IEC 61557-4:2019
交流1000V和直流1500V以下低压配电系统的电气安全保护措施的试验、测量或监测设备第4部分:接地连接和等电位连接的电阻
Electrical safety in low voltage distribution systems up to 1 000 V AC and 1 500 V DC - Equipment for testing, measuring or monitoring of protective measures - Part 4: Resistance of earth connection a