MakerBot Print is our newest print-prepration software, which supports native CAD files and STL assemblies,
allows you to interact with all your printers via the Cloud, and many other exciting new features.
I'll pitch in.
Both of my first two Ender 3's (my first entry into 3d printing) both caught fire via the xt600 connectors. I was extremely lucky to be home both times. This was last August and September. My printers sit right on my workstation. I was gaming when I smelled the first signs of trouble, looked over just in time to see a small flame erupt from behind the printer. I was quick enough to shut power off, fast enough that I didn't need to use a fire extinguisher (only the plug itself ignited, but didn't have the strength to spread).
My second Ender 3 came 3 weeks after that one, and within a week I experienced the exact same issue, but caught it before it actually produced a visible flame.
Both printers were replaced, and when I received them, both xt60 connectors were removed and new ones soldered on. I then set up a slightly different system as OP. I have my fire alarms connected to an emergency kill switch. If one, or both, go off all power is cut to the area the printers are in. My computer and octopi's are connected to a UPS. If power loss is detected, my computer will send an email and then goes through an automated shut down.
There was a great deal of concern right around this time about these connectors on the Ender 3's, enough that MULTIPLE prominent youtubers made safety videos, and warnings galore went out on the Ender 3 facebook groups. Though I seem to have been the only one to report actually seeing flames.
Those two stories get told a lot because those are the extreme cases of what could happen. The more you can get printers to take head of those possible failures, the more they can be avoided. I've come to learn there, through the VAST community of 3d printers, that there are many small incidents that could have lead to much worse end results. But because of incidents like those big two, most people have precautions in place.
Those few famous incidents should always be kept in circulation. hehe a good reminder that our printers can be dangerous, even if the risk is small.