380伏三相四線(xian)(xian)電(dian)(dian)路中,任(ren)意兩根火線(xian)(xian)之(zhi)間(jian)的(de)電(dian)(dian)壓都是380伏,任(ren)意一根火線(xian)(xian)與零線(xian)(xian)之(zhi)間(jian)都可以組成(cheng)220伏。這(zhe)個(ge)系統可以形(xing)成(cheng)三種電(dian)(dian)源(yuan)(yuan):即單(dan)相220伏電(dian)(dian)源(yuan)(yuan),單(dan)相380伏電(dian)(dian)源(yuan)(yuan),三相380伏電(dian)(dian)源(yuan)(yuan),第 I 種家用(yong)比較多(duo),第三種工廠(chang)里電(dian)(dian)機類用(yong)得(de)多(duo),第二(er)種用(yong)得(de)少(shao),只有交流電(dian)(dian)焊(han)機經常(chang)用(yong)到單(dan)相380伏電(dian)(dian)源(yuan)(yuan)。