@gixxerfast said in 230v heatbed thermal runaway:
No fun burning down the house...
A thermal fuse can be another safety measure. Nero3DP has a video on youtube demonstrating how he builds a mains bed with a silicon pad, thermal fuse, and high temp silicon adhesive. On my own printer I have two 115C thermal fuses in series. I also have a mains relay that is connected to the duet's PS ON output such that if the duet thinks something is funny, it turns off power to bed and 24V DC/DC.
Keeping the house intact is very important because it protect the 3D printer from the elements.