Schneider Electric – IMD‑IM20‑H Vigilohm IM20‑H – Insulation Monitoring Device

The IMD‑IM20‑H (Vigilohm IM20‑H) from Schneider Electric is a precision insulation monitoring device (IMD) designed for ungrounded (IT) systems, including medical and industrial applications. It continuously measures insulation resistance via low-frequency AC injection, features threshold-based alarm logging, transformer load/temperature monitoring, and RS‑485 Modbus communication. DIN-rail or panel-mountable with a 110–230 VAC power supply.  

 Key Specifications

• Model / P/N: IMD‑IM20‑H (Vigilohm IM20‑H)

• Supply Voltage: 110–230 VAC ±15%, 12 VA consumption  

• Measurement Range: Insulation resistance 1 kΩ–10 MΩ

• Test Current: Low-frequency AC injection, ≤ 0.2 mA at 25 V  

• Alarm Threshold: Configurable 50–500 kΩ, <1 s response  

• Transformer Monitoring: Secondary CT input for transformer load and temperature (bimetal)  

• Communication: RS‑485 Modbus RTU interface  

• Relay Output: 1 SPDT relay (6 A @ 250 VAC/DC)  

• Display & LEDs: Digital screen plus “ON” and “Insulation Alarm” LEDs  

• Mounting: DIN rail (clip-on) or panel with spring clips; IP52 front, IP20 rear  

• Operating Temps: –25…+55 °C; housing size: 110×96×59 mm; weight ≈ 250 g