I don’t have any kind of HA at the moment, but I’ve done some temperature/humidity/contact/light sensing and data collection projects.

Are there any commercial or DIY ways to report when a device is running without messing with the wiring? My current idea is an accelerometer to be triggered by vibration, but if there’s an electrical solution that doesn’t involve leaving a clamp attached, I’d be interested.

This is specifically different than using a smart plug to monitor, because something like HVAC is hard wired.