在0類和1類醫(yi)(yi)院場(chang)所(suo)，由于無醫(yi)(yi)院設(she)(she)備(bei)使(shi)用(yong)(yong)(yong)，或相(xiang)關(guan)設(she)(she)備(bei)僅使(shi)用(yong)(yong)(yong)在人體些非致命(ming)部位(wei)，所(suo)以可(ke)(ke)使(shi)用(yong)(yong)(yong)普(pu)通建欽物的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)漂源各(ge)和漏(lou)(lou)(lou)電(dian)(dian)(dian)(dian)(dian)(dian)保護(hu)措(cuo)施。一(yi)般采(cai)用(yong)(yong)(yong)TN系統(tong)(tong)或系統(tong)(tong)，并配備(bei)剩余電(dian)(dian)(dian)(dian)(dian)(dian)流保護(hu)設(she)(she)備(bei)RCD，當發生漏(lou)(lou)(lou)電(dian)(dian)(dian)(dian)(dian)(dian)流超(chao)過30mA的(de)(de)漏(lou)(lou)(lou)電(dian)(dian)(dian)(dian)(dian)(dian)事故(gu)時，RCD動作，分(fen)斷(duan)(duan)故(gu)障回路。這樣即使(shi)造成醫(yi)(yi)院設(she)(she)備(bei)斷(duan)(duan)電(dian)(dian)(dian)(dian)(dian)(dian)，也不(bu)會(hui)對(dui)患(huan)者(zhe)造成重(zhong)大影響，醫(yi)(yi)生的(de)(de)診斷(duan)(duan)也可(ke)(ke)重(zhong)新開始(shi)。IT系統(tong)(tong)作用(yong)(yong)(yong)：降(jiang)低出(chu)點電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)和電(dian)(dian)(dian)(dian)(dian)(dian)網對(dui)地(di)漏(lou)(lou)(lou)電(dian)(dian)(dian)(dian)(dian)(dian)流（有效(xiao)控制對(dui)心臟的(de)(de)直(zhi)接(jie)(jie)(jie)漏(lou)(lou)(lou)電(dian)(dian)(dian)(dian)(dian)(dian)），故(gu)人身觸電(dian)(dian)(dian)(dian)(dian)(dian)危險被降(jiang)到(dao)低程度(du)。可(ke)(ke)以防止接(jie)(jie)(jie)地(di)系統(tong)(tong)內漏(lou)(lou)(lou)電(dian)(dian)(dian)(dian)(dian)(dian)流竄入某些與患(huan)者(zhe)連接(jie)(jie)(jie)的(de)(de)醫(yi)(yi)用(yong)(yong)(yong)電(dian)(dian)(dian)(dian)(dian)(dian)器設(she)(she)備(bei)的(de)(de)對(dui)地(di)回路，從而避免漏(lou)(lou)(lou)電(dian)(dian)(dian)(dian)(dian)(dian)對(dui)患(huan)者(zhe)安全所(suo)構成的(de)(de)威脅。該系統(tong)(tong)還可(ke)(ke)以避免漏(lou)(lou)(lou)電(dian)(dian)(dian)(dian)(dian)(dian)導致系統(tong)(tong)短路器或熔斷(duan)(duan)器動作，保證用(yong)(yong)(yong)電(dian)(dian)(dian)(dian)(dian)(dian)的(de)(de)持續性(xing)和可(ke)(ke)靠性(xing)。一(yi)般用(yong)(yong)(yong)于不(bu)允(yun)許(xu)停電(dian)(dian)(dian)(dian)(dian)(dian)的(de)(de)場(chang)所(suo)，或者(zhe)是要求(qiu)嚴格地(di)連續供電(dian)(dian)(dian)(dian)(dian)(dian)的(de)(de)地(di)方，醫(yi)(yi)院的(de)(de)手術室和ICU室等二類場(chang)所(suo)要采(cai)用(yong)(yong)(yong)IT系統(tong)(tong)。采(cai)用(yong)(yong)(yong)醫(yi)(yi)用(yong)(yong)(yong)隔離(li)電(dian)(dian)(dian)(dian)(dian)(dian)源(IT)系統(tong)(tong)，即電(dian)(dian)(dian)(dian)(dian)(dian)源中性(xing)點不(bu)接(jie)(jie)(jie)地(di)，一(yi)旦(dan)設(she)(she)備(bei)漏(lou)(lou)(lou)電(dian)(dian)(dian)(dian)(dian)(dian)，單(dan)相(xiang)對(dui)地(di)漏(lou)(lou)(lou)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流很小，不(bu)會(hui)破壞電(dian)(dian)(dian)(dian)(dian)(dian)源電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)的(de)(de)平(ping)衡，所(suo)以比電(dian)(dian)(dian)(dian)(dian)(dian)源中性(xing)點接(jie)(jie)(jie)地(di)的(de)(de)系統(tong)(tong)安全、可(ke)(ke)靠。

醫用(yong)IT系(xi)統(tong)(tong)：IT系(xi)統(tong)(tong)保護(hu)(hu)接(jie)(jie)地(di)(di)是指將(jiang)電(dian)氣裝(zhuang)置正(zheng)常情(qing)況(kuang)下(xia)不帶電(dian)的(de)金(jin)屬部(bu)分與接(jie)(jie)地(di)(di)裝(zhuang)置連接(jie)(jie)起來，以防止該部(bu)分在故(gu)障情(qing)況(kuang)下(xia)突然(ran)帶電(dian)而(er)造成對(dui)人體(ti)(ti)(ti)的(de)傷害而(er)設備的(de)金(jin)屬外殼有(you)了(le)保護(hu)(hu)接(jie)(jie)地(di)(di)后，由于人體(ti)(ti)(ti)電(dian)阻(zu)遠比接(jie)(jie)地(di)(di)裝(zhuang)置的(de)接(jie)(jie)地(di)(di)電(dian)阻(zu)大(da)，在發(fa)生單相碰殼時(shi)，大(da)部(bu)分的(de)接(jie)(jie)地(di)(di)電(dian)流被接(jie)(jie)地(di)(di)裝(zhuang)置分流，流經(jing)人體(ti)(ti)(ti)的(de)電(dian)流很(hen)小，從而(er)對(dui)人身安全起了(le)保護(hu)(hu)作用(yong)。IT系(xi)統(tong)(tong)適用(yong)于環境條件不良(liang)，易發(fa)生單相接(jie)(jie)地(di)(di)故(gu)障的(de)場所。

因此對(dui)電(dian)(dian)(dian)氣安全設計也提(ti)出了(le)特殊的(de)(de)(de)要(yao)(yao)求(qiu)。手術室、ICU、CCU病房(fang)等這(zhe)些(xie)對(dui)電(dian)(dian)(dian)力可(ke)靠性要(yao)(yao)求(qiu)很(hen)高的(de)(de)(de)場所(suo)，不(bu)管(guan)出現任何情況，都應保證電(dian)(dian)(dian)力供應的(de)(de)(de)連續性和(he)預防微(wei)電(dian)(dian)(dian)，it接地系(xi)統(tong)，否(fou)則(ze)，將導致因維持生命的(de)(de)(de)設備斷(duan)電(dian)(dian)(dian)或漏電(dian)(dian)(dian)而對(dui)患(huan)者造(zao)成生命危險。一般供電(dian)(dian)(dian)電(dian)(dian)(dian)網(wang)是(shi)(shi)以大地作為(wei)參考電(dian)(dian)(dian)位，相線中(zhong)的(de)(de)(de)電(dian)(dian)(dian)流(liu)可(ke)以通(tong)過任何未絕緣的(de)(de)(de)通(tong)道，對(dui)地構成回路(lu)，這(zhe)是(shi)(shi)的(de)(de)(de)根本原因。隔(ge)(ge)離供電(dian)(dian)(dian)是(shi)(shi)采用(yong)(yong)隔(ge)(ge)離變壓器(qi)供電(dian)(dian)(dian)，電(dian)(dian)(dian)源(yuan)經隔(ge)(ge)離變壓器(qi)隔(ge)(ge)離后，原電(dian)(dian)(dian)網(wang)中(zhong)的(de)(de)(de)地已不(bu)再(zai)是(shi)(shi)參考電(dian)(dian)(dian)位。該系(xi)統(tong)接地故障多為(wei)金屬性短路(lu)，因故障電(dian)(dian)(dian)流(liu)較大，使(shi)斷(duan)路(lu)器(qi)或熔斷(duan)器(qi)等過電(dian)(dian)(dian)流(liu)保護裝置動作，造(zao)成房(fang)間(jian)停電(dian)(dian)(dian)。顯然(ran)TN—S系(xi)統(tong)不(bu)能滿(man)足醫院中(zhong)一些(xie)重要(yao)(yao)場所(suo)對(dui)不(bu)間(jian)斷(duan)供電(dian)(dian)(dian)的(de)(de)(de)實用(yong)(yong)要(yao)(yao)求(qiu)