TM
5-811-1/AFJMAN
32-1080
guy wires. This isolates the anchor from the
additional insulators may be required.
copper grounding systems installed at the poles.
(b) Strain insulator ratings. Ratings and
Furthermore, sacrificial magnesium anodes at-
strengths of insulators will be suitable for the
tached to the anchors may be cost effective.
circuit insulated. Since the maximum available
(c) Grounding conductors and guy wires.
ANSI guy strain insulator strength is 20,000
Grounding conductors will always be copper re-
(20M) pounds this requirement could limit non-
gardless of the type of electrodes used. Guy wires
grounded guy strengths to 20M and may require
will be of the same composition as electrodes and
two or more downguys if more than a 20,000
will be bonded to the hardware grounding conduc-
pound pull is necessary. Stronger insulators, which
tor with approved clamps.
are not ANSI listed, may be used also.
(3) Nongrounded guys. Where guy strain insu-
(4) Anchors. The type of anchor used must
lators are installed in a guy, to provide sectionaliz-
provide suitable resistance to uplift and therefore
ing of grounded portions from nongrounded por-
is dependent upon soil conditions. Table 6-7 indi-
tions, that guy is considered ungrounded. Strain
cates suitable anchor types based on a range of
insulators will be provided in all guys on wood-
soils from hard to soft. While the soil descriptions
poles, except where grounded guys are required or
are not an industry standard, manufacturers are
where local code requires sectionalizing in higher
familiar with this or similar classifications. For
voltage lines.
the majority of cases, the most suitable anchor is
(a) Strain insulator location. Insulators will
an expanding type as shown on figure 6-7, be-
be located in accordance with the NESC and so
cause most lines are installed in ordinary soils.
that in the event a guy wire is broken, the
Strengths for available sizes of expanding anchors
uninsulated upper portion of the guy wire cannot
are also shown on figure 6-7. Rock or swamp
swing to any point less than eight feet above the
anchors are described in manufacturer's catalogs.
ground. Insulators will be located at least six feet
In the past, log anchors consisting of 8-inch to
horizontally from the pole, which will provide
12-inch diameter by 4-foot to 5-foot long creoso-
separation between a lineman and the grounded
ted logs, have been used in marshy soil. Since log
guy wire segment. Where guy wires pass through
anchors tend to rot, no matter how well creosoted
line conductors or can fall on line conductors,
or otherwise treated, their use is prohibited. Ex-
Table 6-7. Anchors Suitable for Various Soils.
6-14
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