Pre twisted wires yog siv los ua kev sib txuas fittings rau cov khoom siv hluav taws xob siv hluav taws xob, nrog rau cov hluav taws xob hluav taws xob hluav taws xob hluav taws xob hluav taws xob, kev ncua, cov pob qij txha, thiab lwm yam. Pre twisted wire thawj zaug hauv Tebchaws Meskas hauv xyoo 1940 thiab 1950s. Nws cov khoom thawj zaug yog cov khoom siv tiv thaiv kab mob uas siv los tiv thaiv kev ntxhov siab hauv cheeb tsam ntawm cov xov hlau liab qab, nrog rau cov chaw cuam tshuam los ntawm hluav taws xob corrosion thiab arc puas. Tom qab xyoo ntawm txoj kev loj hlob, pre twisted hlau fittings tau dav siv nyob rau hauv teb xws li lub hwj chim kis tau tus mob thiab tis, fiber optic kev sib txuas lus, electrified railways, cable TV, kev tsim kho, thiab kev ua liaj ua teb.
Steel cored txhuas hlau yog ib tug mainstream xaim dav siv nyob rau hauv 10 kV tis network kab. Nws muaj cov txiaj ntsig zoo xws li lub zog tensile siab, kev tiv thaiv hluav taws xob zoo, thiab tus nqi qis, thiab siv dav hauv cov pob qij txha hauv nroog thiab cov kab hluav taws xob nyob deb nroog. Txawm li cas los xij, ib zaug steel tub ntxhais aluminium hlau kab puas tsuaj los ntawm sab nraud quab yuam los yog cuam tshuam los ntawm huab cua hnyav, nws yog qhov ua rau cov hlau sib tov thiab luv Circuit Court txhaum. Tom qab ib qho kev sib xyaw luv luv tshwm sim, cov hlau yuav ntsib qhov tshwm sim tawg. Yog tias qhov xwm txheej no raug pom, kev kho cov hlau tsim nyog yuav tsum tau muab rau lub sijhawm kom tsis txhob muaj kev tawg ntawm cov hlua txuas ntxiv, uas tuaj yeem ua rau txo qis hauv cov khoom siv hluav taws xob thiab cov khoom siv hluav taws xob ntawm cov hlau.