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通常低压电气装置的接地保护方式分为保护接零(TN-C系统)和保护接地(TT系统)两种。我国居民住宅的供用电线路大都是380/220V中性点直接接地网络,在这个网络中,接零或接地实质上都是与大地作良好的电气连接,但它们具有不同的概念,具体做法也有很大的区别。什么情况下接零,什么情况下接地,过去没有统一的强制性规定。因此常常因接地保护不当而发生事故。那么在居民住宅中接地保护方式究竟应该采用保护接零还是保护接地呢? 以往推荐采用保护接零主要是因为当时触电保安器尚不够成熟,未曾广泛使用。在没有触电保安器的情况下采用保护接零比采用保护接地有较大的优越性,其中最突出的就是不装触电保安器仍
Generally, the grounding protection of low-voltage electrical devices is classified into two types: protective zero (TN-C system) and protective ground (TT system). Most residential power supply and supply lines in China are 380/220V neutral grounded direct grounding networks. In this network, grounding or grounding is essentially a good electrical connection to the earth, but they have different concepts. There is also a big difference. Under what circumstances is it connected to zero and under what circumstances grounding has not been unified in the past. Therefore, accidents often occur due to improper grounding protection. Then, in the residential house, should the grounding protection method adopt zero protection or protective grounding? In the past, it was mainly recommended that the zero-crossing protection was not mature enough and was not widely used. In the absence of electric shock protectors, the use of protective zero is more advantageous than the use of protective grounding, the most prominent of which is the absence of electric shock protectors.