As a firefighter myself this is a good topic to be covered. With things being made cheaply to keep cost down safety is the part of the trade off. It's always a good idea to do routine inspections of your equipment to make sure there's no problems before it becomes one.

This was actually one of my biggest concerns when I designed my 3D printer. Here is a list of all the things I did to prevent fires. - Lots of fuses. My bed and my hotend have there own fuse. The board also has its own fuse - All heaters currents go around the board, not through the board. The bed has an SSR - All Marlin safety features used - When SSR's fail, they stay open all the time. Therefore I use a relay which can shut off the current going to the bed and the hotend. The relay is operated by the firmware and is turned on when the printer turns on, and turned of when the kill procedure is activated. - There is a mechanical bimetal switch on the bed which switches the bed of at a curtain temperature in case of a firmware error with the bed heater. - My printer prints inside an enclosed frame. I have a smoke detector inside the printer frame. Smoke will be detected at a very early phase. My printer actually failed once because the connector switching the safety relay got lose. It is always funny when your ridiculous amount of safety features cause problems of there own.

My printer is a Ender 3 v2 Neo, and I’m kinda glad you talked mostly about kits because that’s less stuff I need to worry about I guess

I've been thinking about picking up some "Stove Top Fire Stop" fire extinguishers for my 3D printer enclosure. I made an All-wood enclosure (even though you discount it, having an all-plastic enclosure is just as bad, maybe worse) for my printer. There are a number of automatic fire extinguishers that rely on a fire melting something to release the retardant. I think this is something we need to see in the 3D printing community.

Thanks for making this, you have really helped a lot of people.

Gypsum board/drywall... there's a REASON it is used in structures. So instead of making a wooden box, build a drywall box with the wood frame OUTSIDE the panel; any flames that occur can only come in contact with drywall. (Note drywall will not contain a raging fire, and the "seams" are a weak point but you can use angle bracket framing to help prevent any flames from leaking out)

Awesome Video Tom!!! I own an Anet A2 I have two small children at home, and the first thing I did was upgrade the main wiring for the heated bed and from the power supply with 12awg silicone wires, also bought spade connectors, auxiliary mosfets, a 33amp power supply, smoke alarm, changed the connectors on the heated bed, and managed the wires properly... now I just bought inline fuses for both the hotbed, and hotend!! Thank you for this, one more thing that I can add to my printer for some more peace of mind!

I would like to see a series on this where you review a few board components and which connectors are in which printers. Many of us do not open that cover to even know which board (connectors) we have and which type of MOSFET or even if we have fuses. If we don't have fuses, which two wires on our board do we fuse, etc. and thank you very much for taking the time and care to post us this informative video as a start. 👍🏼👍🏼

Finally a new how-to informational-tutorial like video! This is the content I subscribed to. More like this please!

Really great video! Something you might have added, when talking about improving your printers safety are external mosfets: They are designed with more current in mind, so they will have reserves, but they also come with connectors that are capable of dealing with higer current than the stock connectors on the control board. And by using an external mosfet you lower the current going to your contol board, lowering the danger of using the bad connectors for power supply of the control board. And it will allow you to add a fuse just for the mainboard with a rather low value, because all the big currents will run on the external mosfets. I think it is a major safety upgrade for a 3d printer to use external mosfets for hotend and heatbed and use 3 fuses - one for the headbed, one for the hotend and one for the controlboard (without heatbed and hotend current).

I had the cheap ramps connector melt on me once. I ended up buying a bag of 12v barrel jack connectors for it instead and just pressed it in the pins. Works like a charm and it hasn't melted or shown any signs. Good stuff.

My machine is in an IT rack that ended up being just the right size for it and its accessories, it's extremely cheap second hand, it's sturdy metal with a glass window and has plenty of mounting points for cameras, raspberry pi, spool holders and whatnot, it keeps the ambient temperature predictable and avoids drafts, keeps everything dust free and it looks badass. ^^

The only time I've had a thermal runaway is when my layer cooling fan shroud was poorly designed and cooled the nozzle. Also, if fire is a huge concern, there's likely a way to wire up a fire alarm to main power of the printer.

Fantastic safety video! Wish I knew this stuff when I was building my first printer

I run 34 printers in wooden enclosed shelves right now. Just bought some of those stove top fire suppression devices. Going to put them in a couple to make sure there are no false positives and then put them with every printer. Going to be about $1000 but will absolutely be worth it.

Great wealth of Info Tom, Thanks for putting this out ! Happy Extruding !

One of your best videos so far

I also own an Anet A8, for roughly a month now. Today has been a very weird day for my relationship with it. I received the recommended mosfets and a soldering iron in the mail, got really stoked about how well it's lasted and started taking it down. When I took the bed connector off, it wiggled right out of place and had a nice scorch mark on the side next to the 12v pin. After following the community's suggestions of "fixing it", I see Thomas has released a video with even BETTER suggestions about this very issue! I can't recommend enough that if you buy one, get the electronics and do some soldering... I really don't think these are complete right out of the box. That being said, it works quite well. I've binged hours of different 3dp content before and during my ownership, and i'm really happy with the quality of what little I have made. I would still recommend it to people, with the stipulation that you treat it like it needs to be treated. Like a cheap piece of miniature chinese industrial equipment. lol.

Great video Thomas. I will definitely go over all my printers now and fireproof them even more. Keep up the good work.

There is a company in the UK called Jacktone who sell "Auto fire extinguishers" the just have a hose connected to the valve. When the hose ruptures from heat, the extinguisher releases its content. These are great and work without triggers, cable or other moving parts which have been known to fail and not trigger the fire extinguisher​.

I'm 3D printing in an old house, in a closet in an office that's off of another room, none of which have fire alarms. So, something was telling me to be careful... I'm glad my intuition kicked in. Definitely will not run my printer overnight

I love this video. Ive been advocating so many of these safety tips for so long. A few more things I may suggest: Cork pads/mats. Cork dosen't burn like a yoga mat or rubber mat can. Makes for a great insulator for a printer to sit on to help limit sound vibrations, Can be easily gotten and used to help insulate mountings of electronics from metal frames. Sheetrock. Another good, non-flamable material you can set your printer on top of to help keep a table top from spreading a fire, this is the same reason it is used on the interior walls of a house or gun safe. Another idea I have seen people do with RC batteries that may work for a 3D printer if there is a large enough rack over head of it, A large plastic bag full of sand. The basic theory is the heat from a fire melts the bag, dumps the sand and smothers the fire. The sand also can help to limit spread of any melted plastic to help stop the spread of anything burning. KNOW WHERE YOUR GAS LINES RUN IN YOUR HOME!!!! Dont print next to gaslines. Should a printer fail, it being near an even bigger fuel source can make the situation worse. Yes, gaslines are rated to deal with some degree of flame to help stop failure, but dont blindly trust it on its own. Just a few ideas for v2 of fire safety video :P

Thank you greatly for this information, it has certainly changed my mind about which 3D printer to purchase.

If you’re printing in a basement or garage that has exposed ceiling with pipes, it’s pretty cheap to have a plumber add a fire sprinkler. Several years ago I had a plumber add a couple around our gas hot water heater and gas furnace and that cost about $150. I run my printer on the other side of my furnace a few feet away but still under the sprinkler and have no fear.

this is a really talked about topic, loved the video. keep it comming

How great! I have learned so much from watching you. You pointed out a fault on the Creality CR-10. I bought one. They must have watched your video because they thought they solved that with a plastic strain relief attachment. The only problem is, it prevents the bed from leveling because they attach it under the bed the a leveling lug. I sent mine back, after making a video pointing it out. Personally, after taking mine apart, I would never own a Creality. They are assembled poorly. It printed 1/10 of the Cat before shutting down with Thermal Runaway. I took the heater block apart and they had bent the thermistor wires right at the base of the bulb, breaking it; not to mention tightening it too much and squishing the insulation. I replaced it with a Winice M09, slightly smaller, but I love double Z screws, not to mention assisted bed leveling.

I plan on using a smart smoke detector. I'm almost finished with my enclosure. One of my other hobbies is automation. I personally use Smartthings to control lights and doors. I already have a power switch that my 3d printer runs through. I can power off and on the printer remotely if needed. It comes in handy when that one print is almost done but I have to go to work. With the smoke detector in the enclosure, I plan on setting it up to automatically turn the printer off if it detects smoke. That way, if the smoke is electrical in nature, it should prevent a fire if is detects it early enough. I would expect it to also work for catastrophic print failure that balls up on the nozzle and causes any smoke.

Absolutely great videos. my personal favorite to watch out of other peoples!

Fantastic video and highly valuable information, thanks a ton for making this video!

Great information and advice Thomas!

Very good video! You should always use wire end caps/ferules/cable shoes which are properly crimped. They also prevent single strands of the wire to stick out or shorting with neighboring cables.

great video thomas as usual. full of good info. :)

I have an Anet A8, which is notorious for being dangerous. It's pretty much stock, but I did double check everything during assembly and took my time to do the wiring as well as the design and my equipment allowed me. It's been printing really well for almost 6 months now, but I will do some temperature checking with an IR camera this week, just to be sure.

Excellent advice! Gonna follow all of it Real Soon Now...

Great video. Thanks for putting this together

You just cost me $1,000. After seeing the FireStop I like the idea so much I bought 32 of them to go over my printers (1:1). Thanks Tom! Great info!

Great video Thomas.

Great tips and advice, greatly appreciated!

Thanks for all the great information.

Very nice video with lots of tips. Thanks!

Been waiting for this type of video

I didn't know about those auto fire extinguishers, so thanks for that.

Awesome video, I'm always paranoid about electrical fires. Another safety measure would be to (if you can) have your 3d printer on a fire retardent surface. I do this with my lithium ion cells whenever I leave them unattended just in case.

This video should be pinned at the top of ALL Anet facebook and reddit groups! Thomas PLEASE keep up the amazing work. Every video I think you have hit peak quality levels in video and audio but nope you keep improving and I don't understand how. I know quality will plateau at some point but now its a question of when.

Super Video, wie immer 😎. Danke für die Hinweise und Anregungen. Greetings from munich, Tom.

Didn’t know you do shout outs to patreons :) Nice to hear myself named there (3D Passion) :) Your content Tom is top notch. Every your research is so deep and awesome, I am amazed every time. What an awesome job you are doing on educating lots of people about 3D printing and how to do it right! Keep it up! And hey, I may see you here in USA in may in California :) I will be on that fair too! Would love to meet Joel as well!

Thanks for the tip about tinned wires. I did that while adding a MOSFET board to mine, going to go and fix that now!

This was a great Video, far better than your "overclock your Powersupply and set your house on fire" Video !

Great video, I installed a power relay with thermal fuses on my printer that shuts down all power if anything gets warmer than I want it to.

11:30 you can also use an old tape measure to add support to wires. It works well with braided wrap. Not sure about spiral wrap.

Good point on mentioning not to put 3D printer inside wooden create. I have seen lots of printer put inside plywood crates to create heat enclosure since it’s easy to make. If you can make another video on how to make proper fire safe enclosure , that would be really awesome!

These are good tips. I really need to install the strain relief on my original CR-10 (my CR-10S came with it). I haven't had any emergencies yet and do a lot of multi-day prints...but I always worry a little bit!

I read a lot of comments that the A8 is "Always the one to set itself on fire. " I know this isn't true. But part of the problem is that the Anet A8 is a home build printer. So the quality of hiw it is put together can have a huge bearing on how safe it is to use. The tips in the video are all valid and I would also add that a 3D printer should be 'serviced' at regular times. Chect the wires for problems. Check nuts and screws are tight etc. Lightly oil the rods etc. But yes. Treat these items with care and respect.

I learned a lot from this, thanks. Especially about the wire relief on the bed. I didn't know about the strands breaking down over time with movement. Had to solder new wires to my A8 bed as they used insanely thin wire which you would use for LED lights on the back of a TV, not for heating up a bed to 110C! I thought those printed chain cable management designs were just glorified cable tidies. Didn't realize they were for strain relief.

Very well said man! Thanks for releasing this!

This Should be a mandatory video for anybody who opens a package with a 3d printer. Kit or ready assembled.

Notice all the fires are Anet A8? Hmm.

nice safety first thank you my guy for your tutorial videos

Great video!

Great video. Please do a video comparing CNC routers or anything about them and give us all you know I’m sure many people would like it. Thanks you’re the best.

Strange I saw the notification for this video on my phone but can't seem to find it on your yt channel on my desktop on a fresh tab even after cleaning my cache an everything

2:52 i just looked over to my very own wooden-box-with-styrofoam-insulation-printer Situation and giggled a little

Excellent video topic👍

What filaments do you store in dryboxes, or dry before printing, and what filaments do you just print without worrying about moisture?

Some great tips here!

Clear and concise, like all your videos. I have a doubt, my printer lost the connection to the raspberry a few days ago, it never happened before, but I could see that the heaters remained on. Is there any configuration in Marlin that turns off the heaters when it does not receive commands for a certain time? Thank you.

The one key thing is regular maintenance - monthly, quarterly, whatever fits your bill. Check loose connectors, measure circuit resistance and voltage drop (for oxidation), tighten all screws, visually check the PCB for delaminated pads, etc. The vast majority of failures and accidents are caused by neglect, in any engineering discipline. Regarding thermal runaway protection - if your board triggers it and you don't want to disable it completely, look for THERMAL_PROTECTION_PERIOD / THERMAL_PROTECTION_HYSTERESIS / WATCH_TEMP_*. It's still a hack for a faulty hardware, but better than nothing.

Great video... I’m wondering what board would you recommend most. In stuck between an Ensiy, DuetWifi and Cohesion3D unless Tom would be willing to design a board for the community

Grim topic... great video thanks.

Exceptional treatment of this issue!

The thermal runaway doesn't stop that instance of a slow wiggle out of a heater cartridge. It lit up because it was supplying the right temp to the thermistor, but when it fell out it was super hot, lighting up the fan shroud. Thermal runaway will cut the power once it falls out after the timer expires, but until it cools, you still have a super hot cartridge touching flammable plastic.

Also worth mentioning: Power mosfets turning into shorts (probably due to ESD damage), had this happen to me twice on a "ancient" RepRapPro Huxley (Melzi controller). Both times i happened during the heating phase for the hotend where I remove any ooze with a pair of tweezers (metal ones) No fires as I was next to it, but the first time around I spend too long considering my options, resulting in having to "rebuild" the hotend. After the second time I have switched to an e3d v6 clone hot end, hope its heater cartridge insulation might be better than then wirewound resistor in the older original hotend design. Anyway as the hotend (and steppers) now runs off 12V I'm considering switching to an ATX PSU to allow Marlin to switch off the power if it detects a problem.

Thanks for the video Tom, very helpful. I would like to know what your take is on the value of the primary fuse ( integrated in the power socket) of the CR-10? Mine is rated at 10 amps which I am thinking is a bit too high for a 220V circuit?

Tom, your smoke detector is mounted wrong. There should be at least 50cm space to a corner, wall or lamp. The smoke does NOT reach your detector. Placing the detector on the ceiling is allways better. Most detectors aren't even rated for wall mounting. Many electrical shop's are certified by the TÜV, you should ask them to mount your smoke detector. If you want to do it yourselfe check out the DIN 14676. Please fix it. Right now your smoke detector is just a piece of plastic without any use. Would be nice if you can make an update to show the propper mounting.

hello, is an ikea lack enclosure can be good like it will not take fire easily

It would be pretty cool if the smoke alarm was connected to the power of your printer so that when it goes off, it shuts off the printer. (kinda like a Ground fault power outlet, but smoke alarm tripped)

Thanks for the video,

I just invested in nine smoke alarms that interconnect so when one goes off they signal each other and all go off. Great since I have three sheds and a garage that if one went off during the night when we were asleep we would still notice in time to possibly do something about it. Decided to get them as a mate had a fire when he left his laser cutter alone in a shed (two weeks ago) whilst he went to peel some potatoes. I also invested in some fire extinguishers as well. Was about £250 altogether but worth it in the long run.

Creality seems to have paid attention to the forums and emails from customers because my CR-10 arrived with the heat bed strain relief already installed and the heat bed was insulated as well. I suspect that Creality will eventually honor the GPL license agreement since they are listening to their customers.

I got excited when I saw the CR-10, thinking Tom would be fire-proofing it in the video. Then I'd just use the video as a guide to do the exact same things, step by step, to my CR-10. But I'll just suck it up and do it without that extra help. Still very useful video, thank you.

love the idea of installing a kitchen fire extinguisher above the 3d printer.

Thanks very good video everyone with a 3D printer should watch. At 5:18 those connectors melted on my first printer and almost caused fire. I removed them and soldered decent gauge wires directly.

Holy crap, did not know any of this. I'm getting my first filament printer, a Prusa I3 MK3S, which I feel more confident doesn't use cheap components and is engineered better, but still getting connected fire alarms and automatic fire extinguisher.

I have an acustic fire alarm mounted on top of the printer (and a second one on the ceiling of the room). Another simple and cheap idea to stop the fire from spreading in the first place is to put a large ceramic tile under the printer. And keep a minimum distance between the printer and anything flammable (curtain, desk, paper etc.) of at least 1m.

Thomas- just finished building a plywood enclosure for a printer. I have one of those "range hood fire suppressant" devices in it, and I think I will also paint the inside of the enclosure with high-temp paint (often used in a BBQ or to paint a car engine). Anyhow, sounds like we're on the same track.

Today was a8 safety day - direct soldered the heatbed/motherboard. Thanks for the reminder.

Love this video. Would love a video where a cheap kit like an a8 ist completely reworked to be safer ( fuses, midget, wires, cable management, fw, ...)

As for Marlin safety features, if you're having issues, rather than disabling them, you can slightly relax, how strict they are. If I remember correctly, there's a time period, and heat offset. If the heat reading stays off from target for longer than given period of time, the print will be stopped, and all heaters shut down. So basically you can increase the allowed difference, or increase time period, or both.

Do you think you can do a review on the Duet WiFi controller ?:)

Is it better to have one single fuse on the psu OR, a fuse tapped in-line with the heatbed and an other one for the hotend?

Out of the box what issues need addressing for the Prusa i3 MK3?

Did you write an article on this because the phrases in both are almost identical and the pics of the 3d printers are the same as those that feature in the vid

I've got a CR-10 on the way. I'm no EE by any means. I do have a STL ready to go to print a relief cradle for the bed wiring, but what other steps should I take to make sure that the CR-10 is safe enough to run overnight or unattended for an hour or more? Does the CR-10 have issues with runaway heating?

The wiring behind the power switch on my printer started smoking. I'm glad I was standing right there when it happened.

Tinning wires also creates a rigid point of stress for the wire isn't allowed to flex, and eventually individual wire strands will break. I suggest using crimped ferrules.

Why would anyone down vote this video. This is great info that anyone should listen to.

Do you think a fire extinguisher ball such as the "AFO Fire Ball" or "Elide Fire Ball" as available on Amazon are worthwhile protection?

thanks for advise !

Just a quick one. Octopi with Temperature Failsafe and Smartplug plugins Plus a smoke alarm hacked onto an Arduino and a 433mhz remote. That way, if there is smoke then the smoke alarm and Arduino will shut off the power via 433mhz and if the temperatures start going out of bounds then the Pi will shut off the smart plug. Did that on my Tevo Tornado a couple of years back. Would also suggest a GFI device. Did a vid on it all showing setup too.

+Thomas Sanladerer That smoke detector is in a BAD spot you should have it in the centre of the ceiling - putting it on a corner like that means the airflow could keep smoke from going through the detector. I'm a former firealarm technician and I have seen smoke alarms fail in locations like that.