Conductors

MIL-HDBK-1004/2A

Table 3

Wood Pole Sizes for Single Pole Transformer Installations

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MAXIMUM TRANSFORMER RATING (KVA)

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POLE

ONE

BANK OF THREE

ONE

MINIMUM CLASS

SINGLE-PHASE

SINGLE-PHASE (CLUSTER MOUNTED)

THREE-PHASE

--------------------------------------------------------------------------

5

--

4

15

--

4

25

--

3

37-1/2

--

15

3

--

3-15

30

2

50

3-25

45

2

75

3-37-1/2

75

1

100

3-50

112-1/2

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2.2.3

Conductors. Refer to Fink and Beaty, Standard Handbook for

Electrical Engineers for conductor characteristics.

2.2.3.1 Size Limitations. Normally limit the use of pole line conductors in

accordance with Table 4, except for primary wires which usually should be not

less than No. 6 AWG (13.3 square mm) copper or No. 2 AWG (33.6 square mm)

aluminum. The range of conductors in Table 4 gives the most economical system

from the installation, operational, and maintenance points of view. Special

instances may require larger conductors. In all cases be sure that the type

and size of conductors used has adequate strength for span lengths and loading

conditions. Select conductor sizes to provide required minimum strengths in

accordance with loading requirements of ANSI C2 for areas in the United States

and in accordance with facility loading requirements for areas outside the

United States.

2.2.3.2 Normal Primary Lines. Normally, specify bare conductors for primary

lines stranded or solid construction as suitable to the size and composition

as follows:

a)

copper conductor, (Cu);

b)

aluminum-alloy conductor, (AAC);

c)

aluminum conductor, steel reinforced (ACSR); and

d)

high-strength all-aluminum alloy conductor (AAAC).

2.2.3.3 Tropical and Semitropical Locations. For tropical and semitropical

locations, use AAAC rather than ACSR because the steel strands of the ACSR are

susceptible to corrosion.

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