Insulated cables have many applications in the field of eldctric power。Small cables are used as extension cerds around offices，homes，and faxtories.Larger cables are used for connation to machjnes that are movable over restrictes distances.Insome instances portable cabes carryquite heavy electrical loads,as for example the vase of elevrivally driven drag lines,which require several thousand horsepower for operaion.overhead cables find application in distribuion circuits here tree conditionsor proximitu to buildings and other structures make the use of pen-wire lines impracicable.Underground cables are used in many siuayions,including major transmission ciracitd between large stations,some cable power circuits operate at765kilvots and carry loads of several hundered megawatts,cables of even higher voltage will probably become available soon.
