電線電纜因導(dao)線(xian)過(guo)載而起(qi)火該(gai)如何預(yu)防

   電(dian)線(xian)(xian)(xian)(xian)(xian)(xian)電(dian)纜(lan)在(zai)(zai)(zai)(zai)(zai)運(yun)行(xing)的(de)(de)過(guo)程中(zhong)，由于(yu)電(dian)阻的(de)(de)存在(zai)(zai)(zai)(zai)(zai)會(hui)發熱(re)(re)(re)。導(dao)(dao)(dao)(dao)線(xian)(xian)(xian)(xian)(xian)(xian)的(de)(de)電(dian)阻一般(ban)都很小，其發熱(re)(re)(re)功(gong)率(lv)可以(yi)用(yong)公式q=I^2R表示。q=I^2R表明(ming)：對(dui)于(yu)一段(duan)實際使用(yong)中(zhong)的(de)(de)導(dao)(dao)(dao)(dao)線(xian)(xian)(xian)(xian)(xian)(xian)來說(R已基(ji)本恒定)，通過(guo)導(dao)(dao)(dao)(dao)線(xian)(xian)(xian)(xian)(xian)(xian)的(de)(de)電(dian)流越大(da)(da)，其發熱(re)(re)(re)功(gong)率(lv)也(ye)(ye)越大(da)(da);若電(dian)流量(liang)恒定，則導(dao)(dao)(dao)(dao)線(xian)(xian)(xian)(xian)(xian)(xian)的(de)(de)發熱(re)(re)(re)功(gong)率(lv)也(ye)(ye)是(shi)恒定的(de)(de)。在(zai)(zai)(zai)(zai)(zai)運(yun)行(xing)過(guo)程中(zhong)放(fang)(fang)(fang)出(chu)(chu)的(de)(de)熱(re)(re)(re)量(liang)會(hui)被(bei)導(dao)(dao)(dao)(dao)線(xian)(xian)(xian)(xian)(xian)(xian)自(zi)身吸(xi)收從(cong)而引起導(dao)(dao)(dao)(dao)線(xian)(xian)(xian)(xian)(xian)(xian)溫(wen)度(du)(du)的(de)(de)升高。導(dao)(dao)(dao)(dao)線(xian)(xian)(xian)(xian)(xian)(xian)在(zai)(zai)(zai)(zai)(zai)運(yun)行(xing)過(guo)程中(zhong)雖然不(bu)停地在(zai)(zai)(zai)(zai)(zai)吸(xi)收電(dian)流做(zuo)功(gong)釋放(fang)(fang)(fang)的(de)(de)熱(re)(re)(re)量(liang)，但(dan)其溫(wen)度(du)(du)不(bu)會(hui)無限(xian)制的(de)(de)上(shang)升。因為導(dao)(dao)(dao)(dao)線(xian)(xian)(xian)(xian)(xian)(xian)在(zai)(zai)(zai)(zai)(zai)吸(xi)熱(re)(re)(re)的(de)(de)同時，也(ye)(ye)在(zai)(zai)(zai)(zai)(zai)不(bu)斷(duan)地向(xiang)外界放(fang)(fang)(fang)熱(re)(re)(re)，事實表明(ming)，導(dao)(dao)(dao)(dao)線(xian)(xian)(xian)(xian)(xian)(xian)通電(dian)后溫(wen)度(du)(du)逐漸上(shang)升，最(zui)后溫(wen)度(du)(du)恒定在(zai)(zai)(zai)(zai)(zai)某個點上(shang)。在(zai)(zai)(zai)(zai)(zai)這(zhe)(zhe)個恒定點上(shang)，導(dao)(dao)(dao)(dao)線(xian)(xian)(xian)(xian)(xian)(xian)吸(xi)、放(fang)(fang)(fang)熱(re)(re)(re)功(gong)率(lv)一致(zhi)，導(dao)(dao)(dao)(dao)線(xian)(xian)(xian)(xian)(xian)(xian)處于(yu)熱(re)(re)(re)平衡(heng)狀態。導(dao)(dao)(dao)(dao)線(xian)(xian)(xian)(xian)(xian)(xian)承受較高溫(wen)度(du)(du)運(yun)行(xing)的(de)(de)能力是(shi)有(you)限(xian)度(du)(du)的(de)(de)，超過(guo)某個最(zui)高溫(wen)度(du)(du)運(yun)行(xing)會(hui)出(chu)(chu)現危(wei)險。這(zhe)(zhe)個最(zui)高溫(wen)度(du)(du)自(zi)然也(ye)(ye)對(dui)應某個最(zui)大(da)(da)電(dian)流，導(dao)(dao)(dao)(dao)線(xian)(xian)(xian)(xian)(xian)(xian)超過(guo)這(zhe)(zhe)個最(zui)大(da)(da)電(dian)流運(yun)行(xing)即是(shi)過(guo)載。導(dao)(dao)(dao)(dao)線(xian)(xian)(xian)(xian)(xian)(xian)過(guo)載直接導(dao)(dao)(dao)(dao)致(zhi)導(dao)(dao)(dao)(dao)線(xian)(xian)(xian)(xian)(xian)(xian)本身及其附近物品溫(wen)度(du)(du)升高。溫(wen)度(du)(du)升高是(shi)導(dao)(dao)(dao)(dao)致(zhi)該類火(huo)災最(zui)為直接的(de)(de)原(yuan)因。

   過載(zai)使(shi)雙(shuang)股導線(xian)(xian)間(jian)絕(jue)緣(yuan)(yuan)層(ceng)破壞引(yin)(yin)起短路，燒毀設備(bei)，引(yin)(yin)發火災。雙(shuang)股導線(xian)(xian)靠其(qi)間(jian)絕(jue)緣(yuan)(yuan)層(ceng)隔(ge)開，過載(zai)使(shi)絕(jue)緣(yuan)(yuan)層(ceng)軟化破壞，從(cong)而導致(zhi)兩股導線(xian)(xian)直(zhi)接接觸引(yin)(yin)起短路，燒損設備(bei)。同時短路瞬間(jian)大電流產生(sheng)的(de)高溫(wen)(wen)使(shi)線(xian)(xian)路起火、熔斷，產生(sheng)的(de)熔珠(zhu)落至可燃(ran)物(wu)引(yin)(yin)發火災。過載(zai)溫(wen)(wen)升還能直(zhi)接引(yin)(yin)燃(ran)附(fu)近(jin)(jin)可燃(ran)物(wu)。過載(zai)導線(xian)(xian)傳(chuan)熱(re)使(shi)附(fu)近(jin)(jin)可燃(ran)物(wu)溫(wen)(wen)度升高，對附(fu)近(jin)(jin)燃(ran)點較低的(de)可燃(ran)物(wu)來講，將其(qi)引(yin)(yin)燃(ran)造成火災是(shi)有可能的(de)。在貯(zhu)存(cun)易(yi)燃(ran)物(wu)品的(de)庫房和使(shi)用易(yi)、可燃(ran)裝(zhuang)修(xiu)的(de)建筑(zhu)中，這種危險性尤為突出(chu)。

過載還(huan)使線路中的(de)(de)連接(jie)處在過熱的(de)(de)條件下，這加(jia)速了其氧(yang)化的(de)(de)過程。氧(yang)化使連接(jie)點處產生不易導電的(de)(de)薄薄一層(ceng)氧(yang)化膜，氧(yang)化膜加(jia)大(da)了接(jie)觸點間(jian)的(de)(de)電阻，從而(er)產生打火等現象，引起火災。

那么(me)，如(ru)何預(yu)防因電(dian)線(xian)電(dian)纜(lan)過載而起火呢?

1、在線(xian)(xian)路設(she)(she)(she)計(ji)過(guo)(guo)程中，應該準確核(he)定(ding)該場所容(rong)量，充分考慮以(yi)后新(xin)(xin)增容(rong)量的(de)(de)(de)可能性，選(xuan)擇合(he)適型(xing)(xing)號(hao)的(de)(de)(de)導線(xian)(xian)。容(rong)量大，應選(xuan)擇較粗的(de)(de)(de)導線(xian)(xian)。線(xian)(xian)路設(she)(she)(she)計(ji)，合(he)理(li)選(xuan)型(xing)(xing)是預防過(guo)(guo)載的(de)(de)(de)關鍵(jian)步驟。如果設(she)(she)(she)計(ji)選(xuan)型(xing)(xing)不(bu)當，會(hui)留下難(nan)以(yi)整改(gai)的(de)(de)(de)先天(tian)性隱患。某些(xie)小型(xing)(xing)工(gong)程、場所不(bu)認(ren)真設(she)(she)(she)計(ji)選(xuan)型(xing)(xing)。隨意選(xuan)擇、敷設(she)(she)(she)線(xian)(xian)路，這(zhe)是非常危險的(de)(de)(de)。新(xin)(xin)增電(dian)器、用電(dian)設(she)(she)(she)備應該充分考慮原(yuan)有(you)線(xian)(xian)路的(de)(de)(de)承受能力。原(yuan)來線(xian)(xian)路不(bu)符合(he)要(yao)求(qiu)的(de)(de)(de)，應該重(zhong)新(xin)(xin)設(she)(she)(she)計(ji)、改(gai)造。

2、線(xian)(xian)路(lu)(lu)應(ying)該(gai)按(an)照有關規范要求，讓(rang)有電(dian)工資(zi)格人(ren)員施工敷(fu)設(she)。線(xian)(xian)路(lu)(lu)的敷(fu)設(she)條件直(zhi)接影響導線(xian)(xian)的散(san)熱情況(kuang)。一般(ban)來(lai)講(jiang)，線(xian)(xian)路(lu)(lu)敷(fu)設(she)不應(ying)該(gai)穿(chuan)(chuan)越易(yi)、可燃物(wu)質、堆(dui)垛，這樣(yang)會(hui)導致導線(xian)(xian)散(san)熱不暢，熱量(liang)蓄積，產(chan)生引燃周圍(wei)可燃物(wu)品的可能性(xing)，加大了過載情況(kuang)下引起(qi)火(huo)災的危(wei)險(xian)性(xing);公(gong)共娛(yu)樂場所裝修吊頂內敷(fu)設(she)線(xian)(xian)路(lu)(lu)應(ying)穿(chuan)(chuan)鋼管保護，以(yi)使(shi)吊頂與線(xian)(xian)路(lu)(lu)隔開，在過載、短(duan)路(lu)(lu)等(deng)情況(kuang)即使(shi)有熔(rong)珠(zhu)也(ye)不會(hui)掉落，避(bi)免(mian)火(huo)災發生。

3、加強用(yong)電(dian)管理，避免亂接(jie)線(xian)(xian)(xian)、亂搭線(xian)(xian)(xian)，謹慎(shen)使(shi)用(yong)移(yi)動(dong)(dong)(dong)插(cha)座。亂接(jie)線(xian)(xian)(xian)、亂搭線(xian)(xian)(xian)、使(shi)用(yong)移(yi)動(dong)(dong)(dong)插(cha)座其(qi)實就(jiu)是在某段(duan)線(xian)(xian)(xian)路上(shang)(shang)(shang)添加了用(yong)電(dian)設備，加大(da)了電(dian)流量從而有可能引(yin)起過載。移(yi)動(dong)(dong)(dong)插(cha)座插(cha)孔明(ming)顯多于墻上(shang)(shang)(shang)的(de)固定插(cha)座，若移(yi)動(dong)(dong)(dong)插(cha)座上(shang)(shang)(shang)使(shi)用(yong)過多電(dian)器設備，原有線(xian)(xian)(xian)路必定難以承受(shou)。對于較(jiao)大(da)功率的(de)設備、電(dian)器宜(yi)設單(dan)獨的(de)線(xian)(xian)(xian)路，不宜(yi)使(shi)用(yong)移(yi)動(dong)(dong)(dong)插(cha)座作為(wei)接(jie)線(xian)(xian)(xian)源。

4、加快老(lao)線路(lu)(lu)的(de)更新(xin)改造，消除火災(zai)隱患。老(lao)企業、老(lao)居民區等單(dan)位，由于使(shi)用(yong)(yong)時間較(jiao)為久遠，許多線路(lu)(lu)已(yi)經老(lao)化(hua)，超過(guo)了使(shi)用(yong)(yong)年限。部分線路(lu)(lu)的(de)載流(liu)量即使(shi)不(bu)大，但(dan)老(lao)化(hua)線路(lu)(lu)也難(nan)以承受(shou)這樣的(de)載流(liu)量，也具有過(guo)載所表現出(chu)來的(de)危(wei)險性。特別是老(lao)居民區，線路(lu)(lu)早已(yi)老(lao)化(hua)，但(dan)隨著人(ren)們生活水(shui)平提高，家(jia)用(yong)(yong)電(dian)器的(de)增加，其(qi)用(yong)(yong)電(dian)量仍(reng)在逐年上升，真是雪上加霜。對于老(lao)舊線路(lu)(lu)，應(ying)該(gai)及時督促、協調，盡快促其(qi)整改，以消除火災(zai)隱患，保證安全。