380伏三相(xiang)四(si)線(xian)電(dian)路中,任(ren)意兩根火(huo)線(xian)之間的(de)電(dian)壓都是380伏,任(ren)意一根火(huo)線(xian)與(yu)零線(xian)之間都可以(yi)組(zu)成220伏。這個系統(tong)可以(yi)形成三種(zhong)電(dian)源(yuan):即單(dan)相(xiang)220伏電(dian)源(yuan),單(dan)相(xiang)380伏電(dian)源(yuan),三相(xiang)380伏電(dian)源(yuan),第(di)(di) I 種(zhong)家用(yong)比較多(duo),第(di)(di)三種(zhong)工廠里電(dian)機類用(yong)得多(duo),第(di)(di)二(er)種(zhong)用(yong)得少,只有交流電(dian)焊機經(jing)常用(yong)到單(dan)相(xiang)380伏電(dian)源(yuan)。