Bare Overhead Conductors
STANDARDS
National :  ASTM B 231
DESCRIPTION
Bare all aluminum conductors (AAC) are concentric-lay-stranded consisting of one or more layers of aluminum alloy 1350 wires wrapped helically around a central wire.  Each successive layer has six wires more than the underlying one.  Increasing the number of wires for any given cross-sectional area provides greater flexibility.  The most commonly used strandings consist of 7, 19, 37, 61 and 91 wires.

Class AA strandings are used for bare overhead lines.  The direction of lay for the outer layer is right-hand and is usually reversed in successive layers.  The temper of the wires is full hard-drawn (H19).

 

Features and Benefits
AAC conductors are the most economical since their lighter weight means lower unit length costs, easier handling during installation and the use of simpler fittings.  They are inherently corrosion resistant due to their homogeneous construction.

Applications
Stranded bare AAC conductors may be used in overhead line installations where the design parameters do not require the higher tensile strength or temperature ratings provided by ACSR, ACCR or other types of conductors.