The insulation monitoring devices HIG91/Q and HIG92/Q 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, IEC 61557-8:2007.

Devices enable monitoring of single-phase and 3-phase ungrounded IT power supplies systems up to the maximum operating voltage 275V AC, eventually 3x275V AC. If 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 HIG91/Q or HIG92/Q.

The insulation monitoring devices enable 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

HIG91/Q/485 and HIG92/Q/485 can communicate with the master computer via industrial RS485 bus with the protocol based on the PROFIBUS protocol.

Inbuilt signalling relays with switching contacts enables connection of alarm signalling. The device has an optional alarm memory function with the option to terminate the alarm using the button on the insulation monitoring device. Local and remote testing of the insulation monitoring device function can be done.

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 0 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 or 200 kΩ to 5 MΩ
  • Insulating resistance status signalling relay equipped with switching contact
  • Connection to RS485 bus for versions 485, insulation strength 2500 Vrms against the internal circuits and network circuits
  • Optional memory of the invoked alarm with possibility to unlock by push-button on the device or remote button
  • Option to set monitored insulation resistance Rcrit 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 push-buttons
  • Adjustable delay in signalling relay response tON in the range from 0 to 60 seconds using the display and push-buttons
  • Access to the device parameter setting can be locked, unlocking by a push-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: 2
Supply voltage range Us 85 ÷ 265 V AC (47÷440Hz) or 85 ÷ 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 > 2 MΩ
Displayed value’s range Risol 5 kΩ ÷ 900 kΩ
Measurement accuracy 5 kΩ … 10 kΩ 2 kΩ
Measurement accuracy 10 kΩ … 900 kΩ ± 10%
Critical insulation resistence Rcrit adjustable 5 kΩ ÷ 300 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 Vef / 3750 Vef
Communication line: RS485 type MASTER-SLAVE, 9600 Bd, even count parity / Insulating strength to the internal circuits and to the network circuits Yes 2500/ Vef
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 conditions
Operating temperature ϑ -10°C ÷ +60°C
Relative humidity 28 g H2O /kg suchého vzduchu
Atmospheric pressure 86 ÷ 106 kPa
Operating position any
External magnetic and electric field max. 400A/m
Overvoltage category / testing voltage III, according to IEC 60664-1:2007
Pollution degree 2, according to IEC 60664-1:2007
Operational mode permanent
Article number 70 911Q
2D model (728.74 KB) for registered only
3D model (469.2 KB) for registered only