Engineering Handbook Copper and Aluminum Cables



This booklet  is designed  to help engineers  in the selection of conductor sizes and help in the installation of cable systems. Information from many sources has been compiled in this booklet for your convenience. The information in Section 1provides general conductor data. Tables are provided which give the cross sectional area, number of strands, outside di­ ameter and weight of solid wire, class Band C strandings and Class G, H and Iflexible strandings.There is also data available to calculate the ac or de resistance of conductors  at many temperatures  and frequencies. Section 2 contains the necessary tables and formulas to determine there­
quired current for a cable circuit.

Normally, the ampacity of a cable is limited by heating but, for some cir­ cuits the voltage drop is important. For this reason, in Section 3 information on voltage regulation is included.Formulas for calculating the voltage drop are given along with a nomogram for determining the reactance of conduc­ tors. For some applications large short circuit currents must be carried. Section
4 contains short circuit ampacities for conductors and shields that may be useful in some applications. The purpose of shielding and the effects of grounding shields are dis­ cussed in Section 5. Tables give the voltages above which shielding should be considered. Formulas for calculating shield losses associated with multi­ grounded shields are presented. Ampacity tables and various correction factors are given in Section 6. The ampacity  data applies  to thermosetting  (vulcanized)  insulations  rated at gooc and 105°C conductor temperatures. The conditions used in calculat­ing table values are given at the top of each table.The appropriate correction
factor for any installation condition varying from those for which the tables were calculated  should be used. Also included is the NFPA 70, National Electrical Code, 600 Volt ampacity table. Cable failures may result from poor installation practices.Compliance with the procedures outlined in Section 7 may prolong the life of a cable.Informa­ tion  on  conduit, buried,  borehole and  self-supporting installations is provided. Information on high voltage de proof testing,reelcapacities, jacket materi­als selection and other miscellaneous information is given in Sections 8 and 9.


The Okonite Company, 2010

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