edited to delete specification requirements for
processes, items, or designs that are not included in the project -- and specifiers notes such as
these. To seek a variance from requirements in the specifications that are applicable, contact
the Engineering Standards Manual Electrical
POC
. Please contact POC with suggestions for
improvement as well.

When assembling a specification package, include applicable specifications from all Divisions,
especially Division 1, General requirements.

Specification developed for ML-4 projects. For ML-1, 2, and 3 applications, additional
requirements and independent reviews should be added if increased confidence in procurement
or execution is desired; see ESM Chapter 1 Section Z10 Specifications and Quality sections.

In addition to a pad for the transformer, containment for transformer oil may be required by ESM
Chapter 7, Section G4010, Parts 10.4 and 18.0 environmental or fire protection reasons. Detail
such containment structures on the Drawings.
***********************************************************************************************************
PART 1 GENERAL
1.1 SECTION
INCLUDES
A.
Furnish and install rough-in for pad-mounted utility transformer including the
following:
1. Transformer pad.
2. Underground ductbank for medium-voltage cables.
3. Underground secondary service.
4. Grounding provisions.
*************************************************************************************************************
Edit the following article to match project requirements; delete if containment is not required.
Refer to ESM Chapter 7, Section G4010, Parts 10.4 and 18.0 for containment requirements.
Detail containment structures on the Drawings.
*************************************************************************************************************
5. Transformer oil containment provisions.
LANL Project I.D. [ ]

Pad-Mounted Transformer Rough-in
[Rev. 1, July 14, 2008]
33 7311 - 1 1.2 LANL
WORK
A.
LANL Utilities will furnish, install, and test pad-mounted transformer and medium-
voltage cables.
1.3 SUBMITTALS
A.
Construction Submittals: None
1.4 QUALITY
ASSURANCE
A.
Comply with the requirements of the National Electrical Code and IEEE C2
National Electrical Safety Code.
1.5
SEQUENCING AND SCHEDULING
A.
Coordinate rough-in for pad-mounted transformer with LANL Utilities.
B.
Schedule an inspection of the transformer pad before concrete is placed.
PART 2 PRODUCTS
2.1
PAD-MOUNTED TRANSFORMER (GFE)
A.
LANL Utilities will furnish a compartment type, self-cooled, tamperproof and
weatherproof pad-mounted transformer that will comply with the following
ANSI/IEEE standards:
1. ANSI/IEEE C57.12.22Requirements for Pad-Mounted, Compartmental-
Type, Self-Cooled, Three-Phase Distribution Transformers with High-Voltage
Bushings; High Voltage, 34500 GrdY/19920 Volts and Below; 2500 kVA and
Smaller.
2. ANSI C57.12.00General Requirements for Liquid-Immersed Distribution,
Power, and Regulating Transformers.
3. ANSI/IEEE C57.12.27Conformance Requirements for Liquid-Filled,
Distribution Transformers Used in Pad-Mounted Installations, Including Unit
Substations.
2.2 CONCRETE
FORMWORK
*************************************************************************************************************
Edit the following article to match specification sections used in Division 3.
*************************************************************************************************************
A.
Refer to Section 03 3001 Reinforced Concrete.
LANL Project I.D. [ ]

Pad-Mounted Transformer Rough-in
[Rev. 1, July 14, 2008]
33 7311 - 2 2.3 CONCRETE
REINFORCEMENT
A.
Use ASTM A615 Grade 60 reinforcing steel bars in transformer concrete pad.
*************************************************************************************************************
Edit the following article to match specification sections used in Division 3.
*************************************************************************************************************
B.
Refer to Section 03 3001 Reinforced Concrete.
2.4 CAST-IN-PLACE
CONCRETE
A.
For transformer pad use concrete with minimum 3000 lb per sq ft strength, 4 to
6 percent entrained air, 3/4 inch maximum size aggregate.
*************************************************************************************************************
Edit the following article to match specification sections used in Division 3.
*************************************************************************************************************
B.
Refer to Section 03 3001 Reinforced Concrete.
2.5
UNDERGROUND DUCTBANKS AND MANHOLES
A.
Refer to Section 33 7119, Electrical Underground Ducts and Manholes.
2.6 CONDUITS
A.
Refer to Section 26 0533, Raceway and Boxes for Electrical Systems.
2.7 GROUNDING
A.
Refer to Section 26 0526, Grounding and Bonding for Electrical Systems.
PART 3 EXECUTION
3.1 EXAMINATION
A.
Examine surfaces and conditions, with Installer present, for compliance with
installation tolerances and other conditions affecting rough-in for pad-mounted
transformer. Do not proceed with installation until unsatisfactory conditions
have been corrected.
3.2
CONDUIT AND DUCT INSTALLATION
A.
Terminate medium-voltage ducts in the primary compartment area of the
transformer pad. Refer to Section 33 0513, Manholes and Structures, for
installation requirements.
LANL Project I.D. [ ]

Pad-Mounted Transformer Rough-in
[Rev. 1, July 14, 2008]
33 7311 - 3 B.
Terminate low-voltage conduits in the secondary compartment of the
transformer. Refer to Section 26 0526, Raceways and Boxes for Electrical
Systems.
C.
Terminate each primary and secondary conduit with a bell end fitting set 2 inches
above the top of the concrete pad.
3.3
CONCRETE PAD INSTALLATION
*************************************************************************************************************
Refer to Drawing ST-G4010-38 for transformer concrete pad dimensions. Project-specific
transformer pad construction details should be included in the Drawings.
*************************************************************************************************************
A.
Install reinforced concrete pad of suitable dimensions for pad-mounted
transformer.
*************************************************************************************************************
Edit the following article to match project requirements; delete if containment is not required.
Refer to ESM Chapter 7, Section G4010, Parts 10.4 and 18.0 for containment requirements.
Detail containment structures on the Drawings.
*************************************************************************************************************
B.
Install reinforced concrete transformer oil containment structure as indicated on
the Drawings.
C.
Prepare level, compacted pad site in accordance with Section 31 2000, Earth
Moving
*************************************************************************************************************
Edit the following article to match specification sections used in Division 3 and project
requirements. A more substantial perimeter beam may be dictated by geotechnical conditions.
*************************************************************************************************************
D.
Form transformer pad [and oil containment structure] in accordance with Section
[03 3001, Reinforced Concrete]
1. Provide pad with perimeter turn down beam that is not less than 8 inches
wide and extends not less than 12 inches below grade.
*************************************************************************************************************
Edit the following article to match specification sections used in Division 3 and project
requirements.
*************************************************************************************************************
E.
Reinforce transformer pad [and oil containment structure] in accordance with
Section [03 3001, Reinforced Concrete] and as detailed on the Drawings.
1. Extend reinforcing into perimeter beam.
2. Provide not less than 2 inches of concrete cover over reinforcing steel.
*************************************************************************************************************
Edit the following article to match specification sections used in Division 3.
*************************************************************************************************************
LANL Project I.D. [ ]

Pad-Mounted Transformer Rough-in
[Rev. 1, July 14, 2008]
33 7311 - 4 LANL Project I.D. [ ]

Pad-Mounted Transformer Rough-in
[Rev. 1, July 14, 2008]
33 7311 - 5
F.
Place concrete in accordance with Section [03 3001, Reinforced Concrete].
Provide wood float finish with no depressions.
1. Chamfer top edges and corners.
2. Cure concrete not less than seven days before installing equipment.
G.
Install not less than four 5/8 inch diameter galvanized steel anchor bolts set at
least 4 inches into pad to anchor pad-mounted transformer to pad.
3.4 GROUNDING
A.
Install a 10 ft driven ground rod below the secondary compartment area of the
transformer pad. Provide 4/0 AWG ground cable and compression ground lug to
connect ground rod to transformer ground pad in the secondary compartment.
B.
Terminate medium-voltage duct bank ground cable in primary compartment area
of the transformer pad. Provide compression ground lug to connect ground cable
to transformer gro