Insulation Fault Detection Solution – BENDER IRDH275B-427 | IR Series
Where This Product Is Used
The BENDER IRDH275B-427 is an insulation monitoring device (IMD) engineered for ungrounded IT power systems where continuous operation is mission-critical. Engineers and system integrators specify this device across the following environments:
- Medical Facilities (OR & ICU): Monitors insulation resistance in isolated power systems (IPS) per IEC 61557-8, ensuring patient safety and compliance with IEC 60364-7-710.
- Marine & Offshore Platforms: Protects shipboard IT networks from insulation degradation caused by humidity, salt spray, and vibration.
- Industrial Automation & Process Control: Monitors PLC control panels, servo drive cabinets, and variable frequency drive (VFD) enclosures for early insulation faults before production downtime occurs.
- Renewable Energy & EV Charging Infrastructure: Deployed in photovoltaic (PV) inverter systems and EV charging stations to detect ground faults in floating DC/AC networks.
- Data Centers & UPS Systems: Provides continuous insulation monitoring on critical UPS output circuits to prevent unplanned outages.
- Railway & Transportation: Used in traction power systems and rolling stock where IT network integrity is mandatory.
Technical Specifications
| Parameter | Value |
|---|---|
| Model | IRDH275B-427 |
| Brand / Manufacturer | BENDER GmbH & Co. KG |
| Series | IR Series (IRDH275B) |
| Function | Insulation Monitoring Device (IMD) for IT Systems |
| Nominal System Voltage (Un) | Up to AC 690 V / DC 1000 V |
| Measuring Voltage | DC measuring voltage superimposed on AC system |
| Response Value (Alarm) | 1 kΩ – 10 MΩ (adjustable) |
| Measuring Range | 1 kΩ – ∞ (open circuit) |
| Supply Voltage | AC/DC 24–240 V (universal) |
| Output Relays | 2 × changeover contacts (alarm + fault) |
| Communication Interface | RS-485 / Modbus RTU (optional) |
| Display | LCD with backlight, insulation value readout |
| Protection Class | IP30 (front panel IP40 with cover) |
| Operating Temperature | -25 °C to +70 °C |
| Mounting | DIN rail (35 mm) or panel mount |
| Approvals | CE, UL, cUL, GL, DNV |
| Weight | Approx. 500 g |
| Part Number / SKU | IRDH275B-427 |
Why Engineers Specify This Model
- Continuous Monitoring Without System Shutdown: The IRDH275B-427 monitors insulation resistance 24/7 without interrupting the live IT system — critical for hospitals and process plants where downtime is not an option.
- Wide Voltage Range: A single device covers AC and DC systems up to 690 V AC / 1000 V DC, reducing SKU complexity in multi-voltage installations.
- Adjustable Alarm Thresholds: Response values from 1 kΩ to 10 MΩ allow engineers to tune sensitivity to the specific insulation class of their installation.
- Dual Relay Output: Separate pre-alarm and main alarm relays enable staged response — alert maintenance before triggering a full system shutdown.
- Modbus RTU Integration: Native RS-485 support allows direct integration with SCADA, BMS, and PLC systems for remote monitoring and data logging.
- Proven BENDER Pedigree: BENDER has been the global reference standard for insulation monitoring since 1946. The IRDH275B series is installed in thousands of critical facilities worldwide.
Complete System Bill of Materials
For a complete insulation monitoring system, engineers typically pair the IRDH275B-427 with:
- Coupling Device: BENDER AGE series (for high-capacitance systems)
- Insulation Fault Locator: BENDER EDS series (to pinpoint fault location after alarm)
- Remote Annunciator Panel: BENDER BMS series display unit
- DIN Rail Power Supply: 24 VDC SMPS (if supply voltage conversion required)
- RS-485 to USB Converter: For commissioning and parameter configuration via PC
- Shielded Twisted Pair Cable: For Modbus RTU wiring (≤1000 m bus length)
Compliance & Industry Standards
- IEC 61557-8 — Insulation monitoring devices for IT systems
- IEC 60364-7-710 — Electrical installations in medical locations
- IEC 60364-4-41 — Protection against electric shock
- DIN VDE 0100-710 — Medical locations (German standard)
- NFPA 99 — Health Care Facilities Code (USA)
- DNV GL — Marine & Offshore type approval
- CE Marking — EU Low Voltage Directive & EMC Directive
- UL / cUL Listed — North American market compliance
Quality Assurance & Sourcing
Konmask.com sources the BENDER IRDH275B-427 exclusively through verified distribution channels. Every unit undergoes the following before dispatch:
- Visual inspection for physical damage and label integrity
- Serial number verification against manufacturer records
- Functional power-on test confirming display and relay operation
- Original manufacturer packaging and documentation included
- Certificate of conformity available upon request
We do not supply grey-market, refurbished, or counterfeit components. All products carry the original BENDER warranty.
How to Source This Part
- In Stock: Order directly via this product page for same-day processing.
- Lead Time Orders: Contact us for bulk quantity pricing and scheduled delivery.
- OEM / Project Quotation: Email support@konmask.com with your BOM and project timeline.
- Export & International Shipping: We ship globally. DDP (Delivered Duty Paid) terms available for select regions.
- Urgent Requirement: Call +0086 19859288691 for expedited sourcing.
Application-Specific FAQ
Q: Can the IRDH275B-427 monitor both AC and DC IT systems?
A: Yes. The device uses a superimposed DC measuring voltage that is compatible with both AC and DC ungrounded (IT) systems up to 690 V AC / 1000 V DC.
Q: Is this device suitable for medical IT systems per IEC 60364-7-710?
A: Yes. The IRDH275B series is specifically designed and certified for use in medical IT systems (operating theatres, ICUs) and meets the requirements of IEC 61557-8 and IEC 60364-7-710.
Q: What happens when an insulation fault is detected?
A: The device activates its alarm relay and displays the measured insulation resistance value on the LCD. If Modbus RTU is connected, the alarm status and resistance value are transmitted to the SCADA/PLC system in real time.
Q: Can I adjust the alarm threshold on-site?
A: Yes. The response value (alarm threshold) is adjustable from 1 kΩ to 10 MΩ via the front panel controls, without requiring a PC or software tool.
Q: Does the IRDH275B-427 work with capacitive systems (e.g., VFD-heavy installations)?
A: Yes, but for systems with high leakage capacitance (common in VFD-heavy plants), BENDER recommends pairing the IRDH275B-427 with an AGE coupling device to maintain measurement accuracy.
Q: What is the difference between IRDH275B-427 and IRDH275B-435?
A: The suffix (-427, -435, etc.) denotes the supply voltage variant. The -427 variant accepts AC/DC 24–240 V universal supply. Always verify the suffix matches your panel supply voltage before ordering.
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