The insulation monitoring devices HIG92 produced by HAKEL for the ISOLGUARD series are designed for monitoring the insulation status of single-phase and 3-phase ungrounded IT power supply systems, are designed and operated according to standards IEC 61010-1:2010, EN 50522, IEC 61936-1:2010.
Devices enable monitoring of single-phase and 3-phase ungrounded IT power supplies systems up to the maximum operating voltage 275V AC, eventually 3x275V ACIf the insulation status monitoring of a single-phase or 3-phase ungrounded IT power supply system with higher operating voltage is required, it is necessary to create an artificial centre using TL* inductors produced by HAKEL. Such a created centre is connected to the terminal of insulation monitoring device HIG92.
The insulation monitoring devices enables to display the numeric value of the measured insulation resistance, than there are buttons for setting module parameters and signalling LED diodes for displaying the status of monitored power supply system and of the device. To the insulation monitoring device it is possible to connect MDS10T, MDS-DELTA or MDS-D remote monitoring modules of the monitored power supply system status produced by HAKEL.
HIG91 devices are equipped with RS485 communication line and can communicate with the master computer via industrial RS485 bus with the protocol based on the PROFIBUS protocol. Description of the protocol is available on request.

One or two built-in signalling relays with a switch contact enable the connection of equipment for signalling of alarm. The insulation monitoring device has an optional alarm memory function with the option to cancel the alarm using the button on the insulation monitoring device. Local and remote testing of the function of the insulation monitoring device can also be conducted.

Only one insulation monitoring device can be connected to the same ungrounded IT power supply system.

Basic characteristics

  • Insulation monitoring device for AC systems with 90 to 275 V voltage without additional devices, for greater voltages additional inductor is needed
  • Display of the measured insulation resistance Risol in the range 5 kΩ to 900 kΩ 
  • Two insulating resistance status signalling relays equipped with switching contact
  • Connection to RS485 bus, insulation strength 2500 Vrms against the internal circuits and power supply system circuits
  • Optional memory of the invoked alarm with possibility to unlock by button on the device
  • Option to set two values of monitored insulation resistance Rcrit1 and Rcrit2 using the display and push-buttons, namely in the range from 5 kΩ to 300 kΩ or from 200 kΩ to 900 kΩ according to the type of device
  • Adjustable hysteresis of the insulation resistance limit value in the range from 0 to 100 % using the display and pushbuttons
  • Adjustable delay in signalling relay response tON in the range from 0 to 60 seconds using the display and push-buttons
  • Access to the IMD parameter setting with the pushbuttons can be locked/unlocked by a button combination
  • Separate supply voltage also allows to monitor IT power supply systems, which are not under voltage
  • 2M (36 mm) module width for assembling on DIN rail 35
Dimension drawing
Dimension drawing
Installation diagram
Installation diagram Počet fotek v galerii: 4
Supply voltage range Us 90 ÷ 265 V AC or 90 ÷ 370 V DC
Maximum IT power supply system operating voltage (without external inductor) Un 275 V AC
Power consumption P max. 5 VA
Measuring voltage Um 12 V DC
Measuring current Im < 0,6 mA
Internal resistance of the measuring input Zi > 1 MΩ
Displayed value’s range Risol 200 kΩ ÷ 5MΩ
Measurement accuracy 200 kΩ … 1 MΩ ± 10%
Measurement accuracy 1 MΩ … 5 MΩ ± 15%
Critical insulation resistence Rcrit adjustable 200 kΩ ÷ 900 kΩ
Insulation resistance hysteresis Rhyst adjustable 0 ÷ +100% Rcrit
Delay in response of signalling tON adjustable 0 ÷ 60 sec.
Signalling relay 1/ Signalling potential-free switching contact / Electric strength to the internal circuits and supply circuits 250 V AC / 1A / 3750 Vrms
Remote monitoring Terminals for connection of the MDS10T(+MPS) module produced by Hakel max 5 x MPS10T modules or max 2 MDS10T+MPS modules
RS485 line or MDS-D remote monitoring display module / MDS-DELTA modules from HAKEL production
Communication line: RS485 type MASTER-SLAVE, 9600 Bd, even count parity / Insulating strength to the internal circuits and to the network circuits 2500 Vrms
General data
Degree of protection according to IEC 60529 IP20
Weight m 160 g
Housing material PA-UL94 V0
Method of assembly DIN rail 35
Recommended section of the connected conductors S 1 mm2
Operating temperature ϑ -10°C ~ +60°C
Operating conditions
Atmospheric pressure 86 ÷ 106 kPa
Operating position any
External magnetic and electric field according to IEC 61326-2-4
Overvoltage category / testing voltage III, according to IEC 60664-1:2007
Pollution degree 2, according to IEC 60664-1:2007
Operational mode pernament
Article number 70 913
Installation instructions (219.71 KB)
2D model (728.74 KB) for registered only
3D model (469.2 KB) for registered only
EC declaration of conformity (83.77 KB) for registered only