1kV及(ji)(ji)以(yi)下的(de)4芯(xin)(xin)電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)（3+1電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)），其中的(de)第(di)4芯(xin)(xin)除(chu)作(zuo)為保(bao)護接(jie)(jie)地外，還要(yao)輸送電(dian)(dian)(dian)(dian)(dian)(dian)力系統在不(bu)(bu)平衡(heng)電(dian)(dian)(dian)(dian)(dian)(dian)流及(ji)(ji)短路(lu)電(dian)(dian)(dian)(dian)(dian)(dian)流。它(ta)的(de)大(da)小由(you)不(bu)(bu)平衡(heng)電(dian)(dian)(dian)(dian)(dian)(dian)流及(ji)(ji)短路(lu)電(dian)(dian)(dian)(dian)(dian)(dian)流來確定，淮(huai)南電(dian)(dian)(dian)(dian)(dian)(dian)線(xian)(xian)，但(dan)一般不(bu)(bu)得(de)小于(yu)相(xiang)線(xian)(xian)的(de)1/2。1kV及(ji)(ji)其以(yi)下三相(xiang)四線(xian)(xian)制(zhi)低壓配電(dian)(dian)(dian)(dian)(dian)(dian)系統，當(dang)保(bao)護線(xian)(xian)和中性線(xian)(xian)合用(yong)同(tong)一導體(ti)時，應采用(yong)4芯(xin)(xin)電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)，而不(bu)(bu)得(de)采用(yong)3芯(xin)(xin)電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)加單芯(xin)(xin)電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)組合成一回路(lu)的(de)方式，甚(shen)至直接(jie)(jie)利用(yong)3芯(xin)(xin)電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)的(de)金屬護套(tao)或(huo)鎧裝層(ceng)等(deng)作(zuo)中性線(xian)(xian)的(de)方式。否則，當(dang)3相(xiang)電(dian)(dian)(dian)(dian)(dian)(dian)流不(bu)(bu)平衡(heng)時，相(xiang)當(dang)于(yu)單芯(xin)(xin)電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)的(de)運行狀態，容易引起工頻干擾。

電(dian)(dian)(dian)(dian)纜(lan)(lan)使用(yong)久(jiu)了或者(zhe)沒有(you)采取相應的(de)(de)維(wei)護(hu)措施(shi)，其表(biao)面(mian)會受到損壞;這時候電(dian)(dian)(dian)(dian)線(xian)電(dian)(dian)(dian)(dian)纜(lan)(lan)維(wei)修(xiu)(xiu)(xiu)人員要對其進(jin)行一定的(de)(de)修(xiu)(xiu)(xiu)復;特別是電(dian)(dian)(dian)(dian)線(xian)電(dian)(dian)(dian)(dian)纜(lan)(lan)在敷設之后(hou)出(chu)(chu)問(wen)題(ti)(ti)之后(hou)的(de)(de)維(wei)修(xiu)(xiu)(xiu)問(wen)題(ti)(ti)稍(shao)微(wei)難(nan)，電(dian)(dian)(dian)(dian)線(xian)電(dian)(dian)(dian)(dian)線(xian)電(dian)(dian)(dian)(dian)纜(lan)(lan).價(jia)錢(qian)，那(nei)么如果西安電(dian)(dian)(dian)(dian)線(xian)電(dian)(dian)(dian)(dian)纜(lan)(lan)出(chu)(chu)現問(wen)題(ti)(ti)了，應該如何修(xiu)(xiu)(xiu)補(bu)呢?通(tong)常情況下，使用(yong)以下辦(ban)法進(jin)行修(xiu)(xiu)(xiu)復：1。擊穿點、孔眼、塌坑等修(xiu)(xiu)(xiu)補(bu)方法用(yong)刀(dao)(dao)修(xiu)(xiu)(xiu)整(zheng)缺陷，高溫電(dian)(dian)(dian)(dian)線(xian)電(dian)(dian)(dian)(dian)纜(lan)(lan)廠，并(bing)剖割(ge)成45°角(jiao)的(de)(de)坡形(xing)狀大小一致的(de)(de)塑料塊，電(dian)(dian)(dian)(dian)線(xian)電(dian)(dian)(dian)(dian)纜(lan)(lan)，放在修(xiu)(xiu)(xiu)補(bu)區上(shang)，用(yong)鉗子(zi)或螺絲刀(dao)(dao)固定好(hao)，然后(hou)用(yong)熱風速(su)焊(han)(han)連續焊(han)(han)好(hao)，用(yong)銅片壓實、壓緊、壓平。

生產電(dian)線電(dian)纜(lan)的(de)主要(yao)原材料(liao)(liao)是電(dian)解銅、絕(jue)(jue)緣(yuan)材料(liao)(liao)和(he)(he)(he)護(hu)套料(liao)(liao)。目(mu)前(qian)原材料(liao)(liao)市場上電(dian)解銅每噸在7萬元以上，而(er)回(hui)收(shou)的(de)雜(za)銅則便宜很多(duo)；絕(jue)(jue)緣(yuan)材料(liao)(liao)和(he)(he)(he)護(hu)套料(liao)(liao)的(de)產品(pin)(pin)和(he)(he)(he)殘次品(pin)(pin)的(de)差價更懸殊。另(ling)外，長(chang)度(du)(du)不足、絕(jue)(jue)緣(yuan)體含膠(jiao)量不夠，也是造成(cheng)價格差異(yi)的(de)重要(yao)原因。每盤線長(chang)度(du)(du)，優等(deng)品(pin)(pin)是100米，而(er)次品(pin)(pin)只(zhi)(zhi)有90米左右；絕(jue)(jue)緣(yuan)體含膠(jiao)量優等(deng)品(pin)(pin)占(zhan)35%～40%，而(er)殘次品(pin)(pin)只(zhi)(zhi)有15%。通過對比，消費(fei)者不難看(kan)出，成(cheng)品(pin)(pin)電(dian)線電(dian)纜(lan)銷售價格存在差異(yi)是材質上存在貓膩所致。