浅谈四极开关的选用

On the Selection of a Four-pole Switch

针对不同的接地形式,依据现行规范,介绍了四极开关的选择:1.IT系统有中性线引出时,应采用四极开关;2.TT系统应在隔离相线的同时隔离中性线;3.在TN-C系统中必须选用三极开关;4.TN-S系统可选用四极开关,但是开关的N极只能接N线,而不能接PEN或PE线,在有总等电位联结的TN-S系统中建筑物内不必为电气检修安全而隔离中性线;5.在TN-C-S系统的建筑物内不必为电气检修安全而装设四极开关。

For different grounding forms, according to the existing norms, this paper introduces the four-pole switch selection： 1.IT system neutral wire leads, should be a four-pole switch; 2.TT system should be isolated from neutral phase, while in isolation line; 3. TN-C systems must use three-pole switch; 4.TN-S system can use four-pole switch, but the switch can only take N N pole line, but can not connect PEN or PE line, the TN-S system with other potential join is not necessary for the safety and maintenance of electrical isolation within a building neutral line; 5. TN-C-S system is not necessary to install four-pole switch for the safety maintenance of electricity.