When is it possible that the weight difference between a squirrel and a fox equals 309 kg/km? Or that the total area of an owl equals 153 mm2 and that of a penguin equals 125 mm2?
To help avoid confusion between different types of aluminium conductor steel-reinforced (ACSR) cables, code words based on animals and birds are used to identify the different types of ACSR conductors.
ACSRs are high-capacity, high-strength conductors general used in overhead power lines. They are comprised of one or more outer layers made of aluminium strands which surround a galvanized steel strand core. The core can be made of a single wire or several steel strands while the outer layer consists of a larger quantity of aluminium strands.
The proportion of steel and aluminium in an ACSR conductor will depend on the mechanical strength and current carrying capacity required for a given application. In order to help differentiate between the various combinations in a simple manner – and avoid referring to a conductor with 72 aluminium strands and 7 steel strands as 72/7 – code words have been adopted.
In North America, bird names have been used while mammal names are used elsewhere. The code names depend on such factors as the weight, diameter, rated strength and current carrying capacity of the ACSR conductor. A conductor data sheet is available that includes data sets for both the mammal and bird code names.
But ACSR conductors are not the only conductors that apply code names. For example, all aluminium conductors (AAC) are given code names from plants while covered aluminium conductors use fruit names in North America.
A full list of the different code names given to overhead aluminium electrical conductors can be found in a white paper prepared by The Aluminum Association in the United States.
The International Standard IEC 61089, developed by TC 7, specifies the electrical and mechanical characteristics of round wire concentric lay overhead electrical stranded conductors. However, it makes no references to plants or animals!