They chose Southwire s oval cross-section conductors for the long span and also a shorter span on either side of it. That particular area is probably as good a test as we could find in our whole company. The spiraling oval cross section gives galloping and vibration resistance equal to or better than twisted pair, without the installation-cost premium. It s available for transmission applications, and we re working on smaller sizes for distribution jobs. Installation cost was a big factor for MidAmerican.
Twisted pair takes extra time and labor in stringing and tensioning.
Where twisted pair takes two splices or terminations per joint, oval conductors use only one. That saves money on both labor and materials. Delivery was speedy. MidAmerican received its oval conductor in under eight weeks, when typical twisted-pair deliveries were being scheduled 25 weeks out. At first, the crew was skeptical.