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Vantage to Pomona Heights Chapter 2 230 kV Transmission Line Project FEIS Proposed Action and Alternatives PAGE 2-27 2.2.3.6 Conductor and Shield Wire Installation Conductors and shield wires would be placed on the transmission line structures by a process called stringing. The first step to wire stringing is the installation of insulators (if not already installed on the structures during ground assembly) and stringing sheaves. Stringing sheaves are rollers that are temporarily attached to the lower portion of the insulators at each transmission line structure to allow conductors to be pulled along the line. Figure 2-6 illustrates the sequence of steps in installing conductors. Additionally, bucket trucks would be used where required prior to stringing any transmission lines over highways, roads, power lines, structures, and other obstacles to prevent ground wire, conductors, or equipment contact during stringing activities. Bucket trucks are trucks fitted with a hinged arm ending in an enclosed platform called a bucket, which can be raised to let the worker in the bucket service portions of the transmission structure as well as the insulators and conductors without climbing the structure. Other safety measures such as barriers, flagmen, or other traffic control would be used. Once the stringing sheaves and temporary clearance structures are in place, the initial stringing operation commences with the pulling of a lighter weight sock line through the sheaves along the same path the transmission line would follow. The sock line can be pulled in via helicopter or by ground-based equipment. The sock line is attached to the hard line, which follows the sock line as it is pulled through the sheaves. The hard line is then attached to the conductor, shield wire or fiber optic ground wire (OPGW) to pull them through the sheaves into their final location. Pulling the lines is accomplished by attaching them to a specialized wire stringing vehicle. Following the initial stringing operation, pulling and tensioning the line would be required to achieve the correct sagging or tension of the transmission lines between support structures. Pulling and tensioning sites for the proposed 230 kV transmission line construction would be required approximately every two miles along the ROW corridor and would encompass approximately 1.1 acres each to accommodate required equipment. Equipment at sites required for pulling and tensioning activities would include tractors and trailers with spooled reels that hold the conductors and trucks with the tensioning equipment. To the extent practicable, pulling and tensioning sites would be located within the ROW corridor. Depending on topography, minor grading may be required at some sites to create level pads for equipment. Finally, the tension and sag of conductors and wires would be fine-tuned, stringing sheaves would be removed, and the conductors would be permanently attached to the insulators at the transmission structures. At the tangent and small angle structures, the conductors would be attached to the insulators using clamps to “suspend” the conductors from the bottom of the insulators. At the larger angle dead-end structures, the conductors cannot be pulled through and so are cut and attached to the insulator assemblies at the structure, thus “dead-ending” the conductors. 2.2.3.7 Helicopter Use Access is required to each transmission structure site for construction and for operation and ongoing maintenance activities. Helicopters may be used to support these activities. Proposed Project construction activities potentially facilitated by helicopters may include delivery of construction laborers, equipment, and materials to structure sites; structure placement; hardware installation; and wire stringing operations. Helicopters may also be used to support the administration and management of the proposed Project. Except in areas of extreme terrain which limits the construction of access roads, the use of helicopter construction methods would not change the need for an access road system required for operating and maintaining the proposed Project because vehicle access is required to each structure site regardless of the construction method employed.