Is there a device made to send a signal to the hub when 120 AC is present? I want to place a small module in a wall box behind some older light switches to directly sense “light on” and power up additional z-wave lighting.
I’m not sure about a Zwave one beside aeotec home energy monitor (quite expensive), but there are cheap WiFi based alternatives like Shelly EM, if you want an external clamp.
One route you can follow is to add a Zwave relay with energy monitoring and not use the switch part. This will work. Anyone is ok.
depending on wiring a z-wave relay or shelly 1 could be fitted to relay switch status, no need to connect a lamp.
Enerwave ZWN-RSM1 can send unsolicited status reports to the primary controller (Node ID 0x1)
when the switch is toggled if the controller is designed as a gateway
Is this the feature you are referring to??