What is an insulation monitoring device (IMD)?
The insulation monitoring device's role, its relationship with distribution system type and points to consider during product selection.
Go to related Bender models ↓What does an IMD monitor?
IMD stands for ‘Insulation Monitoring Device’. An IMD continuously monitors the insulation resistance of live conductors to earth in unearthed IT systems. It generates an alarm when the measured resistance falls below the configured threshold. Changes in insulation level over time help assess the condition of the electrical infrastructure.
What is an IT system?
IT here does not mean information technology; it describes the electrical distribution system's earthing arrangement. Before selecting an IMD, verify that the system is suitable for this monitoring approach. Do not assume every circuit in the same installation has the same earthing arrangement.
Are IMD and residual current monitoring the same?
Insulation monitoring tracks insulation resistance in an IT system. Residual current monitors (RCM/RCMS) are assessed for monitoring residual currents in earthed TN and TT circuits. The measured quantities and operating conditions differ. Suitability as a replacement cannot be determined by product names alone.
Why is fault location a separate function?
Falling insulation resistance produces an alarm, but identifying the faulty circuit is a separate question. In compatible IT systems, ISOSCAN® / EDS components support insulation fault location. The relevant test current source and measuring components must be assessed together for this function.
How do you choose a Bender insulation monitoring device?
First establish the AC/DC configuration, nominal system voltage and system leakage capacitance. Then assess the application, communication, alarm and mounting requirements. Industrial, PV, railway and medical products have different technical scopes. Verify final model and variant selection against the current Bender datasheet.
Product information and supply in Türkiye
As Bender's distributor in Türkiye, ADEO Teknik offers technical product selection information, access to manufacturer documents and quotation support. Including the distribution system type, system voltage and application in your enquiry helps identify the suitable product family.
Bender IMD models by application conditions
Different products serve control circuits, industrial IT main circuits and large PV installations. Compare voltage, system leakage capacitance, connected power electronics and fault location needs on their model pages.
ISOMETER® iso415R
Monitors insulation resistance in unearthed AC/DC control circuits, with parameter access via Modbus RTU and NFC.
Voltage range depends on the variant; use in small main circuits is assessed against the manufacturer's limitation to applications without VFDs.Explore the model and documents
ISOMETER® iso685…
Offers different measuring profiles for IT systems that may contain rectifiers, inverters and drives; monitors insulation resistance and relevant system quantities.
Match the AC/DC configuration, Ce and voltage limits to the suitable profile; consider the P variant separately if fault location is required.Explore the model and documents
ISOMETER® isoPV1685DP
Developed for large PV installations configured as IT systems, with adaptation to high system leakage capacitance and an integrated locating current source.
The AC 1000 V/DC 1500 V and 4000 µF limits apply to this model. Compatible EDS equipment and current transformers are required for feeder-level fault location.Explore the model and documentsThese models are a starting point for selection; they are not interchangeable in every application. Product images belong to Bender.
Bender sources for these models
Technical source: Official Bender product information ↗