IT系统特点（不引出中性线），发生第一次接地故障时，接地故障仅为非故障相对地的电容电流，其值很小，外露导电部分对地电压不超过50V，不需要立即切断故障回路，保证供电的连续性；发生接地故障时，对地电压升高1.73倍；220V负载需配降压变压器，或由系统外电源专供；安装绝缘监察器。
The characteristics of IT system (no neutral line is introduced). When the first grounding fault occurs, the grounding fault is only the capacitive current of the non-fault relative ground, and its value is very small. The grounding voltage of the exposed conductive part does not exceed 50V, so the fault circuit does not need to be cut off immediately to ensure the continuity of power supply. When the grounding fault occurs, the grounding voltage rises by 1.73. Double; 220V load need to be equipped with step-down transformer, or exclusively supplied by external power supply; Installation monitor.