MIL-HDBK-1004/2A
2.1.3
Wire Size. Select wire size in accordance with the current-carrying
capacity required and, where applicable, the voltage-drop limitation.
2.1.4
Physical Features. Select physical design features in accordance
with the type of circuit involved and the type of distribution; that is,
primary or secondary. Select from the following types:
a)
Open wire (bare or weatherproof) on insulators.
b) Aerial cable, self-supported or messenger-supported, consisting
of insulated bundled single-conductor cable or multiple-conductor cable.
2.2
Line Materials. Design pole lines based on materials and
construction methods specified in NFGS-16302.
2.2.1
Poles. Wood, concrete (reinforced with prestressing or
pretensioning), or metal (steel or aluminum) may be used. Use concrete or
metal poles only where they are more economical or special considerations
warrant their use. Treat wood poles and crossarms as covered in NFGS-16302.
2.2.1.2 Heights and Classes. Limitations on pole heights and classes for
wood poles are given in Table 2. Class normally used refers to primary poles
spaced not more than 200 feet (61 m) apart, which serve industrial or housing
areas and which are generally at least 40 feet (12 m) or more in height. See
ANSI C2 for definition of classes. Refer to Table 3 for data on transformer
poles. Refer to Fink and Beaty, Standard Handbook for Electrical Engineers to
determine the limitations on minimum heights and classes for poles carrying
other equipment.
2.2.1.3 Strength Requirements. Refer to Fink and Beaty, Standard Handbook
for Electrical Engineers and ANSI C2 to determine the adequate physical and
structural requirements.
2.2.1.4 Safety Factors.
Refer to ANSI C2 for the minimum safety factors to
be used.
2.2.1.5 Pole Installation. For pole depth, refer to the criteria in Fink
and Beaty, Standard Handbook for Electrical Engineers and ANSI C2. Refer to
Fink and Beaty, Standard Handbook for Electrical Engineers for pole placement
with respect to anchors or braces. Footings or reinforcements of the pole
butt-end shall be as required by foundation conditions.
2.2.1.6 Configuration. Use armless construction for aerial lines because it
is less costly than crossarm construction and its use is aesthetically
preferred. For the same reason, use neutral-supported, secondary cable over
rack-supported individual conductors.
2.2.1.7 Crossarms. Use crossarms mainly for equipment support. Follow the
criteria in Fink and Beaty, Standard Handbook for Electrical Engineers.
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