Southwire C7 - Conductor Staining

Page 20 of 23 Guide for Installation and use of Southwire C
7
Overhead Conductor
Figure 24: Oxidation on a conductor.
Conductor Staining
When conductor reels are stored outdoors, water can accumulate on the conductor on the
underside of the reel. If the water contains chemicals from the surrounding atmosphere, a
black stain known as a “water stain” can appear on the conductor. This has been found to be
more prevalent in non-specular conductor because the drawing oils have been removed.
Figure 25 shows an example of water staining.
Figure 25: Water stain on conductor.
Water stains are a cosmetic issue; they have no adverse effect on the performance or service
life of the conductor. No corrosion in excess of normal oxidation results from the water stain.
In most environments, the conductor will darken in the first few months after the line is
energized, and the stain will no longer be noticeable. Aluminum Association Technical Bulletin
TR3, “Guidelines for Minimizing Water Staining of Aluminum” discusses this issue in detail and
contains advice for avoiding water staining.