483
xkcd #3211: Amperage (imgs.xkcd.com)
submitted 3 months ago by xkcdbot@lemmy.world to c/xkcd@lemmy.world

xkcd #3211: Amperage

Title text:

Oh, and do you have any tips on how to vacuum up copper that's melted into your carpet?

Transcript:

Transcript will show once it’s been added to explainxkcd.com

Source: https://xkcd.com/3211/

explainxkcd for #3211

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[-] nialv7@lemmy.world 82 points 3 months ago* (last edited 3 months ago)

did xkcd just watch the new styropyro video

[-] turboSnail@piefed.europe.pub 23 points 3 months ago

Apparently you saw that 400 battery video too.

[-] Flames5123@sh.itjust.works 11 points 3 months ago

I haven’t had TWO HOURS to dedicate to it just yet.

[-] turboSnail@piefed.europe.pub 1 points 3 months ago

I just put that on in the background while I was cooking, cleaning etc. I actually watched the first 30 minutes like a normal video. During the rest, I was actively looking only about 10% of the time.

[-] Flames5123@sh.itjust.works 2 points 3 months ago

I usually watch these type of videos while WFH but I haven’t been able to these last few weeks.

[-] turboSnail@piefed.europe.pub 1 points 2 months ago

Imagine having those explosions in the background during a meeting 😄

[-] Thteven@lemmy.world 4 points 3 months ago

The slow motion video of the metal turning to vapor was mesmerizing.

[-] turboSnail@piefed.europe.pub 3 points 3 months ago

A still from that video really looks like something from a space telescope. Small glowing dots and a gas cloud in the background.

[-] WanderingThoughts@europe.pub 63 points 3 months ago

"Who did the electrical work in this house?"

"That would be my nephew Thomas, he's very handy."

"When Thomas's house burned down?"

"Oh about two years ago, how did you know."

[-] agentTeiko@piefed.social 50 points 3 months ago

You break ohms law. Its the death penalty for you.

[-] areakode@riskeratspizza.com 3 points 3 months ago

I don't know... What if he's rich and banged some kids? Just boys being boys... /s

[-] palordrolap@fedia.io 47 points 3 months ago

Alt-text should be "Resistance is futile".

[-] BobWehadababyitsaboy@lemmy.zip 3 points 3 months ago

or "fusile"

[-] genuineparts@infosec.pub 40 points 3 months ago

Good old incandescent extension cords

[-] frank@sopuli.xyz 18 points 3 months ago

They're all incandescent if you're not a quitter.

Also everything is a fuse

[-] zurohki@aussie.zone 44 points 3 months ago
[-] marcos@lemmy.world 13 points 3 months ago

Wait, I never noticed!

I can use a fuse with a safe value and still get tasty molten cheese every time I need to replace it?

[-] Zink@programming.dev 6 points 3 months ago

mechanic: So, does it make any noises or can you smell anything burning?

customer: I can't really hear anything, maybe a little hiss or sizzle once in a while. And nothing burning that I can smell. It actually smells really good and I'm getting hungry!

mechanic: aha! I got u fam.

[-] Mcdolan@lemmy.world 5 points 3 months ago

From what I recall 22 rim fire shells are a perfect fit for old car glass fuses.

[-] Bustedknuckles@lemmy.world 22 points 3 months ago* (last edited 3 months ago)

Eh, ~zero impedance house circuits won't do anything bad to normal electronics - it'll just make sure no fires happen in your walls. I do almost all home wiring in 12 gauge and larger for this reason

Actually, the comic only has 500A breakers and don't say anything about wires. Recipe for fire!

[-] Hope@lemmy.world 24 points 3 months ago

I think that's the joke, especially since the alt text asks about getting melted copper off the carpet.

[-] BillyClark@piefed.social 8 points 3 months ago

The comic is talking about the cords that come out of the outlet into the room melting and starting fires. The guy you responded to is talking about wires in the walls starting fires.

[-] Tja@programming.dev 6 points 3 months ago

Ah, the good old asbestos carpets. Cozy!

[-] Cort@lemmy.world 6 points 3 months ago

Yeah, I'm just imagining someone running multiple 0000 gauge (4 ought) cables in parallel to each outlet and switch, and then all back to the breaker box.

[-] WanderingThoughts@europe.pub 6 points 3 months ago

500 amps? That's no wiring, that's cabling.

[-] marcos@lemmy.world 2 points 3 months ago

Dude, the entire comic is about wires.

[-] Agent641@lemmy.world 12 points 3 months ago

Every circuit has a circuit breaker, it's just that sometimes the circuit breaker is the power cord or the product itself

[-] JackFrostNCola@aussie.zone 4 points 3 months ago

'Fuse' would be more accurate.

[-] billwashere@lemmy.world 5 points 3 months ago* (last edited 3 months ago)

18awg at 100A could be considered a fuse. Or a heating element. One of the two.

[-] rumba@lemmy.zip 6 points 3 months ago

First one, then the other.

[-] Bazell@lemmy.zip 10 points 3 months ago

500 amps? Does she have a residential house or a small factory?

[-] marcos@lemmy.world 6 points 3 months ago* (last edited 3 months ago)

My main question is where can I hire a 10000 amps connection?

[-] Bazell@lemmy.zip 6 points 3 months ago

At your local nuclear power plant.

[-] zephiriz@lemmy.ml 8 points 3 months ago
[-] craftrabbit@lemmy.zip 2 points 3 months ago

Just another order of magnitude worse.

Somehow.

[-] brygphilomena@lemmy.dbzer0.com 8 points 3 months ago

If each outlet is its own breaker.. what's he running that's goong to melt those wires?

Unless he has some 16 gauge extension cords going to an electric dryer or something...

[-] CADmonkey@lemmy.world 9 points 3 months ago

Maybe it's styropyro's house?

[-] Nollij@sopuli.xyz 6 points 3 months ago

In the US, most protection comes from the breaker. It's not common (or at least, not standard) to have overcurrent protection on extension cords, power strips, or even the outlet itself. And for typical wiring and uses, it usually works well enough. But it is possible to connect a space heater or hairdryer (1500w and 1800w respectively, due to the 80% rule for continuous draw) to that standard 16-gauge extension cord, or connect multiple space heaters to one circuit. Some homes are wired.... Creatively.... Making it easy to do. In these cases, you're relying on the 15-amp breaker to trip, which would happen quickly. Not quite as quick, but still happens on a 20-amp. But it might melt a 15-amp receptacle first

If it's a 30-amp circuit, it won't trip at all, unless the outlet melts to a short. And this is all assuming the wiring in the wall is rated for that amperage, which is implied but not stated. There are certainly a number of stories where someone upgraded the breaker to keep it from tripping, but didn't upgrade the wiring.

If we assume he's talking about the wiring in the wall, this gets very simple. I once lived in a place where the upstairs bedroom and downstairs living room were on the same circuit. I currently live somewhere where a single circuit controls ALL of the bathroom outlets (multiple bathrooms), the garage, as well as outside outlets. Apparently GFCI outlets were more expensive than the entire mess of running copper all over the place.

[-] bort@sopuli.xyz 5 points 3 months ago

what’s he running that’s goong to melt those wires?

500A on a 110V (220V?) main is a lot of W.

[-] brygphilomena@lemmy.dbzer0.com 2 points 3 months ago

Yea, but what device draws that much power. In the us, most space heaters are 1200w, so about 10 amps. So he'd need to really have a high load device. You might be able to find some 30amp single phase loads.

Putting them all on their own circuit does so much to actually protect him unless he has various extension cords or those 2 receptacle to 6 receptacle devices.

For 500 amps, he should be running 1000 gauge wire. Which would be so impressive to run since each leg would be almost an inch and a half thick and $50 a foot. Each breaker would be over $2k, if he went with the cheapest 500amp breaker.

[-] electric_nan@lemmy.ml 3 points 3 months ago

Electricity is one of those subjects that will forever remain a mystery to me.

[-] fruitycoder@sh.itjust.works 2 points 3 months ago

Reminder the size of breaker in the US electric code is to protect the wire and receptcle. After that you're in someone elses hands.

[-] Greg@discuss.tchncs.de 1 points 3 months ago

Is it a joke about EV charging in Europe? Like there are super duper chargers for super advanced car batteries and rather good coal and nuclear plants but no good network between them?

[-] HK65@sopuli.xyz 5 points 3 months ago

I don't think so, also electric chargers of varying quality are super ubiquitous in Europe.

My little Eastern European hometown of 20k people has two stations of 8 plugs each.

[-] Greg@discuss.tchncs.de 1 points 3 months ago

I agree with your point, but I also assume it’s a not a supercharger-grade? Like in China they have quite often supercharger-grade in cities practically everywhere and prices per kilowatt are no different from slow-charging (like 22kW). While in Europe I noticed that price for kWh is different based on charger’s capacity.

[-] cynar@lemmy.world 4 points 3 months ago

It's less based on the capacity, and more on how much time is likely a premium.

E.g. motorway services are more expensive, since people need the power and want to get back on the road. It's exactly the same logic as the price of petrol there.

[-] Greg@discuss.tchncs.de 1 points 3 months ago

Makes sense! Thank you!

[-] HK65@sopuli.xyz 2 points 3 months ago

One of the two is actually a Tesla supercharger

[-] Greg@discuss.tchncs.de 1 points 3 months ago

Awesome! Thanks!

this post was submitted on 24 Feb 2026
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