該系統(tong)接地(di)故障多(duo)為金屬性短路，因故障電(dian)流較大(da)，使斷路器或(huo)熔斷器等過(guo)電(dian)流保護裝置動作，造(zao)成房(fang)(fang)間(jian)停電(dian)。顯然TN—S系統(tong)不能滿(man)足醫院(yuan)中(zhong)一些(xie)重(zhong)要(yao)場所(suo)對不間(jian)斷供電(dian)的實用(yong)要(yao)求。故醫院(yuan)2類場所(suo)：如中(zhong)心(xin)手(shou)術部的所(suo)有手(shou)術室I所(suo)有CU病房(fang)(fang)(包(bao)括ICU，CCU，NICU，PICU，SICU等)和心(xin)臟(zang)導管介入(ru)室等，應當(dang)采用(yong)醫用(yong)隔離電(dian)源(IT)系統(tong)供電(dian)。

隨(sui)著電子醫(yi)院設(she)(she)備(bei)(bei)在醫(yi)院領域的(de)(de)(de)廣泛應(ying)用(yong)，漏(lou)電流對(dui)患(huan)者(zhe)(zhe)構(gou)成的(de)(de)(de)威(wei)脅(xie)也(ye)越(yue)來越(yue)大，尤其是那些生命攸關的(de)(de)(de)場(chang)(chang)所(suo)，患(huan)者(zhe)(zhe)在手術(shu)中或麻(ma)藥狀態下(xia)，各(ge)種傳感(gan)器直(zhi)接(jie)插入(ru)人體內，微小的(de)(de)(de)漏(lou)電流都有可(ke)能導致患(huan)者(zhe)(zhe)觸電身亡。另外有些醫(yi)院設(she)(she)備(bei)(bei)用(yong)于(yu)維持(chi)患(huan)者(zhe)(zhe)的(de)(de)(de)生命，一旦設(she)(she)備(bei)(bei)停電，也(ye)會對(dui)患(huan)者(zhe)(zhe)的(de)(de)(de)生命構(gou)成威(wei)脅(xie)。因(yin)此，對(dui)于(yu)醫(yi)院這一特殊場(chang)(chang)所(suo)的(de)(de)(de)電氣設(she)(she)計，應(ying)嚴格按照和規范要(yao)求，采用(yong)IT系統(tong)供電。

IT系(xi)(xi)統(tong)(tong)作(zuo)用(yong)(yong)(yong)：降低出點(dian)電(dian)(dian)(dian)(dian)(dian)(dian)壓和(he)電(dian)(dian)(dian)(dian)(dian)(dian)網對地(di)(di)(di)(di)漏(lou)(lou)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)（有(you)效(xiao)控制對心臟(zang)的(de)直接(jie)(jie)(jie)漏(lou)(lou)電(dian)(dian)(dian)(dian)(dian)(dian)），故人身觸(chu)電(dian)(dian)(dian)(dian)(dian)(dian)危(wei)險被降到低程度(du)。可以(yi)防止接(jie)(jie)(jie)地(di)(di)(di)(di)系(xi)(xi)統(tong)(tong)內漏(lou)(lou)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)竄入某些與(yu)患者連(lian)接(jie)(jie)(jie)的(de)醫用(yong)(yong)(yong)電(dian)(dian)(dian)(dian)(dian)(dian)器設備(bei)的(de)對地(di)(di)(di)(di)回(hui)路，從而(er)避(bi)免(mian)漏(lou)(lou)電(dian)(dian)(dian)(dian)(dian)(dian)對患者安全所構(gou)成的(de)威(wei)脅。該(gai)系(xi)(xi)統(tong)(tong)還可以(yi)避(bi)免(mian)漏(lou)(lou)電(dian)(dian)(dian)(dian)(dian)(dian)導(dao)致系(xi)(xi)統(tong)(tong)短路器或熔(rong)斷器動作(zuo)，保證用(yong)(yong)(yong)電(dian)(dian)(dian)(dian)(dian)(dian)的(de)持續性和(he)可靠(kao)性。醫用(yong)(yong)(yong)IT供(gong)電(dian)(dian)(dian)(dian)(dian)(dian)系(xi)(xi)統(tong)(tong)由一臺隔(ge)離變(bian)壓器，醫用(yong)(yong)(yong)it系(xi)(xi)統(tong)(tong)多少錢(qian)，一臺絕緣(yuan)電(dian)(dian)(dian)(dian)(dian)(dian)阻，變(bian)壓器溫度(du)與(yu)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)負荷監測設備(bei)和(he)一臺安裝(zhuang)(zhuang)于(yu)手術室或臨近的(de)護士間的(de)操(cao)作(zuo)與(yu)報警終(zhong)端(duan)(duan)組成。IT系(xi)(xi)統(tong)(tong)是(shi)區(qu)分(fen)了三類不同的(de)接(jie)(jie)(jie)地(di)(di)(di)(di)系(xi)(xi)統(tong)(tong) 字母(mu)表示電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)端(duan)(duan)與(yu)地(di)(di)(di)(di)的(de)關系(xi)(xi)：T表示電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)端(duan)(duan)有(you)一點(dian)直接(jie)(jie)(jie)接(jie)(jie)(jie)地(di)(di)(di)(di)；I表示電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)端(duan)(duan)所有(you)帶電(dian)(dian)(dian)(dian)(dian)(dian)部分(fen)不接(jie)(jie)(jie)地(di)(di)(di)(di)或有(you)一點(dian)通過(guo)阻抗接(jie)(jie)(jie)地(di)(di)(di)(di)。第二個字母(mu)表示電(dian)(dian)(dian)(dian)(dian)(dian)氣(qi)裝(zhuang)(zhuang)置(zhi)的(de)外(wai)露可導(dao)電(dian)(dian)(dian)(dian)(dian)(dian)部分(fen)與(yu)地(di)(di)(di)(di)的(de)關系(xi)(xi)：T表示電(dian)(dian)(dian)(dian)(dian)(dian)氣(qi)裝(zhuang)(zhuang)置(zhi)的(de)外(wai)露可導(dao)電(dian)(dian)(dian)(dian)(dian)(dian)部分(fen)直接(jie)(jie)(jie)接(jie)(jie)(jie)地(di)(di)(di)(di)，此接(jie)(jie)(jie)地(di)(di)(di)(di)點(dian)在電(dian)(dian)(dian)(dian)(dian)(dian)氣(qi)上獨立(li)于(yu)電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)端(duan)(duan)的(de)接(jie)(jie)(jie)地(di)(di)(di)(di)點(dian)；表示電(dian)(dian)(dian)(dian)(dian)(dian)氣(qi)裝(zhuang)(zhuang)置(zhi)的(de)外(wai)露可導(dao)電(dian)(dian)(dian)(dian)(dian)(dian)部分(fen)與(yu)電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)端(duan)(duan)接(jie)(jie)(jie)地(di)(di)(di)(di)有(you)直接(jie)(jie)(jie)電(dian)(dian)(dian)(dian)(dian)(dian)氣(qi)連(lian)接(jie)(jie)(jie)。