A community for a webcomic of romance, sarcasm, math, and language.
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/
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.
Every circuit has a circuit breaker, it's just that sometimes the circuit breaker is the power cord or the product itself
Alt-text should be "Resistance is futile".
"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."
did xkcd just watch the new styropyro video
Apparently you saw that 400 battery video too.
The slow motion video of the metal turning to vapor was mesmerizing.
I haven’t had TWO HOURS to dedicate to it just yet.
Check the resistance. 1,000,000,000.00 Ohms is something to pay attention to.
Good old incandescent extension cords
They're all incandescent if you're not a quitter.
Also everything is a fuse
From what I recall 22 rim fire shells are a perfect fit for old car glass fuses.
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?
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.
You break ohms law. Its the death penalty for you.
I don't know... What if he's rich and banged some kids? Just boys being boys... /s
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...
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.
what’s he running that’s goong to melt those wires?
500A on a 110V (220V?) main is a lot of W.
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.
Maybe it's styropyro's house?
Well for starters most residential outlets are rated for 15 amps. You don't need to run a lot of stuff on that outlet, a vacuum and a space heater is most likely enough for the outlet to overheat. Toss in an extension cord and another appliance and the outlet is going to melt. And since you're only pulling like 25 amps once the short happens when the live parts touch each other the arc explosion would be spectacular. Since you're on a 500 amp switch gear breaker with selective coordination set in a way that not only is the outlet done, but the wiring I'm assuming is not ran to the outlet in 600kcm copper, so all the wiring from the outlet to the breaker is also going up in vapor. By the time the breaker trips your house just went through a neat fireworks show and it's ablaze.
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!
I think that's the joke, especially since the alt text asks about getting melted copper off the carpet.
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.
Ah, the good old asbestos carpets. Cozy!
500 amps? That's no wiring, that's cabling.
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.
Dude, the entire comic is about wires.
500 amps? Does she have a residential house or a small factory?
My main question is where can I hire a 10000 amps connection?
At your local nuclear power plant.
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?
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.
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.
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.
Makes sense! Thank you!
One of the two is actually a Tesla supercharger
Awesome! Thanks!