The insulation monitoring devices HIG93 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 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 HIG93.
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 MDS-D and MDS-DELTA remote monitoring modules of the monitored power supply system status produced by HAKEL.
HIG93 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.
Two inbuilt signalling relays with switching contacts enables alarm signalling for two independently set values of critical insulation resistance. The insulation monitoring 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 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 or 200 kΩ to 5 MΩ
    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: 2
Supply voltage range Us 90 - 265 V AC or 90 - 370 V DC
Maximum operating voltage of the monitored ungrounded IT power supply system 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 253 V AC / 1A /
3750 Vef /
Signalling relay 2 / Signalling potential-free switching contact / Electric strength to the internal circuits and supply circuits 230 V AC / 1A /
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 mm
Recommended section of the connected conductors S 1 mm2
Operating conditions
Operating temperature ϑ -10°C ~ +60°C
Relative humidity 28 g H2O /kg
Atmospheric pressure 86 - 106 kPa
Operating position any
External magnetic and electric field max. 400A/m
Overvoltage category / testing voltage III according IEC 60664-1:2007
Pollution degree 2 according IEC 60664-1:2007
Operational mode permanent
Article number 70 915
Installation instructions (214.51 KB)
2D model (728.74 KB) for registered only
3D model (469.19 KB) for registered only
Certificates (79.64 KB) for registered only
EC declaration of conformity (83.77 KB) for registered only