in lieu of third
party calibration, include the following:
(a) Maintain up-to-date instrument calibration instructions and procedures for each test instrument.
(b) Identify the third party/laboratory calibrated instrument to verify that calibrating standard
is met.
2.7.2 Design Tests
IEEE C57.12.00, and IEEE C57.12.90. Section 5.1.2 in IEEE C57.12.80 states that "design tests are made only
on representative apparatus of basically the same design." Submit design test reports (complete with test data,
explanations, formulas, and results), in the same submittal package as the catalog data and drawings for[ each
of] the specified transformer(s). Perform design tests prior to the award of this contract.
a. Tests shall be certified and signed by a registered professional engineer.
b. Temperature rise: "Basically the same design" for the temperature rise test means a pad-mounted
transformer with the same coil construction (such as wire wound primary and sheet wound secondary), the
same kVA, the same cooling type (ONAN), the same temperature rise rating, and the same insulating liquid
as the transformer specified.
c. Lightning impulse: "Basically the same design" for the lightning impulse dielectric test means a
pad-mounted transformer with the same BIL, the same coil construction (such as wire wound primary and
sheet wound secondary), and a tap changer, if specified. Design lightning impulse tests shall include
the primary windings only of that transformer.
1. IEEE C57.12.90, paragraph 10.3 entitled "Lightning Impulse Test Procedures," and IEEE C57.98
.
2. State test voltage levels.
3. Provide photographs of oscilloscope display waveforms or plots of digitized waveforms with
test report.
d. Lifting and moving devices: "Basically the same design" requirement for the lifting and moving devices
test means a test report confirming that the lifting device being used is capable of handling the weight
of the specified transformer in accordance with IEEE C57.12.34.
e. Pressure: "Basically the same design" for the pressure test means a pad-mounted transformer with
a tank volume within 30 percent of the tank volume of the transformer specified.
f. Short circuit: "Basically the same design" for the short circuit test means a pad-mounted transformer
with the same kVA as the transformer specified.
2.7.3 Routine and Other Tests
IEEE C57.12.00. Routine and other tests shall be performed by the manufacturer on[ each of] the actual transformer(s)
prepared for this project to ensure that the design performance is maintained in production. Submit test reports,
by serial number and receive approval before delivery of equipment to the project site. Required tests and testing
sequence shall be as follows:
a. Cold resistance measurements (provide reference temperature)
b. Phase relation
c. Ratio
d. No-load losses (NLL) and excitation current
e. Load losses (LL) and impedance voltage
f. Dielectric
1. Impulse
2. Applied voltage
3. Induced voltage
g. Leak
h. Dissolved gas analysis (DGA)
PART 3 EXECUTION
3.1 INSTALLATION
Electrical installations shall conform to IEEE C2, NFPA 70, and to the requirements specified herein. Provide
new equipment and materials unless indicated or specified otherwise.
3.2 GROUNDING
NOTE: For SOUTHNAVFACENGCOM projects, delete this paragraph and its subparagraphs,
and use optional paragraph entitled "Transformer Grounding" instead.
NOTE: Where rock or other soil conditions prevent obtaining a specified ground
value, other methods of grounding should be specified. Where it is impractical
to obtain the indicated ground resistance values, make every effort within reason
to obtain ground resistance values as near as possible to the indicated values.
NFPA 70 and IEEE C2, except that grounding systems shall have a resistance to solid earth ground not exceeding
5 ohms.
3.2.1 Grounding Electrodes
Provide driven ground rods as specified in Section[ 33 71 02.00 20 UNDERGROUND ELECTRICAL DISTRIBUTION][
33 70 02.00 10 ELECTRICAL DISTRIBUTION SYSTEM, UNDERGROUND]. Connect ground conductors to the upper end of ground
rods by exothermic weld or compression connector. Provide compression connectors at equipment end of ground
conductors.
3.2.2 Pad-Mounted Transformer Grounding
NOTE: Ensure plans show the secondary neutral grounding conductor sized in
accordance with NFPA 70 and the primary neutral grounding conductor when required.
Provide separate copper grounding conductors and connect them to the ground loop as indicated. When work in
addition to that indicated or specified is required to obtain the specified ground resistance, the provision
of the contract covering "Changes" shall apply.
3.2.3 Connections
Make joints in grounding conductors and loops by exothermic weld or compression connector. Install exothermic
welds and compression connectors as specified in Section[ 33 71 02.00 20 UNDERGROUND ELECTRICAL DISTRIBUTION][
33 70 02.00 10 ELECTRICAL DISTRIBUTION SYSTEM, UNDERGROUND].
3.2.4 Grounding and Bonding Equipment
UL 467, except as indicated or specified otherwise.
[3.3 TRANSFORMER GROUNDING
NOTE: For SOUTHNAVFACENGCOM projects, use this paragraph in lieu of the previous
paragraph entitled "GROUNDING."
Provide a 1/0 bare copper-ground girdle around transformer. Girdle shall be buried 305 mm one foot deep and
placed 915 mm 3 feet laterally from the transformer enclosure. Connect girdle to enclosure at two opposite places
using 1/0 copper. Exothermically weld joints.
]3.4 INSTALLATION OF EQUIPMENT AND ASSEMBLIES
Install and connect pad-mounted transformers furnished under this section as indicated on project drawings, the
approved shop drawings, and as specified herein.
3.4.1 Meters and Current Transformers
NEMA C12.1.
3.5 FIELD APPLIED PAINTING
Where field painting of enclosures is required to correct damage to the manufacturer's factory applied coatings,
provide manufacturer's recommended coatings and apply in accordance with manufacturer's instructions.
[3.6 WARNING SIGN MOUNTING
Provide the number of signs required to be readable from each accessible side, but space the signs a maximum
of 9 meters 30 feet apart.
]3.7 FOUNDATION FOR EQUIPMENT AND ASSEMBLIES
NOTE: Mounting slab connections may have to be given in detail depending on
the requirements for the seismic zone in which the requirement is located.
Include construction requirements for concrete slab only if slab is not detailed
in drawings. At some activities, curbs or raised edges may also be required
around liquid filled transformer.
Mount transformer on concrete slab. Unless otherwise indicated, the slab shall be at least 200 mm 8 inches thick,
reinforced with a 152 mm x 152 mm - MW19 by MW19 (6 by 6 - W2.9 by W2.9) 6 by 6 - W2.9 by W2.9 mesh, placed uniformly
100 mm 4 inches from the top of the slab. Place the slab on a 150 mm 6 inch thick, well-compacted gravel base.
Top of concrete slab shall be approximately 100 mm 4 inches above finished grade with gradual slope for drainage.
Edges above grade shall have 15 mm 1/2 inch chamfer. Slab shall be of adequate size to project at least 200
mm 8 inches beyond the equipment.
Stub up conduits, with bushings, 50 mm 2 inches into cable wells in the concrete pad. Coordinate dimensions
of cable wells with transformer cable training areas.
3.7.1 Cast-In-Place Concrete
NOTE: Use the first bracketed option when project includes a concrete section
in Division 3; otherwise, the second bracketed option may be used.
Cast-in-place concrete work shall conform to the requirements of[ Section[ 03 30 00 CAST-IN-PLACE CONCRETE][
03 31 00.00 10 CAST-IN-PLACE STRUCTURAL CONCRETE]][ ACI 318M].
[3.7.2 Sealing
NOTE: Require sealing of holes (windows) in the concrete pad if rodent intrusion
is a problem.
When the installation is complete, the Contractor shall seal all conduit and other entries into the equipment
enclosure with an approved sealing compound. Seals shall be of sufficient strength and durability to protect
all energized live parts of the equipment from rodents, insects, or other foreign matter.
]3.8 FIELD QUALITY CONTROL
3.8.1 Performance of Acceptance Checks and Tests
Perform in accordance with the manufacturer's recommendations and include the following visual and mechanical
inspections and electrical tests, performed in accordance with NETA ATS.
3.8.1.1 Pad-Mounted Transformers
a. Visual and mechanical inspection
1. Compare equipment nameplate information with specifications and approved shop drawings.
2. Inspect physical and mechanical condition. Check for damaged or cracked insulators and
leaks.
3. Inspect all bolted electrical connections for high resistance using low-resistance ohmmeter,
verifying tightness of accessible bolted electrical connections by calibrated torque-wrench
method, or performing thermographic survey.
4. Verify correct liquid level in tanks.
5. Perform specific inspections and mechanical tests as recommended by manufacturer.
6. Verify correct equipment grounding.
[7. Verify the presence of transformer surge arresters.]
b. Electrical tests
1. Perform resistance measurements through all bolted connections with low-resistance ohmmeter.
2. Verify that the tap-changer is set at specified ratio.
3. Verify proper secondary voltage phase-to-phase and phase-to-neutral after energization and
prior to loading.
3.8.1.2 Current Transformers
a. Visual and mechanical inspection
1. Compare equipment nameplate data with specifications and approved shop drawings.
2. Inspect physical and mechanical condition.
3. Verify correct connection.
4. Verify that adequate clearances exist between primary and secondary circuit.
5. Inspect all bolted electrical connections for high resistance using low-resistance ohmmeter,
verifying tightness of accessible bolted electrical connections by calibrated torque-wrench
method, or performing thermographic survey.
6. Verify that required grounding and shorting connections provide good contact.
b. Electrical tests
1. Perform resistance measurements through all bolted connections with low-resistance ohmmeter,
if applicable.
2. Perform insulation-resistance test.
3. Perform a polarity test.
4. Perform a ratio-verification test.
3.8.1.3 Watthour Meter
[a. Visual and mechanical inspection
1. Compare equipment nameplate data with specifications and approved shop drawings.
2. Inspect physical and mechanical condition.
3. Verify tightness of electrical connections.]
b. Electrical tests
1. Calibrate watthour meters according to manufacturer's published data.
2. Verify that correct multiplier has been placed on face of meter, where applicable.
3. Verify that current transformer secondary circuits are intact.
3.8.1.4 Grounding System
a. Visual and mechanical inspection
1. Inspect ground system for compliance with contract plans and specifications.
NOTE: For SOUTHNAVFACENGCOM projects, delete "Electrical tests" below.
b. Electrical tests
1. Perform ground-impedance measurements utilizing the fall-of-potential method. On systems
consisting of interconnected ground rods, perform tests after interconnections are complete.
On systems consisting of a single ground rod perform tests before any wire is connected. Take
measurements in normally dry weather, not less than 48 hours after rainfall. Use a portable
ground testing megger in accordance with manufacturer's instructions to test each ground or
group of grounds. Equip the instrument with a meter reading directly in ohms or fractions thereof
to indicate the ground value of the ground rod or grounding systems under test.
2. Submit the measured ground resistance of each ground rod and grounding system, indicating
the location of the rod and grounding system. Include the test method and test setup (i.e.,
pin location) used to determine ground resistance and soil conditions at the time the measurements
were made.
3.8.2 Follow-Up Verification
Upon completion of acceptance checks and tests, the Contractor shall show by demonstration in service that circuits
and devices are in good operating condition and properly performing the intended function. As an exception to
requirements stated elsewhere in the contract, the Contracting Officer shall be given 5 working days advance
notice of the dates and times of checking and testing.