If they are not connected to a power source, I wouldn't see them as a fire risk. I have over 100 motherboards and an estimated 500+ graphics cards in boxes. Motherboards are on shelves, cards on carpet.

If a capacitor fails while no power source is present, there is no risk other than, potentially, damaging touching components.

I am sure you mean a fire when having old circuits connected to power rather than just storing them (which is safe).

Apart from the "pop" those tantalum capacitors short power to ground when they fail. This can overload power supply if not stopped quickly, especially an old one with less protection and can start a fire under right circumstances. Chances are tiny power lines in electronics devices are destroyed long before they start a fire. So the probability of a fire from that is low. But you never know. As we know a bad o-ring can start a chain of events that can lead to catastrophic failure of a space shuttle when things go really bad...

i meant with no power source connected, no PSU connected .

so i guess its fine to store them without a box, and near a floor that has carpet. there is no risk of a flame starting nor small sparkle

just wanted to know since i started to remove all lithium batteries from old devices like cellphones, videogame consoles, since i discovered after many years of leaving a device stored, that the battery had bulged to triple size and that was a risk of fire, it was great i discovered since if i had kept it where it was, i would be in trouble.

but still if you put a full old desktop computer with the case on the closet where you have clothes. it is still connected to the power supply, and power supplys steel keep a charge when they are turned off and unplugged. would that be bad?

If your devices are not connected to power there is no fire risk whatsoever. Unless you are dealing with laptop batteries, UPS devices or vacuum tubes or other similar devices. Those small caps or batteries present on motherboards/video cards simply don't have enough energy to cause any harm. It is still a good idea to remove batteries as they can leak and destroy circuits.

Some additional info

https://www.niccomp.com/resource/files/alumin … -August2013.pdf

SETBLASTER wrote on 2020-08-24, 20:21:

but still if you put a full old desktop computer with the case on the closet where you have clothes. it is still connected to the power supply, and power supplys steel keep a charge when they are turned off and unplugged. would that be bad?

I think the probability of a fire starting due to the residual charge on the power supply AND propagating due to the clothes in your closet is even lower than being struck by a meteor while walking on the street.

A word of caution about carpet though, is that it can generate static electricity easily, which can damage electronics when discharged (motherboard, peripheral cards etc). So you'll need to take precaution to discharge yourself prior to handling them, or best wearing an ESD wrist strap.

kalohimal wrote on 2020-08-25, 03:24:

A word of caution about carpet though, is that it can generate static electricity easily, which can damage electronics when discharged (motherboard, peripheral cards etc). So you'll need to take precaution to discharge yourself prior to handling them, or best wearing an ESD wrist strap.

Not a wireless one, either. 🤨

There are capacitors which could cause a fire if stored improperly, and even capacitors which need to be stored shorted as the very air can charge them up to lethal voltages. Ones I've seen might only be 200 uF, but that's 200 uF at 200kV.

Short of wandering into a substation rectifier though, you'll never see them. And even then it's unlikely.

As has been mentioned here previously though, Li-ion batteries on the other hand... reddit.com/r/spicypillows/

Vaudane wrote on 2020-08-25, 13:23:

capacitors which need to be stored shorted as the very air can charge them up to lethal voltages.

Got any reading material on this?

Doornkaat wrote on 2020-08-25, 13:39:

Vaudane wrote on 2020-08-25, 13:23:

capacitors which need to be stored shorted as the very air can charge them up to lethal voltages.

Got any reading material on this?

https://eepower.com/capacitor-guide/applicati … energy-storage/

It's not something I can find much interesting reading on with my quick google, it's more taught as HSE for high-energy physics labs.

Edit: here's another one http://www.idc-online.com/technical_reference … _And_Safety.pdf

Vaudane wrote on 2020-08-25, 13:49:

https://eepower.com/capacitor-guide/applicati … energy-storage/ […]
Show full quote

Doornkaat wrote on 2020-08-25, 13:39:

Vaudane wrote on 2020-08-25, 13:23:

capacitors which need to be stored shorted as the very air can charge them up to lethal voltages.

Got any reading material on this?

https://eepower.com/capacitor-guide/applicati … energy-storage/

It's not something I can find much interesting reading on with my quick google, it's more taught as HSE for high-energy physics labs.

Edit: here's another one http://www.idc-online.com/technical_reference … _And_Safety.pdf

Thanks! Do you know wether those reach their full capacity or just a fraction?

Doornkaat wrote on 2020-08-25, 13:57:

Thanks! Do you know wether those reach their full capacity or just a fraction?

Depends on the application. If they're used as energy storage, then they'll be charged up to a decent percentage of their max rated voltage. Like in a Cockcroft-Walton stack (basically a high voltage ac-dc converter) or a Marx bank, they'd be charged up to pretty much full. Because what happens then is they're charged in parallel, then discharged in series. The more voltage you can get into each cap, the higher the total voltage will be when discharged.

For high voltage smoothing and filtering though, they'll be used below their rated capacity, because it stops any saturation effects kicking in. And last thing you want is a HV cap going pop. You're gonna have a bad time in that case. Especially if there are multiple HV caps in the circuit (they'll probably get overloaded due to voltage dump and explode too.)

Vaudane wrote on 2020-08-25, 14:10:

Doornkaat wrote on 2020-08-25, 13:57:

Thanks! Do you know wether those reach their full capacity or just a fraction?

Depends on the application. If they're used as energy storage, then they'll be charged up to a decent percentage of their max rated voltage. Like in a Cockcroft-Walton stack (basically a high voltage ac-dc converter) or a Marx bank, they'd be charged up to pretty much full. Because what happens then is they're charged in parallel, then discharged in series. The more voltage you can get into each cap, the higher the total voltage will be when discharged.

For high voltage smoothing and filtering though, they'll be used below their rated capacity, because it stops any saturation effects kicking in. And last thing you want is a HV cap going pop. You're gonna have a bad time in that case. Especially if there are multiple HV caps in the circuit (they'll probably get overloaded due to voltage dump and explode too.)

Sorry, I guess I didn't word that very well. I mean do they reach a full charge from static electricity or just a partial one.