Product Overview
The ABB CM-IWS.2S continuously monitors insulation resistance in unearthed IT AC electrical systems. It detects deterioration between the live conductors and earth before the insulation fault develops into equipment damage, fire risk or an unexpected electrical shutdown.
This function is important aboard vessels and offshore installations, where electrical systems often use unearthed distribution to maintain continuity after the first earth fault.
Technical Specifications
| Specification | Details |
|---|---|
| Manufacturer | ABB |
| Model | CM-IWS.2S |
| Full part number | 1SVR730670R0200 |
| Product type | Insulation-monitoring relay |
| Monitored network | Unearthed IT AC systems |
| Monitored system voltage | Up to 400 V AC |
| Control supply | 24–240 V AC/DC |
| Supply frequency | 50/60 Hz |
| Adjustable insulation range | 1–100 kΩ |
| Output | 1 changeover contact, SPDT |
| Contact rating | 4 A conventional thermal current |
| Operating principle | Closed-circuit/fail-safe principle |
| Indication | Three front status LEDs |
| Controls | Test/reset button and threshold adjustments |
| Connection | Screw terminals |
| Installation | DIN-rail mounting |
| Product width | 22.5 mm |
| Dimensions | Approximately 22.5 × 85.6 × 103.7 mm |
| Net weight | Approximately 0.141 kg |
| Front protection | IP20 |
| Operating temperature | Approximately −25°C to +60°C |
| Monitoring standard | IEC/EN 61557-8 |
Main Functions
- Continuous insulation-resistance monitoring
- Adjustable alarm threshold
- Automatic detection of insulation deterioration
- Monitoring of single-phase and three-phase control circuits
- Test and reset facility
- LED operating and fault indication
- Output contact for alarms, PLCs or ship alarm-monitoring systems
- Closed-circuit operating principle for fail-safe fault reporting
- Compact DIN-rail installation
Marine and Offshore Applications
- Main and emergency switchboards
- Unearthed shipboard power systems
- Generator control panels
- Motor-control centres
- Thruster control systems
- Steering-gear electrical panels
- Pump and compressor control panels
- Offshore drilling equipment
- Crane and winch control panels
- Engine-room auxiliary machinery
- Navigation and communication power panels
- Battery-charger and UPS distribution panels
