3D Printer Fire protection

[Jeroen3]

Ehm. A hotend failure is a combined failure of thermistor and firmware, or single failure in control mosfet.
I'm not sure if the fan can keep a 100% heater cool.

If it goes, it literally melts out of the extruder onto whatever is below.

I do not think most of the 3D print materials even know what UL94 means.

[janoc]

Guys (and girls), stop assuming that the only way a fire can start is due to to a thermistor failure! Or that the hot end by itself can't start a fire because it is not hot enough. That's just not the case at all.

E.g. this guy had an Anet A8 (a printer notorious for fires) catch fire, because the heater cartridge (not thermistor!) fell out of the hot end and landed on the plastic on the bed. A thermal runaway detection would have hopefully caught this before too late but this printer doesn't come with it by default.

https://www.thissmarthouse.net/dont-burn-your-house-down-3d-printing-a-cautionary-tale/

More problems with Anet A8:
https://vectormfg.net/anet-a8-firestarter/
https://letsprint3d.net/critical-safety-mods-upgrade-anet-a8/

Anet A8 bed connector overheating, causing fire:
https://dan.bemowski.info/2017/12/09/heat-bed-connector-tips/

Another Anet A8 bed causing a major fire (this guy had Marlin installed, so presumably the thermal runaway protection was present - didn't help):
https://www.thingiverse.com/groups/anet-a8-prusa-i3/forums/general/topic:25274

Here a kid died because hairspray fumes (hairspray is commonly used to help with the plastic adhesion to the bed) were ignited by a spark and caused an explosion, which ignited highly flamable materials nearby (flash paper!):
https://www.telegraph.co.uk/news/2016/11/03/teenage-boy-killed-in-3d-printer-explosion-during-school-art-pro/

Fire most likely caused by a piece of insulation foam from the enclosure detaching and falling on an hot part of the machine (Rostock Max):
https://www.fabbaloo.com/blog/2015/9/30/more-on-the-case-of-the-3d-printer-fire

Monoprice printer almost catching fire due to poorly installed inappropriate connectors:
http://blog.lessdebug.com/2016/12/3d-printer-almost-fire.html

Wanhao i3 actually catching fire due to the same problem (the Monoprice above was a rebranded Wanhao i3), with a dumbass user turning it on again after it started to smoke:
https://www.3dhubs.com/talk/t/wanhao-i3-v2-1-catches-fire/8651

Another Wanhao with the cloned Melzi board:
https://blog.adafruit.com/2017/03/23/the-melzi-problem-or-why-did-my-wanhao-i3-duplicator-catch-on-fire/


And those are only a few examples. Except for the first one, none would have been prevented by the thermal runaway protection.


Printers without the thermal runaway protection with stock firmware (could be out of date):
https://community.octoprint.org/t/octoprint-tells-me-that-my-printers-firmware-lacks-mandatory-safety-features-what-does-this-mean/350

This includes CatalinaWOW's Ender 3 with stock firmware. BTW, that Ender 3 has also those XT60 bed connectors that are a fire hazard:
https://makersteve.com/2019/04/16/safety-first-replace-those-bad-xt60-connectors-ender-3-fix/

Fires don't always start where you expect them to happen.

[Fire Doger]

Never leave unattended device working.
It's not just 3D printers, this includes every device in your house/work. In industrial field they shut off every (non 24/7 like fridge) device from the fusebox switches at closure.

[CatalinaWOW]

I agree.  For maximum safety you should open the mains breaker any time you leave the house.  Even the fridge can cause a fire.

[paulca]

100 points for safety, 1 for practicality.

However what I intend to do is put smart switches on plugs.  The idea is that most rooms will have two "buses".  Essential and non-essential.  I already have this in my office/lab as it has the most things plugged in.  So as I leave I have one switch to press which will turn off all non-essential items at the mains.  Leaving only things like the network switch and server powered.

I'm going to extend this to the living room and the bedroom, which I don't think has an essential bus at all.

Ultimately, by grouping all the non-essential bus switches in the house I can hit a single button on my phone (or the wall at the back door) to switch everything off that can be switched off.

Nothing is every totally safe and life is about risks versus rewards.

EDIT: Actually there will be three buses in some rooms, the "High power bus" is where anything that pulls more than an amp or two goes.  So I don't get into working out if I have an overload on 4 way plugs for example.  Thankfully there aren't many of those and they would be considered non-essential anyway, but harder to smart switch.

[janoc]

100 points for safety, 1 for practicality.

However what I intend to do is put smart switches on plugs. 

And instead of potentially getting a fire from e.g. a TV you will get one from a crappy cheap remote controlled plug that has failed. Never mind the "fun" when some interference will prevent you from turning your lights on (had this happen with a cheap kit like this!).

If you really want to do this for safety reasons (and not just because you want to turn stuff on and off with your phone), have a second set of wiring for the non-essential stuff installed, separately fused and just pop the breaker when leaving. Yes, more expensive than a bunch of $5 "smart switches" and not as fancy as clicking stuff on your phone but actually adding some safety for a change instead of reducing it.

[Monkeh]

If you really want to do this for safety reasons (and not just because you want to turn stuff on and off with your phone), have a second set of wiring for the non-essential stuff installed, separately fused and just pop the breaker when leaving. Yes, more expensive than a bunch of $5 "smart switches" and not as fancy as clicking stuff on your phone but actually adding some safety for a change instead of reducing it.

Breakers are not functional switches. Please do not do this.

[janoc]

If you really want to do this for safety reasons (and not just because you want to turn stuff on and off with your phone), have a second set of wiring for the non-essential stuff installed, separately fused and just pop the breaker when leaving. Yes, more expensive than a bunch of $5 "smart switches" and not as fancy as clicking stuff on your phone but actually adding some safety for a change instead of reducing it.

Breakers are not functional switches. Please do not do this.

OK, install a proper isolation switch. Even that breaker is still better than those cheapo "smart switches"/plugs.

[themadhippy]

Breakers are not functional switches

unless the 18th edition has changed the goal posts again,an mcb is allowed as a functional switch,fuses  and links are not.

[Monkeh]

Breakers are not functional switches

unless the 18th edition has changed the goal posts again,an mcb is allowed as a functional switch,fuses  and links are not.

The good book sayeth:

(5) Circuit-breakers and RCDs are primarily circuit protective devices and, as such, they are not intended for frequent load
switching. Infrequent switching of circuit-breakers on-load is admissible for the purposes of isolation or emergency switching.
For a more frequent duty, the number of operations and load characteristics according to the manufacturer's instructions should
be taken into account or an alternative device from those listed as suitable for functional switching in Table 537.4 should be
employed.

So in general, no, an MCB, RCBO, RCB, or other protective device is not suitable for use as a functional switch by BS7671.

[themadhippy]

presume thats in the 18th edition of the big expensive book of multiple amendments as i remember this coming up on the 17th course   which led to a discussion about the difference between a fuse and an mcb.

[paulca]

Yes, let me just rush out and get spark to rewire my home for £4000 adding a whole new set of 4 plug rings and dozen new plug sockets tracked into the walls. 

I checked for fires, there are some, but either because people are dumb enough to run 16 Amp heater off a 10 Amp plug or because they did dodgy hacks to them, like this guy:
https://community.home-assistant.io/t/warning-burned-sonoff-basic-modified-hacked/84775

Emmm... running wall heaters on them and hacking an inappropriate diode into the main line.  It's also an older model with non reinforced tracks.  Darwin award in my view.  You just can't fix stupid.

Mine are rated to 10A and I do not intend to run anything close to half of that on them.  I'm in the UK so all my plugs are fused so if the device connected to the switch shorts the plug fuse will blow, there will of course also be a fuse in the 4 way power bar or it's plug.  I can go as far as replacing the fuse in the plug with a 5A fuse.  The switch itself has a fuse for it's own power supply and it looked to be up to standard when I took it apart.

I have done a bit of due diligence and it does look like the CE marking on the device is valid and the company is prepared to send the test reports and certificates to you on request.  This would mean that as long as they are not modified my house insurance would still be valid.

[Jan Audio]

Does these things catch fire alot ?, it wont be more risky then charging a LIPO accu, right ?

[bd139]

They don’t catch fire that often. They’re as dangerous as a soldering iron really. Don’t leave it unattended and have a suitable extinguisher available and the risk is low.

The biggest risk was the Anet A8 which has an entirely plastic frame which was flammable and in all cases where it burned people’s houses done it was unattended from what I could see. The Ender 3 has aluminium extrusion parts so fire spread risk is mostly the PLA and electrical failure.

[Jan Audio]

So where do you all place these things ?
What is your safety plan ?
What is your setup.

Mmmm, do not leave unattended, so in my shed no.
On the balconny, yes.
In the kitchen, yes.

I,m gonna read the manual first before ordering.
Look what the manual says : Never use the device to make any electrical appliance.
They are meaning 220volt i think.

[bd139]

Placement: Fire place
Safety plan: Only operates while I'm in, as does all of my equipment. Powder fire extinguisher and blanket available.