When wiring a ButterflyMX video intercom directly to an electric lock, there is an inductive voltage kickback. Inductive kickback occurs when the current across an inductor is interrupted, resulting in an electromagnetic interference that can cause component damage to our video intercom. This kickback requires you to install a diode near its DC-powered lock and a resistor near its AC lock. Read this post to learn how to protect the video intercom from inductive voltage kickback.

To protect your video intercom against inductive voltage kickback, you will need:

  • Isolation relay with a separate power supply (we recommend Altronix RB5)
  • Diode for DC-powered locks or a resistor for AC-powered locks


Tools needed for inductive kickback voltage


As described in our installation documentation, directly controlling an electric lock with a ButterflyMX video intercom requires proper electrical isolation. To protect the ButterflyMX video intercom from inductive kickback from the electric door lock, installers need to introduce an isolation relay with a separate power supply.


Inductive kickback


Be sure to read the rest of our instructions on how to install ButterflyMX.


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Meredith Murray

My passion lies at the intersection of real estate & technology. Brooklynite always.