I'd like to measure voltage and current for a mains circuit using a microcontroller, and connect this to ethernet. Since I want to have 8 independent outputs, using an isolation transformer to measure the current for each port quickly becomes expensive. So I thought of just using shunt resistors to measure both voltage and current. This is not a problem for the microcontroller, but it is when interfacing with the external world.
Then I remembered that Ethernet already has isolation. Specifications say ethernet connections are coupled with isolation transformers rated for 1500V .
I was wondering if this isolation is safe enough for a mains circuit? If so, I could build my circuit completely non-isolated and rely on the ethernet transformer for isolation. The device won't have any other means to interface with people (maybe just LEDs, but no buttons or knobs)