We're trying to create an action for when an outlet starts drawing power (someone turns on a household appliance in a non smart switched way), but we can only seem to create an action when someone turns on an appliance through toggling a smart switch either through their phone or the switch's physical button.

Specifically, we want to control a bathroom exhaust fan so that it turns on with the bathroom light and remains on for n minutes after users turn off the light. Rewiring bathroom switches is highly impractical and bathroom users cannot be expected to use any smart switch located elsewhere.

How can we do this?