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ABB Low Voltage

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ABB Low Voltage Controls

The CM-IVN serves to extend the measuring range of the insulation monitoring relay CM-IWN.x for monitoring the insulation resistance up to 690 V AC and 1000 V DC in accordance with IEC 61557-8. The CM-IVN is available with two different terminal versions. You can choose between the proven screw connection technology (double-chamber cage connection terminals) and the completely tool-free Easy Connect Technology (push-in terminals).

ABB CM-IVN Insulation Monitoring Relays for Unearthed Supply Systems Distributors

CM-IVN Range

The coupling unit CM-IVN is designed to extend the nominal voltage range of the insulation monitoring relay CM-IWN.x up to 690 V AC and 1000 V DC. The coupling unit can be connected to the system to be monitored by means of the terminals VL+ and VL-. The terminal V⏚ has to be connected to the earth potential. The terminals L+, V1+, L-, V1-, VS and VE have to be connected to the CM-IWN.x as shown in the connection diagrams below.

Supply systems with voltages Un = 0-690 V AC (15-400 Hz) or 0-1000 V DC can be connected.

If you are looking for ABB CM-IVN Coupling Units, please call us on (844) 331-9372 or email us at we will do our best to help you find the ABB measuring relays that you are looking for at competitive prices. If you are searching for ABB monitoring relay technical information (data-sheets) please use the datasheets or product selection guide page links.


  • Expansion of the nominal voltage range of the insulation monitoring relay CM-IWN.x for monitoring the insulation resistance of unearthed IT systems up to 690 V AC and 1000 V DC
  • According to IEC/EN 61557-8 "Electrical safety in low voltage distribution systems up to 1000 V a.c. and 1500 V d.c. - Equipment for testing, measuring or monitoring of protective measures - Part 8: Insulation monitoring devices for IT systems"
  • Passive device, no supply voltage needed
  • Screw connection technology or Easy Connect Technology available
  • Housing material for highest fire protection classification UL 94 V-0
  • Tool-free mounting on DIN rail as well as demounting
  • 45 mm (1.77 in) width

With CM-IWN.x a pulsating measuring signal is fed into the system to be monitored and the insulation resistance calculated.

This pulsating measuring signal alters its form depending on the insulation resistance and system leakage capacitance. From this altered form the change in the insulation resistance is forecast.

When the forecast insulation resistance corresponds to the insulation resistance calculated in the next measurement cycle and is smaller than the set threshold value, the output relays are activated or deactivated, depending on the device configuration. This measuring principle is also suitable for the detection of symmetrical insulation faults.

Always connect L+ and L- to different conductors. L+ and L- can be connected to any of the conductors.

Our industrial factory automation supplies distributors warehouse in Boise, Idaho stocks some ABB Products enabling us to further assist you in finding the correct CM-IVN relay for your application in the USA, Canada and Mexico. Whether we have insulation monitors in stock in Boise, Idaho or need to get them from ABB; Clearwater Tech can get CM-IVN coupling unit to you fast and save money! It will be very helpful if you have the CM-IVN relays part numbers ready, then our sales representatives can provide you with a pricing and availability quote for insulation monitor that you are looking for in seconds. If you do not have the part numbers for ABB CM-IVN coupling units, our application engineers will be able to help you figure out the part numbers and get the price quote to you as soon as possible.

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