TM
5-811-1/AFJMAN
32-1080
b. Lengths and strengths. Pole lengths will be
by the Host Command coordinated with the Re-
selected conservatively, making allowance for the
quiring Command (HOST/REQ CMD).
(4) Aluminum conductors shall be terminated
installation of communication lines and the re-
quired pole setting depth. Communication space
in compression type lugs or connectors filled with
a high temperature oxide inhibitor compound.
will include allowance for telephone lines, and
may include allowance for fire alarm, television, or
6-4. Poles.
other signal circuits as required. If at the time of
a. Types. Solid wood poles will be used for
design, exact requirements cannot be determined,
electric distribution lines, while concrete and steel
a 2-foot space allocation is ample and will be
poles will be used for roadway or area lighting
provided on all poles even though present plans do
circuits carried underground or separately from
not include telephone lines. Longer poles will be
distribution lines. Concrete or steel poles may be
provided in areas where the future installation of
justified for medium-voltage distribution circuits
additional electric circuits and equipment can be
w h e r e wood poles do not provide adequate
reasonably expected. Pole strengths will meet the
strength, or where climatic conditions cause wood
NESC requirements for grade "B" construction for
poles to deteriorate rapidly. Laminated wood poles
the applicable loading district. Since the normal
will not be used for electric distribution lines.
maintenance activity does not have the financial
However, in some instances the surrounding envi-
or personnel capabilities of a utility, it may be
ronment may make their installation appropriate
necessary to use pole strengths greater than code
for roadway and area lighting applications.
minimums. Table 6-4 indicates pole lengths and
(1) Wood poles. Solid wood poles are covered
classes (strengths) which are considered the mini-
by ANSI 05.1. Pole strengths are designated by
mum for normal use. Poles less than 40 feet in
classes 1 through 10 for normal strengths and H1
length, or classes 6 through 10, will not be
through H6 for higher strengths. These classes
installed for medium-voltage lines. The required
establish pole circumference limitations for each
pole embedment is dependent upon the loading
class and species of wood.
district and upon soil conditions. A pole length and
(2) Concrete poles. Normal reinforced concrete
strength calculation is shown on figure 6-2.
poles are not strong enough for the wind and ice
c. Pole-setting depths. In normal firm ground,
loads which prevail in some areas. Either centrifu-
minimum pole-setting depths will be as shown in
gally spun or cast, prestressed concrete poles are
table 6-5. In rocky or swampy soil, pole-setting
acceptable, but special pole design, based on calcu-
depths will be decreased or increased accordingly.
lations of pole loads, will be necessary to assure
adequate strength. Where strength requirements
Table 6-4. Minimum Primary Wood Pole Lengths and Classes
dictate excessive concrete pole diameters, steel
poles will be used.
Length
(3) Tapered tubular metal poles. Galvanized
Class
feet
steel poles are covered by AASHTO LTS-2, but no
40....................................
4 or 5
classes are given. Aluminum poles are not accept-
45 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3 or 4
able, since corrosion may be a problem and alumi-
2 or 3
50....................................
num poles do not provide adequate strength.
Table 6-5. Minimum Pole-Setting Depth.
(Feet and Inches)
Curves,
Curves,
Pole
Straight
Corners, and
Pole
Straight
Corners, and
Length
Pole
Length
Pole
Points of
Points of
Lines
Lines
Extra Strain
(Feet)
Extra Strain
(feet)
5-0
8-6
20
5-0
65
9-0
70
9-0
25
5-6
5-6
9-6
30
5-6
5-6
75
9-6
10-0
35
6-0
6-0
80
10-0
10-6
40
6-0
6-6
85
10-6
11-0
45
6-6
7-0
90
11-0
11-6
50
7-0
7-6
95
11-6
12-0
55
7-6
8-0
100
12-0
12-6
60
8-0
8-6
6-6
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