最近我公司常有(you)客(ke)戶來電(dian)咨(zi)詢(xun)、反映，他們買的BVVB平(ping)行(xing)護(hu)套線(xian)在安(an)裝時，用電(dian)筆(bi)測試線(xian)有(you)時會發亮（顯示有(you)電(dian)），這是(shi)什么原因？個別客(ke)戶甚至懷疑這是(shi)電(dian)線(xian)質量問題。

大(da)家知道，一般家庭用電(dian)進戶線(xian)(xian)(xian)(xian)有三根線(xian)(xian)(xian)(xian)：相線(xian)(xian)(xian)(xian)（火線(xian)(xian)(xian)(xian)）、中(zhong)性(xing)(xing)(xing)線(xian)(xian)(xian)(xian)（零線(xian)(xian)(xian)(xian)）、接(jie)(jie)(jie)地(di)(di)(di)(di)(di)線(xian)(xian)(xian)(xian)。當(dang)(dang)用戶按(an)規定(ding)接(jie)(jie)(jie)好線(xian)(xian)(xian)(xian)后(hou)，用電(dian)筆(bi)(bi)測(ce)試(shi)相線(xian)(xian)(xian)(xian)時，電(dian)筆(bi)(bi)會(hui)發亮(liang)(liang)；而測(ce)中(zhong)性(xing)(xing)(xing)線(xian)(xian)(xian)(xian)及(ji)接(jie)(jie)(jie)地(di)(di)(di)(di)(di)線(xian)(xian)(xian)(xian)時電(dian)筆(bi)(bi)不(bu)會(hui)發亮(liang)(liang)。這(zhe)是因為人體相當(dang)(dang)于(yu)一個(ge)電(dian)容（當(dang)(dang)然電(dian)容很(hen)小）。當(dang)(dang)電(dian)筆(bi)(bi)測(ce)相線(xian)(xian)(xian)(xian)時，相當(dang)(dang)于(yu)相線(xian)(xian)(xian)(xian)對地(di)(di)(di)(di)(di)有只(zhi)電(dian)容，交流電(dian)通過電(dian)容構成(cheng)(cheng)回路，電(dian)筆(bi)(bi)發亮(liang)(liang)。而電(dian)筆(bi)(bi)測(ce)中(zhong)性(xing)(xing)(xing)線(xian)(xian)(xian)(xian)及(ji)接(jie)(jie)(jie)地(di)(di)(di)(di)(di)線(xian)(xian)(xian)(xian)時，因變(bian)壓器中(zhong)性(xing)(xing)(xing)線(xian)(xian)(xian)(xian)都接(jie)(jie)(jie)地(di)(di)(di)(di)(di)，并按(an)規定(ding)重復接(jie)(jie)(jie)地(di)(di)(di)(di)(di)，中(zhong)性(xing)(xing)(xing)線(xian)(xian)(xian)(xian)對地(di)(di)(di)(di)(di)沒(mei)有電(dian)位差，故也不(bu)可能構成(cheng)(cheng)回路，當(dang)(dang)然電(dian)筆(bi)(bi)不(bu)亮(liang)(liang)。

另一(yi)(yi)(yi)種情況，當把護套(tao)線(xian)其(qi)中一(yi)(yi)(yi)根與(yu)相線(xian)連接而其(qi)余線(xian)兩(liang)頭懸空，這(zhe)是用電(dian)(dian)筆測這(zhe)些懸空線(xian)時，電(dian)(dian)筆就會發(fa)亮(liang)。因為(wei)護套(tao)線(xian)里面芯子線(xian)相距很近，相當于一(yi)(yi)(yi)個電(dian)(dian)容；反之，電(dian)(dian)容越小，電(dian)(dian)筆亮(liang)度越暗(an)。這(zhe)是感應電(dian)(dian)的一(yi)(yi)(yi)種現象，與(yu)漏(lou)電(dian)(dian)、短路完全是兩(liang)碼(ma)事，一(yi)(yi)(yi)般不會對人體造成傷害，更不是電(dian)(dian)線(xian)質量問題。

根(gen)據國家(jia)標準，對每根(gen)絕(jue)緣線芯必須進行高壓火花試驗，不同絕(jue)緣厚度(du)規(gui)定(ding)不同試驗電壓值，其中2.5mm2及以(yi)(yi)下截面電線的試驗電壓為交流6000伏，是(shi)實際電壓（220伏）的27倍，所以(yi)(yi)說一(yi)般是(shi)不會有(you)什(shen)么問題。

需(xu)要強(qiang)調指(zhi)出的是(shi)：必(bi)須(xu)請有一定資格(ge)的電(dian)氣專(zhuan)業(ye)人員(yuan)布線(xian)，并嚴(yan)格(ge)按照規(gui)定施工，要防止、杜絕電(dian)線(xian)、電(dian)器漏電(dian)、超載(zai)、短(duan)路現象(xiang)，要盡量采用(yong)漏電(dian)保(bao)護、接(jie)地(di)保(bao)護等措施，以保(bao)證用(yong)電(dian)安全。