Thanks to mass production and increasing popularity, 3D printers are now much more affordable and an exciting addition to many hobbyist workbenches. Unfortunately, we are now hearing reports of 3D printers catching fire, destroying the printer entirely, causing damage to homes, and sometimes hospitalizing people suffering from ABS smoke inhalation!

Whilst it is certainly a very rare occurrence, there is an inherent fire risk with any device that heats up to the temperatures involved with 3D printing i.e. over 200°C+. Improper wiring, poor connections, a poor quality power supply, loose heater cartridge or dislodged thermistor could cause a fire. Some early 3D printer models may not include fire prevention measures in their firmware, such as thermal runaway protection should the thermistor move out of position. Be sure you have the latest firmware for your printer.

Considering the number of moving parts and the heat some of them reach, you should regularly inspect and maintain your printer. Check for any loose components, inspect all wiring, tighten any terminals and look for any heat affected components. For added peace of mind, you could build this smoke detector, designed to cut the power to the printer if smoke is detected.

for more information and how to build goto Diyode
https://diyodemag.com/projects/fire_prevention