标准IEC 60364-5-53规定，出于维修原因，尤其是涉及安全的情况下，可能需要区分串联安装的剩余电流保护装置，以便为未涉及故障的安装部件（如有）提供供电连续性。可以通过选择和安装RCD来实现这种区分，以便通过靠近故障的RCD断开电源。RCD之间有两种类型的区分：-水平区分：通过使用专用剩余电流断路器为每条线路提供保护；这样，在接地故障的情况下，只有故障线路断开，因为其他RCD没有检测到任何故障电流。然而，有必要提供保护措施，防止配电盘部分和RCD上游电厂的间接接触；-垂直辨别：通过使用串联的RCD实现。图2:RCD 4.7电容电流装置（RCD）458电气装置之间的水平区分| ABB 4根据IEC 60364-5-53对人体的保护，以确保串联的两个剩余电流保护装置之间的区分，这些装置应满足以下两个条件：-位于电源侧（上游）的剩余电流保护装置的非动作时间-电流特性应高于位于负载侧（下游）的剩余电流保护装置的总动作时间-电流特性位于电源侧的装置上的额定剩余工作电流应高于位于负载侧的剩余电流保护装置的额定剩余工作电流。非动作时间-电流特性是报告大时间值的曲线，在此期间，剩余电流大于剩余非动作电流（等于0.5.I∆n）涉及剩余电流断路器，但不会导致跳闸。综上所述，可以对串联的两个RCD进行区分：-对于位于电源侧的S型剩余电流断路器（符合IEC 61008-1和IEC 61009），通过选择位于下游的通用型断路器，使用I∆n等于I的三分之一∆上游的n个；-对于电子剩余电流释放，通过选择时间和电流阈值直接大于下游装置的上游装置，仔细考虑公差。对于TT系统中配电电路中的间接触点保护，I∆n不得超过1s（IEC 60364-4-41，第411.3.2.4段）

The Standard IEC 60364-5-53 states that discrimination between residual current protective devices installed in series may be required for service reasons, particularly when safety is involved, to provide continuity of supply to the parts of the installation not involved by the fault, if any. This discrimination can be achieved by selecting and installing RCDs in order to provide the disconnection from the supply by the RCD closest to the fault. There are two types of discrimination between RCDs: - horizontal discrimination: it provides the protection of each line by using a dedicated residual current circuit-breaker; in this way, in case of earth fault, only the faulted line is disconnected, since the other RCDs do not detect any fault current. However, it is necessary to provide protective measures against indirect contacts in the part of the switchboard and of the plant upstream the RCD; - vertical discrimination: it is realized by using RCDs connected in series. Figure 2: Horizontal discrimination between RCDs 4.7 Resiual current devices (RCDs) 458 Electrical devices | ABB 4 Protection of human beings According to IEC 60364-5-53, to ensure discrimination between two residual current protective devices in series, these devices shall satisfy both the following conditions: - the non-actuating time-current characteristic of the residual current protective device located on the supply side (upstream) shall lie above the total operating time-current characteristic of the residual current protective device located on the load side (downstream); - the rated residual operating current on the device located on the supply side shall be higher than that of the residual current protective device located on the load side. The non-actuating time-current characteristic is the curve reporting the maximum time value during which a residual current greater than the residual non-operating current (equal to 0.5.I ∆n ) involves the residual current circuitbreaker without causing the tripping. As a conclusion, discrimination between two RCDs connected in series can be achieved: - for S type residual current circuit-breakers, located on the supply side, (complying with IEC 61008-1 and IEC 61009), time-delayed type, by choosing general type circuit-breakers located downstream with I∆n equal to one third of I∆n of the upstream ones; - for electronic residual current releases by choosing the upstream device with time and current thresholds directly greater than the downstream device, keeping carefully into consideration the tolerances. For the protection against indirect contacts in distribution circuits in TT system, the maximum disconnecting time at I∆n shall not exceed 1 s (IEC 60364-4-41, par. 411.3.2.4)