UNITED STATES DEPARTMENT OF AGRICULTURE

Rural Utilities Service

**BULLETIN 1751F-644**

**SUBJECT: [Underground Plant Construction]{.underline}**

**TO:** All Telecommunications Borrowers

RUS Telecommunications Staff

**EFFECTIVE DATE:** August 28, 2002

**OFFICE OF PRIMARY INTEREST:** Outside Plant Branch, Telecommunications
Standards Division

**INSTRUCTIONS:** This bulletin supersedes RUS Bulletin 1751F-644,
"Underground Plant Construction," issued May 14, 1998.

**AVAILABILITY:** This bulletin is available on the Internet at
http://www.usda.gov/rus/telecom/publications/bulletins.htm

**PURPOSE:** This bulletin provides RUS borrowers, consulting engineers,
contractors and other interested parties with information on the
construction of underground plant facilities. This bulletin also
provides information on the construction of poured-in-place underground
cable vaults.

[Roberta D. Purcell]{.underline} [8/28/02]{.underline}

Roberta D. Purcell Date

Assistant Administrator

Telecommunications Program

**TABLE OF CONTENTS**

Abbreviations \...\...\...\...\...\...\...\...\...\...\...\...\...\.....
3

Definitions
\...\...\...\...\...\...\...\...\...\...\...\...\...\...\.... 4

1\. General
\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\..... 6

2\. Inspection of Construction \...\...\...\...\...\...\...\...\...\....
7

3\. UCV Excavating and Grading \...\...\...\...\...\...\...\...\...\...
11

4\. Conduit Excavating, Grading, and Laying \...\...\...\...\..... 14

5\. Backfilling of Conduit Trenches and Conduit Sealing \..... 18

6\. Subsidiary Conduit Installation \...\...\...\...\...\...\...\.... 19

7\. Concrete and Aggregate for Poured-In-Place UCVs and

for Conduit Protection and Encasement \...\...\...\...\...\.... 20

8\. Conduit Rodding and Cleaning \...\...\...\...\...\...\...\...\....
25

9\. Cable Location and Conduit Selection \...\...\...\...\...\..... 25

10\. Cable Reel and Apparatus Set-Up \...\...\...\...\...\...\...\....
26

11\. Pulling Lines and Attachments \...\...\...\...\...\...\...\...\...
26

12\. Cable Feeding and Pulling \...\...\...\...\...\...\...\...\...\....
27

13\. Pulling Cables into Subsidiary Conduits \...\...\...\...\..... 28

14\. Safety Precautions
\...\...\...\...\...\...\...\...\...\...\...\..... 29

15\. Handling and Care of Materials During Construction \...\... 30

16\. Repair of Cables Damaged During Construction \...\...\...\... 31

17\. Preparation for Splicing or Termination \...\...\...\...\..... 31

18\. Installation Procedures for Filled Cables

in Cold Weather \...\...\...\...\...\...\...\...\...\...\...\...\.....
31

19\. Assembly Units and Acceptance Testing \...\...\...\...\...\.... 32

**TABLES & FIGURES**

Table 1 Poured-In-Place UCV Excavations - Minimum Lengths

and Widths - Without Sheeting Materials \...\...\...\... 12

Table 2 Poured-In-Place UCV Excavations - Minimum Lengths

and Widths - With Sheeting Materials \...\...\...\...\... 12

Table 3 Poured-In-Place UCV Excavations - Bracing and

Shoring - Firm or Hard Soils \...\...\...\...\...\...\..... 13

Table 4 Poured-In-Place UCV Excavations - Bracing and

Shoring - Cracking or Crumbling Soils \...\...\...\..... 14

Table 5 Poured-In-Place UCV Excavations - Bracing and

Shoring - Soft Sands or Loose Soils \...\...\...\...\.... 14

Table 6 Conduit Trench Excavations - Bracing and Sheet

Piling - All Trench Widths - Soft, Sandy, or

Loose Soils \...\...\...\...\...\...\...\...\...\...\...\...\.... 15

Table 7 Conduit Trench Excavations - Bracing and Sheet

Piling - Trench Widths of 4 ft (1.2 m) or Less -

Cracking or Crumbling Soils \...\...\...\...\...\...\...\... 15

**TABLES & FIGURES - Continued**

Table 8 Conduit Trench Excavations - Bracing and Sheet

Piling - Trench Widths Greater than 4 ft (1.2 m)

Cracking or Crumbling Soils \...\...\...\...\...\...\...\... 16

Table 9 Trial Mixes for Cubic Yard of Concrete \...\...\...\.... 22

Table 10 Fine Aggregate Grading \...\...\...\...\...\...\...\...\.....
24

Table 11 Coarse Aggregates - Usage, Sieve Sizes, and

Aggregate Sizes \...\...\...\...\...\...\...\...\...\...\...\... 24

Figure 1 Example of Construction Details --

Poured-In-Place UCV Types A, L, T, J, X, and Y \..... 33

Figure 2 Example of Construction Details --

Poured-In-Place UCV Type V \...\...\...\...\...\...\...\.... 34

Figure 3 Subsidiary Conduit Installation -

Riser Pole Example \...\...\...\...\...\...\...\...\...\...\... 35

Figure 4 UCV Underground Cable and Splice Case

Racking Diagram Example \...\...\...\...\...\...\...\...\.... 36

Figure 5 Pulling Line Attachment Examples \...\...\...\...\...\.... 37

**INDEX**:

Outside Plant

Construction, Underground

Telecommunications

**ABBREVIATIONS**

°C Degrees Celsius

cm Centimeter

CT Construction Truck

°F Degrees Fahrenheit

ft Foot or feet

ft/min Feet per minute

kg Kilograms

lbs Pounds

in. Inches

m Meter

m^3^ Cubic Meters

m/min Meters per minute

mm Millimeter

MPa Megapascals

psi Pounds per square inch

NESC National Electrical Safety Code

**ABBREVIATIONS - Continued**

R/W Right-of-way

RUS Rural Utilities Service

TE&CM Telecommunications Engineering and Construction Manual

UCV Underground Cable Vault

UCVs Underground Cable Vaults

**DEFINITIONS**

**[Aggregate]{.underline}:** The mineral materials such as sand or stone
used in making concrete.

**[Backfill]{.underline}:** Materials such as sand, crushed stone, or
soil, which are used to refill a trench after conduits or cables have
been laid therein.

**[Cable Rack]{.underline}:** A device usually secured to the wall of an
underground cable vault (UCV), cable raceway, or building to provide
support for cables.

**[Conduit]{.underline}:** A tubular raceway for holding wires or
cables, which is designed expressly for, and used solely for, this
purpose.

**[Conduit Run]{.underline}:** An arrangement of conduit providing one
or more continuous conduits between two points.

**[Construction Drawings]{.underline}:** The drawings developed through
the staking process and used to guide the construction of outside plant
facilities.

**[Eligible Country]{.underline}:** Any country that applies with
respect to the United States an agreement ensuring reciprocal access for
United States products and services and United States suppliers to the
market of that country, as determined by the Unites States Trade
Representative.

**[Resident]{.underline}:** The competent representative of the Engineer
who is delegated full time "on site" Construction Administration
responsibilities of the Engineer.

**[Right-of-Way]{.underline}:** The strip of land over which facilities
such as highways, railroads, power lines, other utilities, or
telecommunication lines are constructed.

**[Rodding]{.underline}:** A device that can be either pulled or pushed
through a conduit that cleans the conduit of stones, rubble, etc. and
prepares the conduit to receive the cable.

**DEFINITIONS - Continued**

**[RUS Accepted (Material and Equipment)]{.underline}:** Equipment which
RUS has reviewed and determined that:

a.  Final assembly or manufacture of the equipment is

completed in the United States, its territories and

possessions, or in an eligible country;

b\. The cost of components within the material or equipment

manufactured in the United States, its territories and

possessions, or in an eligible country is more than 50

percent of the total cost of all components used in the

material or equipment; and

c\. The material or equipment is suitable for use on

systems of RUS telecommunications borrowers.

**[RUS Technically Accepted (Material and Equipment)]{.underline}:**
Equipment which RUS has reviewed and determined that the material or
equipment is suitable for use on systems of RUS telecommunications
borrowers but the material or equipment does not satisfy both paragraph
(a) and (b) of this definition:

a\. Final assembly or manufacture of the equipment is

not completed in the United States, its territories and

possessions, or in an eligible country; and

b\. The cost of components within the material or equipment

manufactured in the United States, its territories and

possessions, or in an eligible country is 50 percent or

less than the total cost of all components used in the

material or equipment.

**[Sieve]{.underline}:** A wire mesh or closely perforated metal used
for straining, sifting, or ricing.

**[Stringer]{.underline}:** A long, heavy horizontal timber used for any
of several connective or supportive purposes.

**[Subsidiary Conduit]{.underline}:** A minor or spur conduit route
leading from an underground cable vault or jointing chamber to a
building or distribution point.

**[Underground Cable Vault (UCV)]{.underline}:** A subsurface chamber,
large enough for a person to enter for the purpose of installing cables
and other devices, and for making connections and tests.

**1. GENERAL**

**1.1** This bulletin discusses construction of underground plant
facilities using filled copper or fiber optic cables. The information
and recommendations in this bulletin are advisory.

**1.2** Some of the work items associated with underground plant
construction are as follows:

a\. Pre-installation inspection of copper cables and fiber

optic cables;

b\. Pre-installation inspection of precast underground cable

vaults (UCVs) and conduits;

c\. Trenching and installation of conduit runs;

d.  Excavation of precast or poured-in-place underground

> cable vault (UCV) pits;

e\. Installation and inspection of bracing for precast or

poured-in-place UCV pits;

f\. Installation of precast UCVs;

g\. Construction of poured-in-place UCVs;

h\. The installation of filled copper or fiber optic cables

in conduits and UCVs;

i\. Installation of underground filled splice cases for

copper or fiber optic cables;

j\. Splicing of copper cables and connection of shield

bonds and related grounding;

k\. Splicing of fiber optic cables;

l\. Connection of armor bonds and related grounding for

underground, armored, fiber optic cables;

m\. Conducting acceptance tests.

**1.3** Information for the design, splicing, acceptance testing, and
construction of underground plant facilities can be found in the
following Rural Utilities Service (RUS) documents:

a.  RUS Form 515 RUS Telecommunications System Construction

> Contract (Labor and Materials);

b\. RUS Bulletin 1751F-643, Underground Plant Design;

c\. RUS Bulletin 1753F-151, Specifications and Drawings for

Construction of Underground Plant, RUS Form 515b;

d\. RUS Bulletin 1753F-201(PC-4), RUS Standard for

Acceptance Tests and Measurements of Telecommunications

Plant;

e\. RUS Bulletin 1753F-205(PE-39), RUS Specification for

Filled Telephone Cables;

f\. RUS Bulletin 1753F-208(PE-89), RUS Specification for

Filled Telephone Cables with Expanded Insulation;

g\. RUS Bulletin 1753F-401(PC-2), RUS Standard for Splicing

Copper and Fiber Optic Cables;

h\. RUS Bulletin 1753F-601(PE-90), RUS Specification for

Filled Fiber Optic Cables; and

i\. Latest edition of the National Electrical Safety

Code (NESC).

**2. INSPECTION OF CONSTRUCTION**

**2.1** The construction of underground plant facilities should be
inspected. This inspection should be accomplished by having the resident
or resident's assigned inspector present at all times during the
underground plant construction operation. The resident or resident's
assigned inspector also should ensure that correct conduit sizes and
number of conduits; correct UCV sizes; correct pair sizes, gauges, and
types of copper cables; and the correct number of optical fibers, types
of optical fibers, and types of fiber optic cables are installed and
free of damage during the underground plant construction operations.

**2.2** When more than one underground plant construction operation is
being performed at the same time, each operation should be inspected.
During the installation of the conduit and UCV system, construction may
be stopped pending the resident's decision concerning proposed changes
in the construction route from that shown on the construction drawings.
Undue delays in making such decisions are costly to the borrower and
should be avoided.

**2.3** All reels of filled copper or fiber optic cables; conduit
sections; and precast UCVs should be inspected before installation for
visual signs of damage. In addition, filled copper or fiber optic cable
ends should be sealed to prevent moisture entry into the cores of copper
or fiber optic cables during transportation, in storage, and during
placement.

**2.4** The underground plant construction route should be inspected
before beginning construction. When selecting the underground plant
construction route, the convenience and ease of installation should be
considered providing the quality of construction is not decreased and
construction costs to the borrower are not substantially increased,
which would affect future operation and maintenance of the
telecommunications system.

**2.5** Cables, conduit runs, UCVs, etc., as well as, the equipment and
procedures should be continuously inspected during the installation to
prevent damage to the cables, conduits, UCVs, etc., and to ensure that
proper depths of conduit runs and UCVs are maintained at all times.
Conduit runs should be checked for damage at severe changes in grade and
corner angles. The resident should make certain that conduit runs are
properly installed in open trenches, that trenches are properly
backfilled, and that ground surfaces are restored to their previous
conditions. The resident should also make certain that UCVs are properly
installed in open vault pits, that vault pits are properly backfilled,
and ground surfaces are restored to their previous conditions.

**2.6** Sequential markings on the outer jackets of cables are provided
to facilitate the inventory of cable units. The resident and the
contractor should agree on the inventory of underground plant units as
they are installed. Construction drawings should be appropriately marked
so they can be used as permanent records of all plant items.

**2.7** Road and ground surfaces should be inspected to determine if the
surfaces have been damaged by the trenching and cable placement
equipment. If surfaces have been damaged, surfaces should be repaired
and reinspected. If repairs are necessary, repairs should be performed
in accordance with Federal, State, or local codes, as set forth in, the
RUS Telecommunications System Construction Contract (RUS Form 515).

**2.8** Conduit runs should be inspected during construction to
determine that:

a\. Conduits have been properly installed in trenches;

b\. Multi-duct conduit formations have the proper vertical

and horizontal spacings in trenches;

c\. Conduit sections have been properly jointed;

d\. Proper bend radii of curved conduit sections have

been maintained;

e\. Required slope and depth of conduits have been

maintained;

f\. Concrete encasements have been properly installed,

when required;

g\. Concrete bases have been properly installed,

when required; and

h\. Top protection has been properly installed,

when required.

**2.9** Precast and poured-in-place UCVs should be inspected during
construction to determine that:

a\. UCVs have been properly installed in vault pits;

b\. UCV collars, frames, and covers have been properly

installed;

c\. Cable racks and their associated spacings have been

properly installed on UCV walls;

d\. Underground filled copper or fiber optic splice cases

are supported on racks;

e\. Underground filled copper or fiber optic cables are

supported on cable racks;

f\. Vacant conduit ends are sealed; and

g\. Cable tags have been marked with the proper information

per RUS Bulletin 1753F-401(PC-2),RUS Standard for

Splicing Copper and Fiber Optic Cables.

**2.10** Underground splices and cases should be inspected during
construction to ensure that:

a\. Cable jackets have been properly prepared;

b\. Copper cable conductors have been properly spliced;

c\. Optical fibers have been properly spliced;

d\. Buffer tubes containing the optical fibers have a

sufficient amount of slack;

e\. Shields of copper cables have been bonded

and grounded;

f\. Armors of armored, filled, fiber optic cables have been

bonded and grounded;

g\. Encapsulating compounds have been properly mixed and

applied; and

h\. Underground filled splice cases have been

properly installed.

**2.11** Construction drawings should be accurately marked to indicate
the following:

a\. Routing of conduit and UCV system;

b\. Locations of UCVs, buildings, and/or pole risers in

relation to streets, roads, buildings, poles, or other

obstructions;

c\. Distances between UCVs (wall-to-wall measurements),

UCVs to pole risers (wall-to-pole measurements) and UCVs

to buildings (wall-to-building measurements);

d\. Conduit configurations, sizes and types between UCVs,

UCVs to pole risers, and UCVs to buildings;

e\. Locations of existing and proposed cables and conduits

in which cables either exist or are to be installed;

f\. UCV, cable vault, and building cable racking diagrams

indicating the positions of all existing and proposed

cables and cable stubs;

g\. Conduit configurations indicating particular cable

assignments;

h\. Exact cable (splice-to-splice) cut lengths for all

proposed cables to be installed in conduits;

i\. Pole and building risers indicating splice locations,

supporting structures, cable attachment methods, and

physical protection, when required;

j\. Lengths, pair sizes, gauges, and types of copper cables;

k\. Lengths, number and types of optical fibers, and types

of fiber optic cables;

l\. Locations of underground filled splice cases; and

m\. Locations of other underground utilities and obstacles.

**2.12** Special care should be exercised to avoid damage to fences,
trees, lawns, and shrubs during installations of conduit and UCV
systems. Damages to fences, trees, lawns, and shrubs should be repaired
in accordance with RUS Bulletin 1753F-151, Specifications and Drawings
for Construction of Underground Plant, RUS Form 515b.

**2.13** Trenching operations of conduit and UCV systems within areas of
subsurface structures should be carried out in a manner that will avoid
accidental contact of the digging tools with such structures. The
equipment, which is used for such operations, should be operated only by
qualified personnel. When foreign subsurface structures are encountered
such as power cables, Community Antenna Television cables, gas lines,
etc., installations of conduit and UCV systems should be performed in
accordance with the requirements of the latest edition of the NESC or
Federal, State, or local codes. [Where Federal, State, or local codes
are more stringent than the NESC, installations of conduit and UCV
systems should be performed in accordance with the more stringent
codes]{.underline}.

**3. UCV EXCAVATING AND GRADING**

**3.1** Lengths, widths, depths, bracing, and sheeting, if required, of
excavations for precast UCVs should be in accordance with precast UCV
manufacturers' recommendations

**3.2** Lengths and widths of excavations for poured-in-place UCVs
should be constructed with interior dimensions as specified on
construction drawings and with walls of necessary thicknesses at points
of minimum dimensions. Figures 1 and 2 of this bulletin provide examples
of the construction details containing the above mentioned interior
dimensions of the UCVs. Where sheeting is required to prevent cave-ins,
poured-in-place UCV excavations should be enlarged accordingly to
account for sheeting materials. Table 1 of this section may be used for
determining minimum lengths and widths of poured-in-place UCV
excavations without sheeting materials. Table 2 of this section may be
used for determining minimum lengths and depths of poured-in-place UCV
excavations with sheeting materials.

TABLE 1

Poured-In-Place UCV Excavations

Minimum Lengths and Widths

Without Sheeting Materials

+------------------------+----------+----------+----------+-----------+
|                        | UCV Wall |          |          |           |
|                        | Thi      |          |          |           |
|                        | cknesses |          |          |           |
|                        |          |          |          |           |
|                        | Inches   |          |          |           |
|                        | (in.)    |          |          |           |
|                        | \[mil    |          |          |           |
|                        | limeters |          |          |           |
|                        | (mm)\]   |          |          |           |
+------------------------+----------+----------+----------+-----------+
|                        | 6 (152)  | 7 (178)  | 8 (203)  | 9 (229)   |
+------------------------+----------+----------+----------+-----------+
| Inside Lengths or      | Lengths  |          |          |           |
|                        | or       |          |          |           |
| Widths of UCVs         | Widths   |          |          |           |
|                        | of       |          |          |           |
| in. \[Centimeters      | Exc      |          |          |           |
| (cm)\]                 | avations |          |          |           |
|                        |          |          |          |           |
|                        | in. (cm) |          |          |           |
+------------------------+----------+----------+----------+-----------+
| 42 (107)               | 54 (137) | 56 (142) | 58 (147) | 60 (152)  |
+------------------------+----------+----------+----------+-----------+
| 48 (122)               | 60 (152) | 62 (157) | 64 (163) | 66 (167)  |
+------------------------+----------+----------+----------+-----------+
| 54 (137)               | 66 (167) | 68 (173) | 70 (178) | 72 (183)  |
+------------------------+----------+----------+----------+-----------+
| 60 (152)               | 72 (183) | 74 (188) | 76 (193) | 78 (183)  |
+------------------------+----------+----------+----------+-----------+
| 66 (167)               | 78 (198) | 80 (203) | 82 (208) | 84 (213)  |
+------------------------+----------+----------+----------+-----------+
| 72 (183)               | 84 (213) | 86 (218) | 88 (223) | 90 (229)  |
+------------------------+----------+----------+----------+-----------+
| 78 (198)               | 90 (229) | 92 (234) | 94 (239) | 96 (244)  |
+------------------------+----------+----------+----------+-----------+
| 84 (213)               | 96 (244) | 98 (249) | 100      | 102 (259) |
|                        |          |          | (254)    |           |
+------------------------+----------+----------+----------+-----------+
| 90 (229)               | 102      | 104      | 106      | 108 (274) |
|                        | (259)    | (264)    | (269)    |           |
+------------------------+----------+----------+----------+-----------+
| 96 (244)               | 108      | 110      | 112      | 114 (289) |
|                        | (274)    | (279)    | (284)    |           |
+------------------------+----------+----------+----------+-----------+
| 102 (259)              | 114      | 116      | 118      | 120 (305) |
|                        | (289)    | (295)    | (300)    |           |
+------------------------+----------+----------+----------+-----------+

TABLE 2

Poured-In-Place UCV Excavations

Minimum Lengths and Widths

With Sheeting Materials

+------------------------+----------+----------+----------+-----------+
|                        | UCV Wall |          |          |           |
|                        | Thi      |          |          |           |
|                        | cknesses |          |          |           |
|                        |          |          |          |           |
|                        | in. (mm) |          |          |           |
+------------------------+----------+----------+----------+-----------+
|                        | 6 (152)  | 7 (178)  | 8 (203)  | 9 (229)   |
+------------------------+----------+----------+----------+-----------+
| Inside Lengths or      | Lengths  |          |          |           |
|                        | or       |          |          |           |
| Widths of UCVs         | Widths   |          |          |           |
|                        | of       |          |          |           |
| in. (cm)\]             | Exc      |          |          |           |
|                        | avations |          |          |           |
|                        |          |          |          |           |
|                        | in. (cm) |          |          |           |
+------------------------+----------+----------+----------+-----------+
| 42 (107)               | 58 (147) | 60 (152) | 62 (157) | 64 (163)  |
+------------------------+----------+----------+----------+-----------+
| 48 (122)               | 64 (163) | 66 (168) | 68 (173) | 70 (178)  |
+------------------------+----------+----------+----------+-----------+
| 54 (137)               | 70 (178) | 72 (183) | 74 (188) | 76 (193)  |
+------------------------+----------+----------+----------+-----------+
| 60 (152)               | 76 (193) | 78 (198) | 80 (203) | 82 (208)  |
+------------------------+----------+----------+----------+-----------+
| 66 (167)               | 82 (208) | 84 (213) | 86 (218) | 88 (223)  |
+------------------------+----------+----------+----------+-----------+
| 72 (183)               | 88 (223) | 90 (229) | 92 (234) | 94 (239)  |
+------------------------+----------+----------+----------+-----------+
| 78 (198)               | 94 (239) | 96 (244) | 98 (249) | 100 (254) |
+------------------------+----------+----------+----------+-----------+
| 84 (213)               | 100      | 102      | 104      | 106 (269) |
|                        | (254)    | (259)    | (264)    |           |
+------------------------+----------+----------+----------+-----------+
| 90 (229)               | 106      | 108      | 110      | 112 (284) |
|                        | (269)    | (274)    | (279)    |           |
+------------------------+----------+----------+----------+-----------+
| 96 (244)               | 112      | 114      | 116      | 118 (300) |
|                        | (284)    | (289)    | (295)    |           |
+------------------------+----------+----------+----------+-----------+
| 102 (259)              | 118      | 120      | 122      | 124 (315) |
|                        | (300)    | (305)    | (310)    |           |
+------------------------+----------+----------+----------+-----------+

**3.3** Depths of poured-in-place UCV excavations should be determined
using the following measurements:

a\. UCV frame depths;

b\. Depths of brick or concrete collars for UCV frames;

c\. UCV roof thicknesses;

d\. UCV headroom; and

e\. UCV floor thicknesses.

If poured-in-place UCV excavations are constructed in wet locations, 4
in. (102 mm) layers of crushed stone should be added to the above
measurements to determine poured-in-place UCV excavation depths. The
crushed stone layers should provide for drainage of water during
construction.

**3.4** Types and amounts of sheeting and bracing required for
poured-in-place UCV excavations vary with soil stability and excavation
depths. Poured-in-place UCV excavations in soils that are considered
firm or hard should be shored and braced as indicated in Table 3 of this
section. For poured-in-place UCV excavations in soils likely to either
crack or crumble, excavations should be shored and braced as indicated
in Table 4 of this section. For poured-in-place UCV excavations in
either soft sands or loose soils, excavations should be shored and
braced as indicated in Table 5 of this section.

TABLE 3

Poured-In-Place UCV Excavations

Bracing and Shoring

Firm or Hard Soils

+-----------+------+-----------+------+-----------+------+-----------+
|           | S    |           | S    |           | C    |           |
|           | heet |           | trin |           | ross |           |
|           | Pi   |           | gers |           | Bra  |           |
|           | ling |           |      |           | cing |           |
+-----------+------+-----------+------+-----------+------+-----------+
| Depth of  | Size | H         | Size | H         | Size | H         |
|           |      | orizontal |      | orizontal |      | orizontal |
| Exac      | in.  |           | in.  |           | in.  |           |
| ava-tions | (mm) | Spacing   | (mm) | Spacing   | (mm) | Spacing   |
|           |      |           |      |           |      |           |
| Feet (ft) |      | ft (m)    |      | ft (m)    |      | ft (m)    |
| \[M       |      |           |      |           |      |           |
| eter(m)\] |      |           |      |           |      |           |
+-----------+------+-----------+------+-----------+------+-----------+
| 5 to 10   | 2 x  | 6         | 4 x  | 4         | 4 x  | 6         |
|           | 6    |           | 6    |           | 6    |           |
| (1.5 to   |      | (1.8)     |      | (1.2)     |      | (1.8)     |
| 3.0)      | (51  |           | (102 |           | (102 |           |
|           | x    |           | x    |           | x    |           |
|           | 152) |           | 152) |           | 152) |           |
+-----------+------+-----------+------+-----------+------+-----------+
| 10 to 20  | 2 x  | Tight     | 6 x  | 4         | 6 x  | 6         |
|           | 6    |           | 6    |           | 6    |           |
| (3.0 to   |      |           |      | (1.2)     |      | (1.8)     |
| 6.1)      | (51  |           | (152 |           | (152 |           |
|           | x    |           | x    |           | x    |           |
|           | 152) |           | 152) |           | 152) |           |
+-----------+------+-----------+------+-----------+------+-----------+

TABLE 4

Poured-In-Place UCV Excavations

Bracing and Shoring

Cracking or Crumbling Soils

+--------+-------+-----------+------+-----------+------+------------+
|        | Sheet |           | S    |           | C    |            |
|        | P     |           | trin |           | ross |            |
|        | iling |           | gers |           | Bra  |            |
|        |       |           |      |           | cing |            |
+--------+-------+-----------+------+-----------+------+------------+
| Depth  | Size  | H         | Size | H         | Size | Horizontal |
| of     |       | orizontal |      | orizontal |      |            |
|        | in.   |           | in.  |           | in.  | Spacing    |
| E      | (mm)  | Spacing   | (mm) | Spacing   | (mm) |            |
| xacava |       |           |      |           |      | ft (m)     |
| -tions |       | ft (m)    |      | ft (m)    |      |            |
|        |       |           |      |           |      |            |
| ft (m) |       |           |      |           |      |            |
+--------+-------+-----------+------+-----------+------+------------+
| 5 to   | 2 x 6 | 3         | 4 x  | 4         | 4 x  | 6          |
| 10     |       |           | 6    |           | 6    |            |
|        | (51 x | (1.0)     |      | (1.2)     |      | (1.8)      |
| (1.5   | 152)  |           | (102 |           | (102 |            |
| to     |       |           | x    |           | x    |            |
| 3.0)   |       |           | 152) |           | 152) |            |
+--------+-------+-----------+------+-----------+------+------------+
| 10 to  | 2 x 6 | Tight     | 6 x  | 4         | 6 x  | 6          |
| 20     |       |           | 6    |           | 6    |            |
|        | (51 x |           |      | (1.2)     |      | (1.8)      |
| (3.0   | 152)  |           | (152 |           | (152 |            |
| to     |       |           | x    |           | x    |            |
| 6.1)   |       |           | 152) |           | 152) |            |
+--------+-------+-----------+------+-----------+------+------------+

TABLE 5

Poured-In-Place UCV Excavations

Bracing and Shoring

Soft Sands or Loose Soils

+--------+-------+-----------+------+-----------+------+------------+
|        | Sheet |           | S    |           | C    |            |
|        | P     |           | trin |           | ross |            |
|        | iling |           | gers |           | Bra  |            |
|        |       |           |      |           | cing |            |
+--------+-------+-----------+------+-----------+------+------------+
| Depth  | Size  | H         | Size | H         | Size | Horizontal |
| of     |       | orizontal |      | orizontal |      |            |
|        | in.   |           | In.  |           | in.  | Spacing    |
| E      | (mm)  | Spacing   | (mm) | Spacing   | (mm) |            |
| xacava |       |           |      |           |      | ft (m)     |
| -tions |       | ft (m)    |      | ft (m)    |      |            |
|        |       |           |      |           |      |            |
| ft (m) |       |           |      |           |      |            |
+--------+-------+-----------+------+-----------+------+------------+
| 5 to   | 2 x 6 | Tight     | 6 x  | 4         | 6 x  | 6          |
| 10     |       |           | 6    |           | 6    |            |
|        | (51 x |           |      | (1.2)     |      | (1.8)      |
| (1.5   | 152)  |           | (152 |           | (152 |            |
| to     |       |           | x    |           | x    |            |
| 3.0)   |       |           | 152) |           | 152) |            |
+--------+-------+-----------+------+-----------+------+------------+
| 10 to  | 2 x 6 | Tight     | 8 x  | 4         | 6 x  | 6          |
| 20     |       |           | 8    |           | 6    |            |
|        | (51 x |           |      | (1.2)     |      | (1.8)      |
| (3.0   | 152)  |           | (203 |           | (152 |            |
| to     |       |           | x    |           | x    |            |
| 6.1)   |       |           | 203) |           | 152) |            |
+--------+-------+-----------+------+-----------+------+------------+

**4. CONDUIT EXCAVATING, GRADING, AND LAYING**

**4.1** Conduit trenches excavated in firm soils should be shored using
2 in. by 6 in. (51 mm by 152 mm) or larger planks. Planks should be
vertically spaced along both sides of trenches and braced using either
jacks or 2 in. by 6 in. (51 mm by 152 mm) braces that are either cleated
or rigidly wedged.

**4.2** Conduit trenches excavated in soils that are susceptible to
cave-ins such as soft, sandy, or loose soils, trenches should be shored
and braced as indicated in Table 6 of this section. For conduit trenches
having widths of 4 ft (1.2 m) or less and excavated in soils likely to
either crack or crumble, trenches should be shored and braced as
indicated in Table 7 of this section. For conduit trenches having widths
greater than 4 ft (1.2 m) and excavated in soils likely to either crack
or crumble, trenches should be shored and braced as indicated in Table 8
of this section.

TABLE 6

Conduit Trench Excavations

Bracing and Sheet Piling

All Trench Widths

Soft, Sandy, or Loose Soils

+--------+--------+-----------+------+-----------+------+-----------+
|        | Sheet  |           | S    |           | C    |           |
|        | Piling |           | trin |           | ross |           |
|        |        |           | gers |           | Bra  |           |
|        |        |           |      |           | cing |           |
+--------+--------+-----------+------+-----------+------+-----------+
| Depth  | Size   | H         | Size | H         | Size | H         |
| of     |        | orizontal |      | orizontal |      | orizontal |
|        | in.    |           | in.  |           | in.  |           |
| Trench | (mm)   | Spacing   | (mm) | Spacing   | (mm) | Spacing   |
|        |        |           |      |           |      |           |
| ft (m) |        | ft (m)    |      | ft (m)    |      | ft (m)    |
+--------+--------+-----------+------+-----------+------+-----------+
| 5 to   | 2 x 6  | Tight     | 6 x  | 4         | 6 x  | 6         |
| 10     |        |           | 6    |           | 6    |           |
|        | (51 x  |           |      | (1.2)     |      | (1.8)     |
| (1.5   | 152)   |           | (152 |           | (152 |           |
| to     |        |           | x    |           | x    |           |
| 3.0)   |        |           | 152) |           | 152) |           |
+--------+--------+-----------+------+-----------+------+-----------+
| 10 to  | 2 x 6  | Tight     | 8 x  | 4         | 6 x  | 6         |
| 20     |        |           | 8    |           | 6    |           |
|        | (51 x  |           |      | (1.2)     |      | (1.8)     |
| (3.0   | 152)   |           | (203 |           | (152 |           |
| to     |        |           | x    |           | x    |           |
| 6.1)   |        |           | 203) |           | 152) |           |
+--------+--------+-----------+------+-----------+------+-----------+

TABLE 7

Conduit Trench Excavations

Bracing and Sheet Piling

Trench Widths of 4 ft (1.2 m) or Less

Cracking or Crumbling Soils

+--------+--------+-----------+------+-----------+------+-----------+
|        | Sheet  |           | S    |           | C    |           |
|        | Piling |           | trin |           | ross |           |
|        |        |           | gers |           | Bra  |           |
|        |        |           |      |           | cing |           |
+--------+--------+-----------+------+-----------+------+-----------+
| Depth  | Size   | H         | Size | H         | Size | H         |
| of     |        | orizontal |      | orizontal |      | orizontal |
|        | in.    |           | in.  |           | in.  |           |
| Trench | (mm)   | Spacing   | (mm) | Spacing   | (mm) | Spacing   |
|        |        |           |      |           |      |           |
| ft (m) |        | ft (m)    |      | ft (m)    |      | ft (m)    |
+--------+--------+-----------+------+-----------+------+-----------+
| 5 to   | 2 x 6  | 3         | 4 x  | 5         | 4 x  | 5         |
| 10     |        |           | 6    |           | 6    |           |
|        | (51 x  | \(1\)     |      | (1.5)     |      | (1.5)     |
| (1.5   | 152)   |           | (102 |           | (102 |           |
| to     |        |           | x    |           | x    |           |
| 3.0)   |        |           | 152) |           | 152) |           |
+--------+--------+-----------+------+-----------+------+-----------+
| 10 to  | 2 x 6  | 2         | 4 x  | 4         | 4 x  | 4         |
| 15     |        |           | 6    |           | 6    |           |
|        | (51 x  | (0.6)     |      | (1.2)     |      | (1.2)     |
| (3.0   | 152)   |           | (102 |           | (102 |           |
| to     |        |           | x    |           | x    |           |
| 4.6)   |        |           | 152) |           | 152) |           |
+--------+--------+-----------+------+-----------+------+-----------+

TABLE 8

Conduit Trench Excavations

Bracing and Sheet Piling

Trench Widths Greater Than 4 ft (1.2 m)

Cracking or Crumbling Soils

+--------+--------+-----------+------+-----------+------+-----------+
|        | Sheet  |           | S    |           | C    |           |
|        | Piling |           | trin |           | ross |           |
|        |        |           | gers |           | Bra  |           |
|        |        |           |      |           | cing |           |
+--------+--------+-----------+------+-----------+------+-----------+
| Depth  | Size   | H         | Size | H         | Size | H         |
| of     |        | orizontal |      | orizontal |      | orizontal |
|        | in.    |           | in.  |           | in.  |           |
| Trench | (mm)   | Spacing   | (mm) | Spacing   | (mm) | Spacing   |
|        |        |           |      |           |      |           |
| ft (m) |        | ft (m)    |      | ft (m)    |      | ft (m)    |
+--------+--------+-----------+------+-----------+------+-----------+
| 5 to   | 2 x 6  | 3         | 4 x  | 4         | 4 x  | 6         |
| 10     |        |           | 6    |           | 6    |           |
|        | (51 x  | \(1\)     |      | (1.2)     |      | (1.8)     |
| (1.5   | 152)   |           | (102 |           | (102 |           |
| to     |        |           | x    |           | x    |           |
| 3.0)   |        |           | 152) |           | 152) |           |
+--------+--------+-----------+------+-----------+------+-----------+
| 10 to  | 2 x 6  | Tight     | 6 x  | 4         | 6 x  | 6         |
| 20     |        |           | 6    |           | 6    |           |
|        | (51 x  |           |      | (1.2)     |      | (1.8)     |
| (3.0   | 152)   |           | (152 |           | (152 |           |
| to     |        |           | x    |           | x    |           |
| 6.1)   |        |           | 152) |           | 152) |           |
+--------+--------+-----------+------+-----------+------+-----------+

**4.3** When excessive water is present in conduit trenches, tongue and
groove sheeting should be considered for use to reduce pumping
requirements.

**4.4** When removing braces from trenches, lower braces should be
removed first. Upper braces should be removed last to provide protection
for construction personnel.

**4.5** When foreign structures are encountered in trenches, it may be
necessary to go to greater depths than would otherwise be required in
order to obtain suitable clearances for conduits. Where this is
impracticable or undesirable, foreign structures may be moved or trench
lines shifted to obtain the required clearances. If foreign structures
must be moved to obtain clearances, companies owning the foreign
structures should be contacted about performing the work.

**4.6** Conduit trenches should cross under gas, steam, or water lines
rather than above them provided, however, that depths of trenches would
not be excessively increased. Conduit trenches paralleling either above
or below gas, steam, or water lines should be avoided, as far as
practicable.

**4.7** Gas and oil lines should be given special attention and
precaution should be taken to guard against fire hazards they present.
Excavations in public streets should always be checked for gas leaks,
even though gas or sewer lines may not be directly encountered. Open
flames of any sort should not be permitted around excavations when gas
odors are detected. Construction personnel should not be allowed to
smoke and precautions should be taken to prevent pedestrians from
throwing lighted products into such excavations. When excavations
involving foreign

structures are undertaken, owners of foreign structures should be
notified so that representatives of foreign structures may be present at
excavations if desired.

**4.8** The minimum separation between electric power conduits and
telecommunications conduits should be as indicated in the latest edition
of the NESC. The minimum separation between foreign pipes such as gas,
water, oil, etc. and telecommunications conduits should be at least 6
in. (152 mm) when crossing such pipes and at least 12 in. (305 mm) when
paralleling such pipes measured from the nearest part of the conduit
structure.

**4.9** Foreign pipes diagonally crossing trenches should be supported
when necessary. Foreign pipes paralleling trenches and either extending
partially into trenches or located within 12 in. (305 mm) of trenches
should be laterally braced by shoring, except when sheeting materials
used to support trench walls provide adequate bracing for pipes.

**4.10** Trench beds should be leveled to provide even bases before
installing conduits. In some cases, sand or screened earth may be
required to be placed in trench beds to provide conduits with stable
bases. In other cases, concrete may be required to be placed in trench
beds to provide conduits with stable bases. The types of bases to be
placed in trench beds to provide adequate conduit support should be
based on the plans and specifications.

**4.11** When trenches containing large volumes of water will not permit
installation or jointing of conduits, water in those trenches should be
disposed of by placing layers of crushed stone in trench beds to allow
the water to drain to sumps while conduits are being installed. Layers
of earth or sand over stone should be applied prior to installation of
conduits. Where conditions exist that water in trenches can not be
adequately removed, systems of well-points paralleling trenches to lower
levels of ground water to levels below bottoms of excavations may have
to be employed.

**4.12** Conduit entrances at opposite ends of UCVs should be at the
same levels and in the same positions with respect to side walls to
facilitate conduit rodding, cable placing, and splicing. Conduit
trenches should be graded to conduit entrances of UCVs. Locations at
which trench grades to UCV entrances should begin to change will depend
on the following:

a\. Types of conduit configurations;

b\. Usage of mitered conduits; or

c\. Employment of splayed conduits.

**4.13** Conduit trenches should be graded in areas where subfreezing
ground conditions are expected to penetrate to conduit installation
depths. In those areas, trench grades should fall 3 in. (76 mm) in 100
ft (30 m) for conduits toward lower UCVs or from high points in conduit
sections toward both UCVs.

**4.14** Installation of conduits; spacer supports; jointing of conduits
with associated fittings for bends, sweeps, bell ends, adapters for
jointing different types of conduits; and terminations should be
performed in accordance with conduit manufacturers' installation
practices.

**5.** **BACKFILLING OF CONDUIT TRENCHES AND CONDUIT SEALING**

**5.1** Backfilling material installed next to conduits should be free
of stones and other materials, which could damage either conduits or
conduit joints. Backfilling material should not contain large boulders.
Tamping of backfill at sides of conduits should be performed with
extreme care to avoid either damage to joints or shifting of conduit
configurations. The use of spacer supports placed at distances
recommended by the conduit manufacturer in conduit configurations should
aid in the prevention of shifting conduit configurations during tamping
operations. Backfilling and tamping alongside conduits should be
performed in 2 in. (51 mm) thick layers until level with top of conduit
configurations. Backfilling around conduits jointed with mortar bandages
should proceed as soon as joints are completed. Troweled joints should
be allowed to set-up for 24 hours before backfilling. Conduit trenches
with concrete top protection or encasement should be backfilled as soon
as possible.

**5.2** Backfill above conduits should be thoroughly tamped in 6 in.
(152 mm) layers. In most cases mechanically tamped backfill will provide
better compaction than hand-tamped backfill. Where large amounts of
backfilling and tamping are to be performed, backfilling and tamping
machines should be used. To avoid damage to conduits, mechanical tampers
should not be used until conduit configurations have been covered with
at least 12 in. (305 mm) of hand-tamped backfill. In sandy soils, water
may be used to provide satisfactory compaction when backfill is
installed in

6 in. (152 mm) layers and flooded. Where cinders form part of the soil,
clean earth should be used as backfill adjacent to conduits and soils
containing the cinders should not be replaced until conduits have been
covered with at least 6 in. (152 mm) of cinder-free soil. In cases where
soils are composed of mainly cinders, concrete encasement of conduits
should be considered.

**5.3** Test mandrels which are 0.25 in (6 mm) smaller in diameters than
the inside diameters of conduits should be pulled through all single
conduits and through two diagonally opposite conduits in multi-conduit
configurations to ensure proper alignments. The pulling of the test
mandrels through the conduits should be performed after backfilling but
prior to the replacement of any grass, sod, repaving, etc. In addition,
all conduits should be cleaned of loose materials such as concrete, mud,
dirt, stones, etc.

**5.4** Paving or temporary repaving over conduit trenches should be
performed in accordance with local, county and/or state regulations. The
local, county and/or state regulations regarding paving or repaving
should be included as of part of the RUS Telecommunications System
Construction Contract

(RUS Form 515).

**5.5** All surplus matter excavated in conjunction with backfilling
operations should be removed so as not to obstruct traffic. Where space
is restricted, surplus matter should be removed at the time of
excavating. If possible, small quantities of excavated materials should
remain at construction sites to be used later for filling in temporarily
repaved trenches where settlement occurs.

**5.6** On public rights-of-way (R/W) or lands where construction of
conduit trenches require removal of sod or top soil, trench surfaces
should be restored to their original appearances by resurfacing trenches
with the original sod or top soil removed during construction
operations.

**5.7** When the construction projects have been completed, all surplus
materials and debris should be removed from construction sites.

**5.8** Conduit ends should be sealed to prevent the entrance of foreign
matter and to prevent the entrance of water or gas into UCVs or
buildings. Conduits should be sealed in accordance with conduit
manufacturer's recommendations. All conduits entering central offices or
other buildings should be sealed at all times except when placing
cables. If construction work extends over several days, conduits should
be temporarily sealed at night, but permanently sealed upon completion
of construction.

**6. SUBSIDIARY CONDUIT INSTALLATION**

**6.1** The term "subsidiary conduits" is commonly used to define any
conduits branching off from main conduit runs. Subsidiary conduits
should be installed using the same construction and installation
practices as defined for main line conduits.

**6.2** Figure 3 of this bulletin indicates the typical installation
procedures for subsidiary conduits when used as pole riser conduits.

**6.3** Subsidiary conduits entering buildings should be placed before
buildings are erected if possible. In this situation, suitable sleeves
or stub outs can be inserted in building walls or floors at the time of
construction. If subsidiary conduits are placed after building
construction, entrances should be installed through building walls or
floors at points not vital to support the buildings.

**7. CONCRETE AND AGGREGATE FOR POURED-IN-PLACE UCVS AND FOR**

**CONDUIT PROTECTION AND ENCASEMENT**

**7.1** Concrete mixtures containing Portland cement should be used in
the construction of all poured-in-place UCVs. Concrete mixtures
containing Portland cement should also be used for either top
protection, base stability, or encasement of conduits when required.

**7.2** Basically there are three types of Portland cement, which may be
used, in concrete construction of underground plant. The three types are
as follows:

a\. Normal;

b\. High early strength; and

c\. Sulfate-resisting.

**7.3** Normal Portland cement should be used for all concrete
construction unless otherwise indicated on the construction drawings by
the resident. High early strength Portland cement should be used for
concrete construction when it is necessary to remove forms and open
structures to traffic at earlier dates after concrete has been placed.
High early strength Portland cement may also be used for concrete
construction during low temperatures. Sulfate-resisting Portland cement
has the characteristics to withstand exposure to severe alkali
conditions and has the same setting characteristics as normal Portland
cement. Therefore, sulfate-resisting Portland cement should only be used
for concrete construction when designated by the resident.

**7.4** There are eight classes of concrete that may be used in
underground plant construction. The eight concrete classes and their
suggested usage for underground plant concrete construction are listed
below:

a\. Class 1A - For poured-in-place UCVs where concrete is

compacted by hand tamping;

b\. Class 1B - For poured-in-place UCVs where concrete is

compacted by mechanical vibration, for replacing

concrete pavements, and for poured-in-place UCV floors

where compaction is performed by hand tamping;

c\. Class 1C - For poured-in-place UCVs where concrete is

compacted by hand tamping and where high early strength

Portland cement is required and for low temperature

construction;

d\. Class 1D - For poured-in-place UCVs where concrete is

compacted by mechanical vibration and where high early

strength Portland cement is required, for concrete

pavement replacement where high early strength Portland

strength is required, and for poured-in-place UCV

floors where compaction is performed by hand tamping and

where high early strength Portland cement is required;

e\. Class 2A - For conduit base or top protection;

f\. Class 2B - For conduit encasement, particularly where it

is necessary to work the concrete between and around

closely spaced units of various types of single conduit;

g\. Class 2C - For replacement of concrete bases for

asphalt, brick, or granite pavements; and

h\. Class 2D - As a substitute for Class 2C concrete where

high early strength Portland cement is required or for

low temperature construction.

**7.5** Bags of cement should be kept dry at all times to prevent
deterioration of the cement. Bags should be stored in either buildings
or on raised platforms that are covered with tarps.

**7.6** Cement containing lumps that can not be pulverized by hand
should not be used in concrete construction operations. The presence of
such lumps indicates that the cement has absorbed moisture, which is an
indication that the cement has deteriorated.

**7.7** All Class 1 grades of concrete should have compressive strengths
equal to or greater than 3600 pounds per square inch (psi) \[25
megapascals (MPa)\] at 28 days when made with normal or
sulfate-resisting Portland cement and at 7 days when made with high
early strength Portland cement.

**7.8** All Class 2 grades of concrete should have compressive strengths
equal to or greater than 2500 psi (17 MPa) at 28 days when made with
normal or sulfate-resisting Portland cement and at 7 days when made with
high early strength Portland cement.

**7.9** Water contained in aggregates should be considered as part of
the water used in mixing the concrete. Therefore, the quantity of water
added to the concrete mixture should be adjusted so that the total
quantity of water in the concrete would not exceed the quantities shown
in Table 9 of this section.

TABLE 9

Trial Mixes for Cubic Yards of Concrete

<table>
<colgroup>
<col style="width: 8%" />
<col style="width: 12%" />
<col style="width: 11%" />
<col style="width: 9%" />
<col style="width: 9%" />
<col style="width: 0%" />
<col style="width: 9%" />
<col style="width: 9%" />
<col style="width: 0%" />
<col style="width: 9%" />
<col style="width: 10%" />
<col style="width: 9%" />
</colgroup>
<tbody>
<tr class="odd">
<td colspan="2">Concrete Class</td>
<td>1A</td>
<td>1B</td>
<td>1C</td>
<td colspan="2">1D</td>
<td>2A</td>
<td colspan="2">2B</td>
<td>2C</td>
<td>2D</td>
</tr>
<tr class="even">
<td colspan="2">Cement Type</td>
<td>N or S*</td>
<td>N or S*</td>
<td>HES**</td>
<td colspan="2">HES**</td>
<td>N or S*</td>
<td colspan="2">N or S*</td>
<td>N or S*</td>
<td>HES**</td>
</tr>
<tr class="odd">
<td colspan="2">Tamping Requirement</td>
<td>Hand</td>
<td>Mech.</td>
<td>Hand</td>
<td colspan="2">Mech.</td>
<td>Hand</td>
<td colspan="2">Hand</td>
<td>Hand</td>
<td>Hand</td>
</tr>
<tr class="even">
<td colspan="2">Slump Range in.</td>
<td>4 – 6</td>
<td>2 – 4</td>
<td>4 – 6</td>
<td colspan="2">2 – 4</td>
<td>1.5 – 3</td>
<td colspan="2">6 – 8</td>
<td>2 – 4</td>
<td>2 – 4</td>
</tr>
<tr class="odd">
<td></td>
<td><p>Cement</p>
<p>(Sacks)</p></td>
<td>6.5</td>
<td>6.25</td>
<td colspan="2">6.5</td>
<td>6.25</td>
<td colspan="2">4.75</td>
<td>5.5</td>
<td>4.5</td>
<td>4.5</td>
</tr>
<tr class="even">
<td></td>
<td><p>Water</p>
<p>Gallons</p></td>
<td>30.5</td>
<td>28.5</td>
<td colspan="2">30.5</td>
<td>28.5</td>
<td colspan="2">26.5</td>
<td>32</td>
<td>25.75</td>
<td>25.75</td>
</tr>
<tr class="odd">
<td>With Gravel</td>
<td><p>Sand</p>
<p>Pounds (lbs)</p>
<p>Fine Aggregate</p></td>
<td>1420</td>
<td>1440</td>
<td colspan="2">1420</td>
<td>1440</td>
<td colspan="2">1510</td>
<td>1440</td>
<td>1290</td>
<td>1290</td>
</tr>
<tr class="even">
<td></td>
<td><p>Sand Cubic</p>
<p>Yards Fine Aggregate</p></td>
<td>0.59</td>
<td>0.60</td>
<td colspan="2">0.59</td>
<td>0.60</td>
<td colspan="2">0.63</td>
<td>0.60</td>
<td>0.54</td>
<td>0.54</td>
</tr>
<tr class="odd">
<td></td>
<td><p>Gravel</p>
<p>lbs Coarse Aggregate</p></td>
<td>1750</td>
<td>1780</td>
<td colspan="2">1750</td>
<td>1780</td>
<td colspan="2">1860</td>
<td>1770</td>
<td>2130</td>
<td>2130</td>
</tr>
<tr class="even">
<td></td>
<td>Gravel Cubic Yards Coarse Aggregate</td>
<td>0.65</td>
<td>0.67</td>
<td colspan="2">0.65</td>
<td>0.67</td>
<td colspan="2">0.70</td>
<td>0.66</td>
<td>0.80</td>
<td>0.80</td>
</tr>
<tr class="odd">
<td></td>
<td><p>Cement</p>
<p>(Sacks)</p></td>
<td>7</td>
<td>6.75</td>
<td colspan="2">7</td>
<td>6.75</td>
<td colspan="2">5.25</td>
<td>6</td>
<td>5</td>
<td>5</td>
</tr>
<tr class="even">
<td></td>
<td><p>Water</p>
<p>Gallons</p></td>
<td>33.25</td>
<td>31</td>
<td colspan="2">33.25</td>
<td>31</td>
<td colspan="2">29.5</td>
<td>35</td>
<td>28</td>
<td>28</td>
</tr>
<tr class="odd">
<td>With Stone</td>
<td><p>Sand lbs</p>
<p>Fine Aggregate</p></td>
<td>1510</td>
<td>1570</td>
<td colspan="2">1510</td>
<td>1570</td>
<td colspan="2">1620</td>
<td>1540</td>
<td>1420</td>
<td>1420</td>
</tr>
<tr class="even">
<td></td>
<td><p>Sand</p>
<p>Cubic Yards Fine Aggregate</p></td>
<td>0.63</td>
<td>0.65</td>
<td colspan="2">0.63</td>
<td>0.65</td>
<td colspan="2">0.68</td>
<td>0.64</td>
<td>0.59</td>
<td>0.59</td>
</tr>
<tr class="odd">
<td></td>
<td><p>Gravel</p>
<p>lbs Coarse Aggregate</p></td>
<td>1530</td>
<td>1560</td>
<td colspan="2">1530</td>
<td>1560</td>
<td colspan="2">1640</td>
<td>1560</td>
<td>1910</td>
<td>1910</td>
</tr>
<tr class="even">
<td></td>
<td>Gravel Cubic Yards Coarse Aggregate</td>
<td>0.57</td>
<td>0.58</td>
<td colspan="2">0.57</td>
<td>0.58</td>
<td colspan="2">0.61</td>
<td>0.58</td>
<td>0.71</td>
<td>0.71</td>
</tr>
</tbody>
</table>

Notes:

1\. \*N -- Normal or S -- Sulfate Resisting Cement.

2\. \*\*HES -- High Early Strength Cement.

3.  To convert inches (in.) to millimeters (mm)

> multiply by 25.4.

4.  To convert gallons to cubic meters (m^3^)

> multiply by 0.003785.
>
> 5\. To convert pounds (lbs) to kilograms (kg)

multiply by 0.4535.

6\. To convert cubic yards to cubic meters

multiply by 0.7645.

**7.10** Watertight concrete uses aggregates that are completely coated
with cement paste that resists passage of water. Water leakage through
concrete is usually through the cement paste. Water leakage may be
prevented by having a sufficient quantity of cement paste to coat all
aggregate particles and to fill all voids between aggregate particles.
Class 1 grades of concrete have water-cement ratios that should produce
watertight concrete. To ensure that concrete would be watertight, water
should be prevented from flowing through or over freshly placed concrete
to eliminate the washing away of the cement paste. Concrete mixtures
using additives to produce watertight concrete should not be used in
underground plant construction. The use of watertight concrete for
underground plant construction should be indicated on the construction
drawings by the resident.

**7.11** Aggregates used in the preparation of concrete have an
important bearing on the quality of finished concrete. Fine aggregates
should consist of either natural sand, sand prepared from stone, blast
furnace slag, or gravel. Coarse aggregates should consist of crushed
stone, gravel, blast furnace slag, or other inert materials of similar
characteristics, or combinations of the above materials having hard,
strong, durable pieces and free from adherent coatings. Aggregates used
in concrete should not contain cinders.

**7.12** Fine aggregates for concrete should be graded from coarse to
fine by means of sieves as indicated in Table 10 of this section. In
coarse aggregates, the amounts of foreign substances such as soft
fragments, coal, clay, shale, or other materials detrimental to the
concrete quality should not exceed 5 percent of the total weight of
coarse aggregates. Table 11 of this section indicates the sizes, grading
sieves, and intended usage of coarse aggregates that should be used in
concrete construction operations of underground plant.

TABLE 10

Fine Aggregate Grading

+-------------------------------------+--------------------------------+
| Sieve Sizes                         | Grading                        |
|                                     |                                |
|                                     | Percent By Weight              |
+-------------------------------------+--------------------------------+
| Passing a 3/8 in. (9.5 mm)          | 100                            |
+-------------------------------------+--------------------------------+
| Passing a No. 4                     | 95 to 100                      |
+-------------------------------------+--------------------------------+
| Passing a No. 16                    | 45 to 80                       |
+-------------------------------------+--------------------------------+
| Passing a No. 50                    | 5 to 30                        |
+-------------------------------------+--------------------------------+
| Passing a No. 100                   | 0 to 8                         |
+-------------------------------------+--------------------------------+

TABLE 11

Coarse Aggregates

Usage, Sieve Sizes, and Aggregate Sizes

+-----------------+-----------------+-----------------+-----------------+
| Intended Use    | Concrete Class  | Sieve Size      | Aggregate Size  |
|                 |                 |                 |                 |
|                 |                 | Minimum         | Maximum         |
|                 |                 |                 |                 |
|                 |                 |                 | in. (mm)        |
+-----------------+-----------------+-----------------+-----------------+
| Conduit         | 2A              | No. 4           | 0.75 (19)       |
| Protection      |                 |                 |                 |
+-----------------+-----------------+-----------------+-----------------+
| Conduit         | 2B              | No. 4           | 0.5 (13)        |
| Encasement      |                 |                 |                 |
+-----------------+-----------------+-----------------+-----------------+
| Pavement        | 2C and 2D       | No. 4           | 1.5 (38)        |
| Replacement     |                 |                 |                 |
+-----------------+-----------------+-----------------+-----------------+

**7.13** Aggregates should be stored separately to prevent mixture with
other types of aggregates until aggregates are used and to prevent
inclusion of foreign materials.

**7.14** Concrete construction during cold weather may be performed
where suitable precautions are observed. In early winter, when freezing
temperatures occur only at night, finished concrete should be protected
against freezing. When freezing temperatures constantly persist, it may
be necessary to heat the water and aggregates during concrete mixing
operation in addition to protecting the finished concrete from freezing.
With approval of the resident, concrete construction may be performed at
temperatures below 20F (-6.7C) when the above mentioned precautions are
observed and high early strength Portland cement is substituted for
normal Portland cement in the concrete mixture. Earth surrounding the
conduit installation also serves to protect the concrete from freezing.
Therefore, conduit trenches constructed during cold weather should be
immediately backfilled with material that is not frozen after conduit
installations. Concrete, which has been damaged by freezing
temperatures, should be replaced with freshly mixed concrete.

**7.15** In localities where ready-mix concrete is available, the use of
ready-mix concrete should be considered for the concrete construction
operation because ready-mix concrete affords convenience of delivery and
uniform concrete quality at reasonable costs.

**8. CONDUIT RODDING AND CLEANING**

**8.1** Before installation of underground cables, conduits should be
rodded to determine if conduits are free of foreign obstructions, which
may prevent placement of cables in conduits. Rodding consists of pulling
a test mandrel through the conduit section between UCVs to remove the
obstruction. The diameter of the test mandrel should be equal to or
slightly larger than the diameter of either the cable or the pulling
eye, whichever is larger.

**8.2** Conduits suspected or found to contain particles of earth, sand,
gravel, etc. should be cleaned by pulling a stiff bristled wire brush
through the conduits.

**8.3** Conduits suspected or found to be obstructed with foreign
materials which can not be removed by rodding or cleaning should be
immediately reported to the resident. The resident should then determine
what appropriate action should be taken to alleviate the obstructions.

**9. CABLE LOCATION AND CONDUIT SELECTION**

**9.1** Filled copper cables should be placed relative to cable numbers,
pair counts, cable sizes, cutting lengths, and conductor gauges in
accordance with construction drawings. Filled fiber optic cables should
be placed relative to cable numbers, fiber counts, cable sizes, cutting
lengths, and optical fiber types in accordance with construction
drawings.

**9.2** Records of copper or fiber optic cable footage installed and
footage of copper or fiber optic cables remaining on reels after cutting
lengths have been removed should be maintained for each reel of
underground copper or fiber optic cable used on the construction
project.

**9.3** Each copper or fiber optic cable reel should have a tag fixed to
the outside of each flange indicating the copper or fiber optic cable
footage remaining on the reel. The tag should be updated immediately
after a cut length is removed from the reel.

**9.4** Conduit assignments for each individual copper or fiber optic
cable for any conduit section should be in accordance with the
construction drawings. Copper or fiber optic cables should be racked in
UCVs or buildings in accordance with the construction drawings. Figure 4
of this bulletin provides an example of racking underground cable and
splice cases in UCVs.

**10. CABLE REEL AND APPARATUS SET-UP**

**10.1** Cable reels should be inspected for flange protrusions, which
could damage cable sheaths. Construction areas should be inspected to
determine if any obstructions are present that could interfere with
unwinding of cables.

**10.2** When cable reels are required to be moved to different
locations, cable reels should be rolled in the direction indicated by
the arrows painted on the reel flanges. Cable reels should not be
permitted to tilt. Where uneven ground conditions exist that may cause
reels to tilt, heavy planks or equivalent materials should be used as
runways for moving reels to avoid tilting of reels. Where it is
necessary to move cable reels with construction trucks, construction
truck (CT) slings or equivalents should be used.

**10.3** In conduit sections containing curves, cable reels should be
set-up at UCVs near the curves unless not permitted by traffic or other
conditions.

**10.4** Cable reels should be set-up on the same sides of UCVs as
conduit sections in which cables are to be placed. Reels should be
leveled and aligned with conduit sections to prevent twisting of cables
during installation into conduits. Cables should be pulled into conduits
from tops of reels in long smooth bends. Cables should not be pulled
into conduits from bottoms of reels.

**10.5** Cables should be removed from reels by manually rotating the
reels. To eliminate cable binding during removal from reels, adjacent
cable layers on reels should not be allowed to adhere to one another.

**11. PULLING LINES AND ATTACHMENTS**

**11.1** Pulling lines used in cable placing operations should be in
good condition.

**11.2** Markers should be placed on pulling lines 20 ft (6.0 m) from
cable ends to indicate when cables are about to enter UCVs.

**11.3** Pulling lines should be attached to factory installed pulling
eyes as shown in Sketch A of Figure 5 of this bulletin. Pulling lines
should be attached to cable grips as shown in Sketch B of Figure 5 of
this bulletin. Rings to prevent grips from slipping should not be beaten
into cable sheaths. Swivels selected for use should be able to withstand
maximum pulling tensions and still allow pivoting about their axis.

**12. CABLE FEEDING AND PULLING**

**12.1** Cable feed guides of suitable dimensions should be used between
cable reels and conduit faces to protect cables and guide cables into
conduits as cables are payed-off reels. Bend radii of feed guides for
filled copper cables should not be less than 10 times the outside
diameters of cables. Bend radii of feed guides for filled fiber optic
cables should be in accordance with fiber optic cable manufacturers'
recommendations.

**12.2** Before cable placing operations begin, equipment should be
checked to ensure that equipment is properly set-up to ensure that
cables can be placed in conduit sections between UCVs in one operation
without interruptions. Tension should be applied to both cable reels and
pulling lines at the start of cable placing operations. Excessive slack
and twisting of pulling lines should be held to a minimum at the start
of cable placing operations to avoid the possibility of connecting links
twisting and catching in conduits. As far as possible, cables should be
placed without stopping until the required cable amounts have been
installed in UCVs. Pulling speeds for filled copper cable installations
should not exceed 80 to 100 ft/minute (ft/min) (24 to 30 m/min). Pulling
speeds for filled fiber optic cables should be in accordance with cable
manufacturers' recommendations.

**12.3** Mechanical stresses applied to cables during installations
should be held to absolute minimums to avoid excessive twisting,
stretching, or flexing of cables. Excessive twisting, stretching, or
flexing of cables during installations can result in either physical
damage to cable sheaths or deterioration of electrical or optical
properties of filled copper or fiber optic cables, respectively.
Therefore mechanical stresses applied to cables during installations
should not exceed cable manufacturers' recommendations.

**12.4** Cables should be lubricated with lubricants that are compatible
with cable jacket materials as cables are payed-off reels into cable
feed tubes. Cable lubricators (funnels) should be placed around cables
in front of cable feed tubes to facilitate proper lubrication of cables.
Lubricants used in cable placing operations should be in accordance with
cable manufacturer's recommendations. [Soap lubricants or lubricants
containing soap should not be used]{.underline}.

**12.5** The quantities of cable lubricants that should be used in cable
placing operations should be in accordance with cable manufacturers'
recommendations. Lubrication of cables should not be necessary for
conduit sections that are less than or equal to 300 ft (90 m) provided
conduit sections are free of sharp bends.

**12.6** After cables have been installed and before leaving UCVs,
exposed cables in UCVs should be cleaned of lubricants using dry rags.

**12.7** Careful attention should be paid to signals from installation
crews as cables are being placed so that placing may be stopped
instantly to avoid damage to cables. When placing operations are stopped
between UCVs, operators should not release tension on winches unless
directed by the resident. In restarting placing operations, inertia of
cables should be overcome by gradually increasing the tension in steps a
few seconds apart until cables are again in full motion.

**12.8** Leading ends of cables at intermediate UCVs should be guided
into conduits and feeder tubes placed around cables to prevent cables
from rubbing on conduit edges. To ensure that pressure is maintained on
sealing gaskets of factory installed pulling eyes at intermediate UCVs,
pulling eye nuts should be retightened at each intermediate UCV.

**12.9** Sufficient lengths of cables should be left in each UCV to
properly rack and splice cables in accordance with construction
drawings. The amount of cable slack left in each UCV should be indicated
on the construction drawings.

**12.10** After cables have been installed in UCVs, cable ends in all
UCVs should be temporarily secured to cable racks to prevent damage.
Bending of cables in UCVs should be accomplished in a manner to avoid
damage to cables. Cable slack left in UCVs should be looped around UCVs
in long sweeping bends and tied securely in locations where cables would
not obstruct UCV working areas. Cable ends should be placed near UCV
roofs.

**12.11** After cables have been installed, copper cables should be
identified on ends of splices with tags indicating cable numbers, pair
counts, sizes, gauges, and cut lengths. Fiber optic cables should be
identified on ends of splices with tags indicating cable numbers, number
of fibers, fiber types, and cut lengths.

**13. PULLING CABLES INTO SUBSIDIARY CONDUITS**

**13.1** When installing cables in subsidiary conduits extending from
UCVs, service UCVs or vaults to pole risers, or buildings, cable reels
should be located at the ends of the conduits nearest the bends. Cables
should be fed in long smooth curves rather than pulled upward around the
bends from the opposite ends.

**13.2** Due to the number of bends usually encountered in subsidiary
conduits, cable lubricants should be used to facilitate placement of
cables regardless of conduit lengths.

**13.3** Sufficient lengths of cables should left at ends of conduits to
permit setting-up and splicing operations. Cables should be lashed
temporarily to poles or walls to insure that cables do not interfere
with other activities, become safety hazards in work areas, or come in
contact with electrical power services.

**14. SAFETY PRECAUTIONS**

**14.1** Open UCVs should be guarded at all times with either UCV guards
or barricades. These and other warning devices should be set up at UCVs
before removal of UCV covers.

**14.2** During construction of underground plant, warning lights should
be placed between sunset and sunrise and when vision is impaired by fog,
haze, etc. Warning lights should be placed in accordance with local,
State, and/or Federal ordinances.

**14.3** Flames, torches, lit tobacco products, etc. should not be
brought near open UCVS, into covers or tents over UCV openings, or into
UCVs until tests for combustible gases indicate that no such gases are
present in the UCVs.

**14.4** When lighting and heating equipment are to be used in UCVs,
only lighting and heating equipment designated for use in UCVs should be
used. Connection and disconnection of lighting and heating equipment
should be performed outside of UCVs.

**14.5** UCVs opened for the first time during the day or reopened after
having been closed for any length of time should be tested for the
presence of combustible gases. Additional tests should be performed at
the start of each work shift change and at intervals not to exceed two
hours during work shifts. UCVs covered with tents or tarpaulins should
be tested for combustible gases at intervals not to exceed one hour.
UCVs should also be tested for combustible gases after removal of
conduit plugs, which could possibly have permitted the flow of gases
into UCVs. Where gases are detected or suspected, UCVs should be
ventilated using forced fresh air equipment in accordance with the
manufacturer's instructions.

**14.6** Adequate communications should be established between cable
feeding locations and other pulling equipment locations prior to
starting of pulling operations.

**14.7** Construction materials and tools should be arranged in such
manners to avoid the possibility of such materials and tools falling
into UCVs or unnecessarily interfering with pedestrian or vehicular
traffic.

**14.8** Caution should be exercised when entering or exiting UCVs,
particularly UCVs located on traveled thoroughfares. Ladders should be
for entering and exiting UCVs. Entering and exiting UCVs should be
performed facing oncoming traffic. Hands should be kept free of
materials or tools when ascending or descending ladders.

**15. HANDLING AND CARE OF MATERIALS DURING CONSTRUCTION**

**15.1** Extreme care should be exercised in handling materials during
the construction process. Underground cable pulling operations should be
inspected at all times to ensure that maximum cable pulling tensions are
not exceeded. Under no circumstances should maximum pulling tensions be
allowed to develop in the cables during pulling operations. Exceeding
maximum cable pulling tensions could result in damages to cables.
Whenever pulling operations are stopped, cables should remain under
tension. When restarting pulling operations, tensions on cables should
be gradually increased in steps of a few seconds apart until cables are
once again in motion.

**15.2** Cable reels delivered to work locations but not set up
immediately for pulling operations should be securely blocked or secured
to substantial supports to prevent rolling or movement of reels. Cable
reels used in pulling operations should not be left on grades or in
traffic lanes. When reels are required to be left on grades, reels
should be turned against curbs and blocked to prevent rolling of reels.

**15.3** Cable reels stored overnight on streets or highways should be
marked in accordance with local, State, or Federal regulations. If no
local, State, or Federal marking regulations exist for storing reels
overnight on streets or highways, reels should be barricaded and lit
with flashing lights or red lanterns not later than one-half hour before
sunset.

**15.4** Care should be exercised to prevent damage to exposed cables
during the construction period. Construction work should be scheduled to
keep such exposure to a minimum. Cables left exposed are susceptible to
damage. Cables left exposed are also considered hazards to vehicles,
pedestrians, or animals.

**15.5** Copper and fiber optic cables in UCVs should be racked in
accordance with the construction drawings and spliced in underground
filled splice cases as soon as practicable. The installation work should
be completed within one week after the cables have been installed.

**15.6** Underground plant connections using dissimilar metals should be
avoided to eliminate the possibility of galvanic corrosion. Therefore
underground plant connections should be made using only tinned coated
metals.

**15.7** When working in UCVs care should be exercised to prevent damage
to cables in setting up pulling apparatus or while using tools of any
kind. Cables, splice cases, etc. should not be used as steps for
entering or exiting UCVs.

**16 REPAIR OF CABLES DAMAGED DURING CONSTRUCTION**

**16.1** Minor damage to the outer jackets, where the shields or armors
of the cables have not been bent, abraded, or penetrated should be
repaired in accordance with Bulletin 1753F-401(PC-2), RUS Standard for
Splicing Copper and Fiber Optic Cables.

**16.2** Cables found to be damaged after installation should be
repaired. If the damage is considered minor, the damage should be
repaired in accordance with Bulletin 1753F-401(PC-2), RUS Standard for
Splicing Copper and Fiber Optic Cables. If the damage is considered
major, the damage should be repaired either by replacing the damaged
sections with new cables spliced to the undamaged sections of the cable
or repaired in accordance with the method specified in the contract.

**17. PREPARATION FOR SPLICING OR TERMINATION**

**17.1** Underground filled copper cables should be spliced in
accordance with Bulletin 1753F-401(PC-2), RUS Standard for Splicing
Copper and Fiber Optic Cables, and enclosed in RUS accepted or
technically accepted underground filled splice cases.

**17.2** Underground filled fiber optic cables should be spliced in
accordance with Bulletin 1753F-401(PC-2), RUS Standard for Splicing
Copper and Fiber Optic Cables, and enclosed in RUS accepted or
technically accepted filled fiber optic splice cases.

**18. INSTALLATION PROCEDURES FOR FILLED CABLES IN COLD WEATHER**

**18.1** Flexibility of filled copper and fiber optic cables should not
be a problem at normal operating temperatures. However, flexibility may
be affected when cables are exposed to lower temperatures. The
flexibility of filled copper and fiber optic cables could be sharply
reduced at temperatures below 40°F (4.4°C). At temperatures below 40°F
(4.4°C), almost twice the force may be needed to bend the filled copper
and fiber optic cables. Filled copper and fiber optic cables should be
inspected each morning to determine if the cables are flexible enough
for underground placement when night time temperatures drop below 30°F
(-1.1°C). When filled copper or fiber optic cables have been stored
outdoors and subjected to cold nights, considerable time may be lost
each morning waiting for the cables to warm up even though the day time
temperature may be above 40°F (4.4°C). During the spring and fall of the
year, filled copper or fiber optic cables may be stored in heated
warehouses prior to placement in underground conduits. This storage in
heated warehouses allows the filled copper or fiber optic cables to be
transported to the project site as needed and installed while the cables
are still flexible.

**18.2** Some filling compounds used in the cores of filled copper
cables may be stiff as the temperature decreases making it difficult to
separate the cable pairs. In general, filled copper cables installations
below 40°F (4.4°C) could be slow, difficult, and possibly even halted
unless special precautions are taken to offset the effects of the lower
temperatures.

**18.3** Filling compounds used in loose tube buffers of filled fiber
optic cables should not become stiff as the temperature decreases. This
should allow the optical fibers to be easily separated at low
temperatures.

**18.4** As mentioned in paragraph 18.2 of this section, the copper
pairs may be difficult to separate as the temperature decreases. At
temperatures as low as 20°F (-6.7°C), copper pairs may be separated by
flexing the free ends of the cable cores and separating a few pairs at a
time. It is also interesting to note that filling compounds at a
temperature of 20°F (-6.7°C) are more user friendly to work with than at
elevated temperatures. Consequently, the copper cable pairs may be
spliced without wiping the pairs free of filling compound.

**19. ASSEMBLY UNITS AND ACCEPTANCE TESTS**

**19.1** Detailed descriptions of all standard underground plant
assembly units are given in RUS Bulletin 1753F-151, Specifications and
Drawings for Construction of Underground Plant, RUS Form 515b.

**19.2** Where standard underground plant assembly units are
insufficient to provide for unique underground plant construction
requirements, detailed "nonstandard assembly units" should be

created to meet those requirements. The underground plant nonstandard
assembly units should be approved by RUS prior to the bidding of the
project.

**19.3** After installation, underground copper and fiber optic cables
should be tested in accordance with RUS Bulletin 1753F-201(PC-4), RUS
Standard for Acceptance Tests and Measurements of Telecommunications
Plant, and the RUS Form 515 Contract.