380伏(fu)(fu)(fu)三(san)相(xiang)四線(xian)電(dian)(dian)路中,任(ren)意兩根火線(xian)之(zhi)間(jian)(jian)的電(dian)(dian)壓(ya)都是(shi)380伏(fu)(fu)(fu),任(ren)意一根火線(xian)與零(ling)線(xian)之(zhi)間(jian)(jian)都可以(yi)組成220伏(fu)(fu)(fu)。這個系統(tong)可以(yi)形(xing)成三(san)種(zhong)電(dian)(dian)源(yuan)(yuan):即單(dan)相(xiang)220伏(fu)(fu)(fu)電(dian)(dian)源(yuan)(yuan),單(dan)相(xiang)380伏(fu)(fu)(fu)電(dian)(dian)源(yuan)(yuan),三(san)相(xiang)380伏(fu)(fu)(fu)電(dian)(dian)源(yuan)(yuan),第(di) I 種(zhong)家用比較多,第(di)三(san)種(zhong)工廠里電(dian)(dian)機類用得(de)(de)多,第(di)二(er)種(zhong)用得(de)(de)少,只有(you)交流電(dian)(dian)焊機經常用到單(dan)相(xiang)380伏(fu)(fu)(fu)電(dian)(dian)源(yuan)(yuan)。