電(dian)纜(lan)按內(nei)導(dao)體(ti)的不同(tong)來分(fen)，主要有兩種(zhong)，一種(zhong)是(shi)純銅(tong)材(cai)料，一種(zhong)是(shi)銅(tong)包(bao)鋁(lv)(lv)(lv)(lv)材(cai)料。銅(tong)包(bao)鋁(lv)(lv)(lv)(lv)的英文是(shi)：Copper Clad Aluminum，所(suo)以銅(tong)包(bao)鋁(lv)(lv)(lv)(lv)導(dao)體(ti)也常稱為：CCA導(dao)體(ti)。銅(tong)包(bao)鋁(lv)(lv)(lv)(lv)復合線材(cai)最早由(you)德(de)國(guo)(guo)(guo)(guo)(guo)在(zai)(zai)上(shang)個(ge)(ge)世紀30年(nian)(nian)代(dai)推(tui)出，隨(sui)后(hou)在(zai)(zai)英國(guo)(guo)(guo)(guo)(guo)、美國(guo)(guo)(guo)(guo)(guo)、法國(guo)(guo)(guo)(guo)(guo)等國(guo)(guo)(guo)(guo)(guo)得以推(tui)廣，廣泛(fan)應用(yong)于各個(ge)(ge)領域。美國(guo)(guo)(guo)(guo)(guo)的CATV電(dian)纜(lan)早在(zai)(zai)1968年(nian)(nian)就開(kai)始試(shi)用(yong)銅(tong)包(bao)鋁(lv)(lv)(lv)(lv)線，消耗數量(liang)達3萬(wan)噸(dun)/年(nian)(nian)。現在(zai)(zai)美洲(zhou)國(guo)(guo)(guo)(guo)(guo)家已經用(yong)銅(tong)包(bao)鋁(lv)(lv)(lv)(lv)(鋼)電(dian)纜(lan)代(dai)替(ti)了純銅(tong)電(dian)纜(lan)。近年(nian)(nian)來，我國(guo)(guo)(guo)(guo)(guo)銅(tong)包(bao)鋁(lv)(lv)(lv)(lv)CATV電(dian)纜(lan)也開(kai)始被大(da)量(liang)使用(yong)。國(guo)(guo)(guo)(guo)(guo)家于2000年(nian)(nian)制定了行(xing)業(ye)標準(zhun)--SJ/T11223-2000，大(da)力推(tui)廣宣傳使用(yong)銅(tong)包(bao)鋁(lv)(lv)(lv)(lv)電(dian)纜(lan)。目(mu)前上(shang)海、廣州、浙(zhe)江、遼寧等地的有線電(dian)視臺已經普遍采用(yong)了銅(tong)包(bao)鋁(lv)(lv)(lv)(lv)電(dian)纜(lan)，反(fan)應良好。

　　銅包鋁(lv)是在(zai)(zai)鋁(lv)或鋁(lv)/鋼合(he)金芯材表(biao)面同心(xin)包覆銅層，經拉拔而(er)成，銅層厚(hou)度(du)在(zai)(zai)0.55mm以(yi)上。由于(yu)高頻(pin)信號在(zai)(zai)導體(ti)(ti)上傳(chuan)輸(shu)(shu)具有趨膚效應的(de)特(te)點，有線(xian)電(dian)視信號在(zai)(zai)0.008mm以(yi)上的(de)銅層表(biao)面傳(chuan)遞，銅包鋁(lv)內導體(ti)(ti)能完全滿(man)足(zu)信號傳(chuan)輸(shu)(shu)要(yao)求，其信號的(de)傳(chuan)輸(shu)(shu)特(te)性(xing)與相同直徑線(xian)銅體(ti)(ti)相一致。

　　可(ke)以將銅(tong)包鋁和純銅(tong)進行以下三方面的比較：

　　機械特性：

　　純(chun)(chun)(chun)銅(tong)(tong)(tong)導(dao)(dao)體(ti)(ti)強度、伸長率比銅(tong)(tong)(tong)包(bao)(bao)(bao)鋁(lv)(lv)導(dao)(dao)體(ti)(ti)大(da)，也就是(shi)說純(chun)(chun)(chun)銅(tong)(tong)(tong)在(zai)(zai)機械性能(neng)方(fang)面比銅(tong)(tong)(tong)包(bao)(bao)(bao)鋁(lv)(lv)好。從電纜(lan)(lan)(lan)設(she)計的角(jiao)度來看，純(chun)(chun)(chun)銅(tong)(tong)(tong)導(dao)(dao)體(ti)(ti)比銅(tong)(tong)(tong)包(bao)(bao)(bao)鋁(lv)(lv)導(dao)(dao)體(ti)(ti)機械強度好的優(you)點(dian)，在(zai)(zai)實際應(ying)用過程中(zhong)不一定需要(yao)。銅(tong)(tong)(tong)包(bao)(bao)(bao)鋁(lv)(lv)導(dao)(dao)體(ti)(ti)比純(chun)(chun)(chun)銅(tong)(tong)(tong)輕(qing)(qing)很多，因此銅(tong)(tong)(tong)包(bao)(bao)(bao)鋁(lv)(lv)的電纜(lan)(lan)(lan)在(zai)(zai)整體(ti)(ti)重(zhong)量上比純(chun)(chun)(chun)銅(tong)(tong)(tong)導(dao)(dao)體(ti)(ti)電纜(lan)(lan)(lan)要(yao)輕(qing)(qing)，這(zhe)樣會給電纜(lan)(lan)(lan)的運輸和電纜(lan)(lan)(lan)的架設(she)施工(gong)帶來方(fang)便(bian)。另(ling)外銅(tong)(tong)(tong)包(bao)(bao)(bao)鋁(lv)(lv)比純(chun)(chun)(chun)銅(tong)(tong)(tong)軟一點(dian)，用銅(tong)(tong)(tong)包(bao)(bao)(bao)鋁(lv)(lv)導(dao)(dao)體(ti)(ti)生產的電纜(lan)(lan)(lan)在(zai)(zai)柔軟性方(fang)面比純(chun)(chun)(chun)銅(tong)(tong)(tong)的電纜(lan)(lan)(lan)好一點(dian)。

　　電氣性能：

　　因(yin)(yin)為鋁的(de)導(dao)(dao)電性比(bi)銅(tong)(tong)(tong)(tong)(tong)差，使得(de)銅(tong)(tong)(tong)(tong)(tong)包鋁導(dao)(dao)體(ti)的(de)直流(liu)電阻比(bi)純(chun)銅(tong)(tong)(tong)(tong)(tong)導(dao)(dao)體(ti)大(da)，這(zhe)點有無(wu)影(ying)響主要2014年中考沖刺綜合復習指導(dao)(dao)北京地區試(shi)題(ti)廣東地區試(shi)題(ti)江蘇地區試(shi)題(ti)看電纜(lan)是(shi)否(fou)會被(bei)用供(gong)電，如給放大(da)器(qi)提供(gong)電源(yuan)，如果(guo)被(bei)用來供(gong)電的(de)話，銅(tong)(tong)(tong)(tong)(tong)包鋁導(dao)(dao)體(ti)將會導(dao)(dao)致(zhi)額外的(de)電力消(xiao)耗(hao)，電壓降(jiang)低較(jiao)多。當頻(pin)率超過5MHz時(shi)，此(ci)時(shi)的(de)交(jiao)流(liu)電阻衰減(jian)(jian)在這(zhe)兩種(zhong)不(bu)同(tong)的(de)導(dao)(dao)體(ti)下(xia)沒有明顯的(de)區別(bie)。當然，這(zhe)主要是(shi)因(yin)(yin)為高頻(pin)電流(liu)的(de)集膚(fu)效(xiao)應，頻(pin)率越高，電流(liu)的(de)流(liu)動就越接近(jin)導(dao)(dao)體(ti)表(biao)(biao)面，在銅(tong)(tong)(tong)(tong)(tong)包鋁導(dao)(dao)體(ti)的(de)表(biao)(biao)面實(shi)際上純(chun)銅(tong)(tong)(tong)(tong)(tong)材(cai)料(liao)，當頻(pin)率高到一定(ding)時(shi)候，整個電流(liu)鍍(du)在銅(tong)(tong)(tong)(tong)(tong)材(cai)質里(li)面流(liu)動了。在5MHz情況下(xia)，電流(liu)在近(jin)表(biao)(biao)面的(de)約0.025毫米厚(hou)度中流(liu)動，而(er)銅(tong)(tong)(tong)(tong)(tong)包鋁導(dao)(dao)體(ti)的(de)銅(tong)(tong)(tong)(tong)(tong)層厚(hou)度比(bi)此(ci)厚(hou)度多約一倍。對于同(tong)軸(zhou)電纜(lan)，因(yin)(yin)為傳輸的(de)信號是(shi)在5MHz以上，因(yin)(yin)此(ci)銅(tong)(tong)(tong)(tong)(tong)包鋁導(dao)(dao)體(ti)和純(chun)銅(tong)(tong)(tong)(tong)(tong)導(dao)(dao)體(ti)傳輸效(xiao)果(guo)是(shi)相同(tong)的(de)。在實(shi)際測試(shi)電纜(lan)的(de)衰減(jian)(jian)可以證明這(zhe)一點。

　　銅包(bao)鋁(lv)較(jiao)純(chun)(chun)銅導體軟(ruan)，在(zai)生產過程中容易進行矯直處理，因(yin)此在(zai)一(yi)定程度上可以說用銅包(bao)鋁(lv)的(de)電纜要比用純(chun)(chun)銅導體的(de)電纜回(hui)波損(sun)耗指標好。

　　經濟性：

　　銅(tong)(tong)(tong)包鋁(lv)導體是(shi)(shi)按(an)重(zhong)(zhong)量出售的(de)(de)，純銅(tong)(tong)(tong)導體也是(shi)(shi)按(an)重(zhong)(zhong)量出售的(de)(de)，銅(tong)(tong)(tong)包鋁(lv)導體的(de)(de)價格要比相(xiang)同(tong)重(zhong)(zhong)量的(de)(de)純銅(tong)(tong)(tong)導體貴一(yi)些(xie)。但是(shi)(shi)同(tong)樣重(zhong)(zhong)量的(de)(de)銅(tong)(tong)(tong)包鋁(lv)要比純銅(tong)(tong)(tong)導體長度(du)長很多，而(er)電(dian)(dian)纜(lan)是(shi)(shi)按(an)長度(du)計算的(de)(de)。相(xiang)同(tong)重(zhong)(zhong)量銅(tong)(tong)(tong)包鋁(lv)線(xian)是(shi)(shi)銅(tong)(tong)(tong)線(xian)長度(du)的(de)(de)2.5倍，價格僅僅是(shi)(shi)每噸多幾百元。綜合下來(lai)，銅(tong)(tong)(tong)包鋁(lv)就很有優勢。由于銅(tong)(tong)(tong)包鋁(lv)電(dian)(dian)纜(lan)比較(jiao)輕，電(dian)(dian)纜(lan)的(de)(de)運(yun)輸(shu)成本、安裝(zhuang)架設成本都會(hui)有所降低，會(hui)給(gei)施工帶來(lai)一(yi)定(ding)的(de)(de)方便性。

　　易維護性：

　　使用(yong)(yong)銅(tong)包鋁(lv)(lv)能減(jian)少(shao)網絡(luo)故(gu)障，避免網絡(luo)人員在(zai)維護時"冬天(tian)(tian)剪(jian)芯，夏天(tian)(tian)剪(jian)皮"（鋁(lv)(lv)帶縱包或鋁(lv)(lv)管產品）。由于電纜(lan)的銅(tong)內導(dao)體(ti)(ti)與鋁(lv)(lv)外(wai)導(dao)體(ti)(ti)熱膨脹系數相(xiang)差較(jiao)(jiao)大，在(zai)炎熱的夏季，鋁(lv)(lv)外(wai)導(dao)體(ti)(ti)伸張(zhang)較(jiao)(jiao)大，銅(tong)內導(dao)體(ti)(ti)相(xiang)對回縮(suo)，不能充分接觸到F頭座內的彈性觸片；在(zai)嚴(yan)寒的冬季，鋁(lv)(lv)外(wai)導(dao)體(ti)(ti)收(shou)縮(suo)較(jiao)(jiao)大，使屏蔽層脫落(luo)。當同軸電纜(lan)采(cai)用(yong)(yong)銅(tong)包鋁(lv)(lv)內導(dao)體(ti)(ti)時，它與鋁(lv)(lv)外(wai)導(dao)體(ti)(ti)的熱膨脹系數相(xiang)差較(jiao)(jiao)小，氣溫變化時，電纜(lan)抽(chou)芯的故(gu)障大為(wei)減(jian)少(shao)，提(ti)高了網絡(luo)的傳輸(shu)質量。

　　總的(de)來講，銅包鋁(lv)導(dao)體(ti)總體(ti)性能要比(bi)純銅導(dao)體(ti)好(hao)，它將節約用戶(hu)的(de)費用。

　　業(ye)內人士認為，電線(xian)(xian)(xian)電纜行業(ye)采用銅(tong)包鋁(lv)(lv)線(xian)(xian)(xian)也是一種緩解目前企業(ye)壓(ya)力(li)的好辦法。鋁(lv)(lv)線(xian)(xian)(xian)外面(mian)包一層銅(tong)經拉制而(er)(er)成(cheng)的雙金(jin)屬線(xian)(xian)(xian)，由(you)于具(ju)有比(bi)重小(xiao)，傳輸性能好等優(you)點，特(te)別適用于做(zuo)射頻同軸(zhou)(zhou)電纜的內導體，與純銅(tong)線(xian)(xian)(xian)相比(bi)，其密度(du)為純銅(tong)40%左右。而(er)(er)傳輸特(te)性優(you)于純銅(tong)線(xian)(xian)(xian)，是最理想的射頻同軸(zhou)(zhou)電纜分支線(xian)(xian)(xian)內導體。