Normally when I had some cable melt or GPU blow up a capacitor all it does is make the rig crash. Never led to an actual fire. However I was always worried.

Kept all the rigs on metal open air cases and on a metal rack and kept away from anything flammable. Also had extra smoke detectors near the mining rigs. So if anything happened when I was home I would run quick. If I wasn't home then that's another issue.

I guess you can have a remote smoke detector and some cameras, you see the rig go up in flames you can call the fire dept. No idea if it would help that much since you are remote however.