Page 22 of 23 Guide for Installation and use of Southwire C
7
Overhead Conductor
Many dampers utilize armor rods to provide added protection for C
7
. Dampers with rubber-
lined clamps are also acceptable. Check with your damper manufacturer for their
recommendations on use of armor rods with dampers.
Damper Spacing: always locate Stockbridge dampers per the manufacturer’s recommendation.
Placement of spacer/dampers in the span is not critical, and, for example, a damper may be
relocated several meters to avoid a splice, marker sphere, or other obstruction. It is important
to avoid symmetric spacing, as the dampers can cause unwanted movements in the span.
C
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Conductor Repair
If the conductor damage includes evidence of over-bending, kinking, or crushing, the suspect
section should be cut out and a full-tension splice installed. If available, a portable x-ray unit
can confirm the integrity of the core. If the core is confirmed to be intact, or if the damage is
limited to outer abrasion or outer broken aluminum strands, conductor repair kits are available
from both PLP and AFL. The PLP system is similar to their wrap-rod splice, and provides a 100%
repair as long as the core is intact. PLP’s conductor repair manual can be found at:
http://www.preformed.com/images/pdfs/Energy/Transmission/EN-TM-1000-
5_TransmissionManual.pdf
C
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Conductor Maintenance and Operation
C
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conductor should be maintained and operated in a prudent manner to ensure the full service
life is preserved. Company practices for line inspection and maintenance vary according to the
service environment. Some items to consider for any overhead conductor:
• Regular fly-by or drive-by patrols to look for lightning damage, broken strands, broken
or drooping vibration dampers, ROW encroachments and other issues that need follow-
up repair or attention. Monthly is a common interval for cursory inspections.
• Review of system operation and system protection to avoid long-term overloads. C
7
polymer composite core uses materials selected for best tolerance of high temperature,
but should not operate above 180 °C continuously or above 200 °C for longer than 2000
hours during the life of the line. Conductor temperature should never exceed 225 °C.
• Climbing inspections are sometimes needed to check the condition of the hardware and
other small parts that are subject to wear. Drone technology and high-resolution
imagery are becoming competitive with climbing inspection for detecting issues that are
not visible during fly-by or drive-by inspections.
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