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.

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)

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.

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. 👍🏼👍🏼

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

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.

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!

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

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).

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 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.

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

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 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.

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.

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.

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.

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

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

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.

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.

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.

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.

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

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

Notice all the fires are Anet A8? Hmm.

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

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

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!

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 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.

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

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.

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.

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.

Great information and advice Thomas!

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

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

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!

One of your best videos so far

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

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)

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.

Great tips and advice, greatly appreciated!

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

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

Great video. Thanks for putting this together

Thank you for this video Thomas, I was already planning to use those automatic fire suppression cans in metal enclosed case with some simple power shut-off sensor but all the electronic parts informations are excellent for electronically inept people like myself (I can make stuff work but doing it by the book is out of my league). Regarding safety I have few questions that I need to answer before I get into 3D printing. My problem revolves around extremely limited working and living space and health and safety concerns. I can't dump my yet to be acquired Prusa Mk3 into the garage I don't have and call it a day. My current apartment that fits my needs perfectly well (single big room with kitchen annex and small bathroom) and I can't really relocate either way. With Prusa Mk3 eliminating noise problem as well as all the little quirks that let it be fire&forget solution the last concern I'm having is about fumes. We know at this point they're toxic and keeping a printer in your bedroom is a bad idea hence why I didn't pull the trigger on any printer yet despite following the subject for quite some time already. Taking into account limited living space I'm dealing with I was wondering if some DIY airtight enclosure with fumes extractor consisting of a system where air has to be filtered through some active charcoal and HEPA filters would do the trick or whether can you recommend some ready, reasonably priced solutions to address my problem. While some people would ask why I just don't open the window and call it a day I'm just gonna say that where I live it's rather cold thorough the year and given the limited space it would be equivalent of filling my bed with ice cubes which I'm not really thrilled about. I believe I'm not the only one with such a problem and video on the subject would find some target audience if you ever decide to expand on it. Thank you in advance!

Great video Thomas.

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

Very nice video with lots of tips. Thanks!

Thanks for all the great information.

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.

Well this was great reminder! Just checked my printer over and noticed beds connector negative lead having some color chance indicating it has went near combustion temp. Strain relief was earlier on my list of to, but could not figure how to install it since heat bed is one of those aluminum elements, but yeah will be replacing the connector and developing something before next print, since that was way too close to comfort. This is reason why i never print anything while i'm away. I rather cut larger peaces into smaller ones and print them when i have guaranteed time to stay and supervise the thing, or i have someone around to supervise it while i check into store or such, only leaving it alone for going for smoke etc under 5 minutes.

Very well said man! Thanks for releasing this!

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.

nice safety first thank you my guy for your tutorial videos

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

+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.

Well, thank you I guess?... Just checked on my cheap Prusa clone sitting inside of a wooden box. Heatbed cables just fell out of the connectors. One of the RAMPS power cables as well.

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!

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.

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

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.

The 24V power cable for my Ender 3 (Bought Nov 2018) came loose at the PSU mid-print just last week. The increased resistance heated up the wire quite a bit, luckily I was in the room and noticed. Could have easily caught on fire.

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.

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.

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

One could use a thermal camera to identify hot spots in electrical connections, especially at the points where wires/cables flex the most.

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.

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 ?:)

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

Thanks mate for the heads up with the CR-10 and add a 12v auto car fuse to the hot bed

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.

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.

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.

Been waiting for this type of video

I had a connector on my Hictop Prusa i3 3DP-03 catch fire. Burned a hole in the acrylic frame and the MKS base board. Now I use a solid state relay, 24V supply and peripheral, and the better rated MPX.3 board.

I love the automotive fuse idea. Brilliant! Oh yeah and put a battery powered smoke alarm on top of the printer itself. BTW is there a smoke/combustibles alarm that will cut the power automatically? Electrical equipment usually smokes for a while before it combusts so killing the power immediately could save the printer and/or your house.

Hey Thomas, great video. This is a subject i'm somewhat concerned about. I have a Prusa i3 clone that uses a melzi board, which you already know is not a good system, and in my case does not have sturdy enough traces to handle the current for the heated bed. That can be bypassed with a separate mosfet board, but it makes me wonder what else on the melzi board is unsafe. Perhaps you could do a video for beginners on how to swap out melzi boards for RAMPS based systems which are easier to flash and have better components.

Yikes! I had a Monoprice Maker Select V2 that started to melt the heatbed connections. Luckily I caught it and replaced the machine before anything really bad happened. Scary how many companies play it fast and loose with safety.

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

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?

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.

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.

Wouldn't the best engineering solution be to put thermal cut outs in series with the hot end and bed heaters? They're cheap and will work even if the controller has crashed or the mosfets have failed short circuit.

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

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, ...)

Hey Thomas, great vids as usual. There's a lot of newbies out there that dont know how to solder ... and that metal part of the mosfet is live ... pop some links in the video? ...

I was particularly keen on the Sea-Fire FG50A auto-extinguisher, as it uses the FM-200 Halon-replacement and has a pressure switch to cut off the ignition (it's meant for the engine rooms on small boats). I've been emailing various fire system manufacturers for weeks trying to find out if it's possible to get something similar with a mains-rated switch that could cut printer power when triggered. I want to stuff the whole bundle in a steel enclosure as last-resort mitigation. I figure a cheap 12U server rack should do a good job.

Exceptional treatment of this issue!

Hi Tom, I'm big fan of yours, could you make some video about photogrammetry?

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

Grim topic... great video thanks.

I have had my 3D printer catch fire. I was so lucky that I was looking at it as it caught fire, and simply switching the power off was enough to stop the small flame that had started on the stepper motor driver. and I didn't have to use the fire extinguisher i had grabbed after flipping the power switch. what was concerning was the smoke detector inside the room with my 3d printer didn't go off, but the one on my landing did go off.

A tip: a nice encluser is a polycarbonate type. it has a great fire resistance. i have my two printers surrounded by it. Its also a good noise reducer...its an extra.