ABSTRACT
OH construction* is only 15%–60% as costly as underground and is therefore more economical. The Šrst consideration in the design of an OH line, of course, is its electrical characteristics. As explained in the previous chapters, the electrical design of the line must be sufŠcient for the required power to be transmitted without excessive voltage drop and/or energy losses, and the line insulation must be adequate to cope with the system voltage. The mechanical factors inªuencing the design must then be considered. For example, the poles supporting the conductors must have sufŠcient mechanical strength to withstand all expected loads. Another example is that the material chosen for the conductors must be strong enough to withstand the forces to which it is subjected.
