The insulation fault locators ISOSCAN® EDS440/441 are used in with the ISOMETER® iso685-D-
P or the locating current injector PGH to locate insulation faults in unearthed power supply
systems (IT systems). The EDS440/441 detect locating current signals generated by the
insulation monitoring device iso685-D-P or IRDH575 or the locating current injector PGH. Up to
12 measuring current transformers can be connected to an EDS44x. In total, up to 21 insulation 
fault locators can be connected via an RS-485 interface (BS bus protocol) and thereby up to
252 outgoing circuits can be monitored.

Product Details


  • Universal system concept
  • Modular design, therefore easily adjustable to the given circumstances
  • Measuring current transformers available in various sizes and versions
  • CT connection monitoring
  • 12 measuring channels for measuring current transformer series W…, WR…, WS…
  • Fault memory behaviour selectable
  • Configuration possibilities enable individual adjustments
  • Up to 21 EDS insulation fault locators in the system, 252 measuring channels
  • Response sensitivity 2…10 mA
  • AC residual current measurement with configurable response value
  • Two alarm relays with one N/O contact each
  • N/O or N/C operation selectable
  • External test/reset button via digital inputs
  • Indication via iso685-D-P or LEDs
  • Central indication of faulty outgoing circuits
  • Serial interface RS-485, BS bus address range 2…90
  • Connection to higher-level control and visualisation systems possible


  • Insulation fault location in AC, 3AC and DC IT systems
  • Main circuits and control circuits in industrial plants and ships
  • Diode-decoupled DC IT systems in power plants
  • Systems for medical locations