3211: Amperage

Amperage

|< < Prev #3211 (February 23, 2026)

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

|< < Prev Random Explanation

Explanation

This is one of 68 incomplete explanations: This page was created by a 1.2 MEGAWATT SIMILE. Don't remove this notice too soon please. If you can fix this issue, edit the page!

Cueball explains to Ponytail how he has modified some parts of his house's wiring to avoid having power to his appliances interrupted on account of overcurrent conditions from running too many appliances at once. In many places around the world there is a main breaker limiting the maximum current available to properties, with common limits being 60A, 100A or 200A. Individual circuits will then have breakers limiting the maximum current, usually to something between 10 and 32 amperes. 15-20A is a common breaker size for circuits powering outlets in the US; 32A is the common breaker size in the UK; and 10-16A is standard in mainland Europe. However, Cueball is somehow managing to draw 10,000 amps from his power company, and has also updated his breaker board to allow his wall sockets to draw 500 amps of power. Both numbers are absurdly high — far more than any consumer appliance could need, and, as Cueball soon admits, enough power to cause fire hazards. This is also emphasized in the title text, which shows that Cueball has actually tried out his new arrangement and it has melted the copper inside the cables and outlets onto the carpet, and he is now looking for ways to clean it up.

Cueball's reasoning for this is equally absurd: he is frustrated by his circuit breakers. Circuit breakers exist to prevent more current than is expected from flowing through wires. A tripped breaker is caused by either a short circuit down the line or by the user trying to draw too much power at once. A tripped circuit breaker is an easy fix, but it means whatever you were trying to power on that circuit has been interrupted, which is apparently too much for Cueball. Also, simply resetting the breaker may leave the underlying problem unaddressed, resulting in the breaker repeatedly tripping. Preventing a circuit breaker from tripping, either by soldering wire into the fusebox in place of the fuses or (in Cueball's case) by placing breakers rated at excessively high amperages, defeats this safety mechanism, meaning a fault such as a short circuit is much more likely to become a house fire. The end result is that Cueball has designed an extremely dangerous system with a high level of overkill in order to enable more of his own mistakes and prevent minor nuisances from slowing him down.

Additionally, while Cueball has stated he has changed the service he receives from the local utility company and the ratings of his breakers, he has not stated he has changed the wiring in his house to the outlets. Typical wires for outlets in the US are between 14 and 10 AWG, rated between 15 and 30 amps. In the UK it would likely be a Twin Core and Earth 2.5mm² cable rated for 32A. By drawing anywhere near 500 amps, he will, as he has discovered, most likely melt the wires both inside his walls and inside his appliances and start a fire, even if there is no fault. (Pure copper melts at 1085 °C (1984.32 °F), and the copper in electrical wiring is fairly pure, so Cueball has demonstrably produced temperatures in excess of that. Such temperatures are well above what's necessary to ignite common household items.) Rather than treat this as a sign that his plan was ill-conceived and simply put up with normal levels of power, though, Cueball is now trying to find more durable cords and wires that can handle the excessive load.

The amount of electrical power you can use in your house depends on both the voltage and the maximum current you're allowed to draw. The latter is usually protected and limited by multiple breakers both in your home and at the local substation. For example, in the US, where the nominal voltage is 120V, a 15A breaker would get you a maximum of 1800 watts of power (current multiplied by the voltage). In countries where 230V is more common, a similarly sized breaker would get you a maximum of around 3500 watts. If you decrease the voltage you can still get the same power by increasing the current drawn. For example, to get 3500 watts in the US on 120V, you would need to draw around 30A - double the original amount. Higher currents induce higher resistance in lines, meaning they would need a larger wire to safely draw the power without them overheating and catching fire. Transmission lines solve the problem by transforming the power to a higher voltage (a 400kV (400,000 volts) line transmitting a maximum of 10 amps can still theoretically give out 4 million watts of power without needing excessively thick cables). Conversely, decreasing the voltage means that you need more current drawn for the same amount of power (for example, to get 3500 watts from a 12V car battery you need to draw almost 300 amperes, something that would need really thick wires not to overheat). Assuming Cueball lives in the US with 120V mains voltage, his 10,000A will draw 1.2 megawatts of power, equivalent to the usage of a factory or other large facility.

The comic might be a reference to a recent video posted by youtuber styropyro, who connects 400 car batteries and does various experiments, including popping a 6,000 amp fuse. While the voltage on car batteries is only 12V (or 24V in some cases), they allow drawing very high amounts of current to provide enough power for the starter engine to turn. Drawing 500 amps and more for a short period of time is not uncommon. While these would only amount to around 6kW of power (12V * 500A), the higher current requires the cabling to be thick enough to not overheat even in the short amount of time this draw is used (until the starter engine has turned on the main engine — on a modern car in warm weather this should be around a second at most). In the video, styropyro is connecting 400 of these, which would allow both a higher voltage (when connecting them in series) and a higher current draw (when connecting them in parallel), which he uses to get the desired setup for his experiments. He uses not just very thick cables but also large pieces of thick metal as well to make sure the setup itself doesn't break because of the high currents involved.

Transcript

This is one of 47 incomplete transcripts: Don't remove this notice too soon. If you can fix this issue, edit the page!

[Cueball and Ponytail are standing near the corner of a room, with Type B outlets on either wall surrounding the corner at about knee height. Cueball has raised one hand slightly to gesture to one of the outlets.]

Cueball: I got 10,000 amp service and put each outlet on its own 500 amp breaker, so I never have to worry about overloading a circuit again!

Ponytail: Clever.

Cueball: Oh, that reminds me- do you know where to buy cords that don't catch fire?

  Add comment        Create topic (use sparingly)       Refresh 

Discussion

Seems like this would be at least tangentially related to the Cursed Connectors series, although it's just the outlets and cords this time. Zakator (talk) 05:51, 24 February 2026 (UTC)

I would assume that this is related to styropyro's latest video? 142.126.42.193 05:59, 24 February 2026 (UTC)

I’ll second the comment about the new styropyro video; it seems very likely that it inspired Randall to make this comic and is probably worth a mention. 2607:FB91:829C:47BD:C826:B8DB:5A5E:913A 07:50, 24 February 2026 (UTC)

I think that's very likely - in literally every single group of nerds (eg xkcd-adjacent) I've seen people talking about it. I'd be very, very surprised if he hasn't at all seen itR128 (talk) 17:28, 24 February 2026 (UTC)

200 amps is NOT "an amount of electricity power"; The amp is a unit of electrical current, from which power can be derived by multiplying by voltage.2001:8003:7087:E602:3CBE:B25:5BFC:61BD 07:41, 24 February 2026 (UTC)

The current explanation seems to assume that Cueball is aware in advance of some of the problems his scheme is likely to cause, and is trying to forestall them. That seems unlikely - it's Cueball after all. It's far more likely that he has already melted all his wiring (and ruined his carpet), but just considers that a new engineering challenge to overcome. 82.13.184.33 09:28, 24 February 2026 (UTC)

It is amusing or instructional to consider how residential wiring would be engineered if the equipment and circuits were designed with a system that supplied constant current rather than constant voltage. Long ago carbon-arc streetlights were all wired in series and run at perhaps 6 or 8 amps. The "failure" mode is not a short circuit but an open circuit. Protective devices close the offending open. Perhaps Cueball would like to explore such a system, running megavolts at 500 amps, unless he already has. 173.188.198.217 12:56, 24 February 2026 (UTC)

I understand the theory of it, and it clearly doesn't cause any more electrical fires than home run circuits, but the UK's 32A ring circuits on 14 gauge wire will always make me raise an eyebrow. 64.135.140.145 13:36, 24 February 2026 (UTC)

xkcd is a good distractor from everything that's going on with the world. Thanks, Randall! --DollarStoreBa'al^Converse (BLM) 13:57, 24 February 2026 (UTC)

Retired electrical engineer from a power distribution manufacturer here... The resistance in the wires doesn't increase all that much with increasing current. The increase in heat generated is proportional to the amount of current flowing through the wires. Double the current and the heat generated doubles. Go from 15 amps to 500 amps and the heat generated by the resistance in the wires increases about 33 times. 2600:1702:7A0:8230:9DBF:A415:F8AF:7799 17:10, 24 February 2026 (UTC)

Isn't heat generated proportional to current squared? or is that resistance. maybe im trippingR128 (talk) 17:28, 24 February 2026 (UTC)

Power lost as heat is determined by voltage drop in the line times current [P=IV] and since voltage drop equals current times resistance [V=IR] then heat is determined by resistance times current-squared [P=I*(IR)], so half current makes one quarter of the heat.57.140.28.40 18:19, 24 February 2026 (UTC)

120V AC at 15A would not be 1800W. 120V DC would, but the AC power is a sine wave, so to get the overall average power you need to divide by the square root of two. 2600:1009:B1AC:BBBB:1D51:D689:1D5F:6A11 17:50, 24 February 2026 (UTC)

To commenter above: 120V in the US is RMS voltage, so it's already divided.

To original poster: "and inside his appliances and start a fire, even if there is no fault" Unless the appliance itself is drawing more than it's rated for (e.g. 15 or 20A (unlikely)) there's no reason the appliance's internal wiring would disintegrate because it's on a 500A circuit.

I'm assuming the "cords" cueball refers to are extension cords (which are themselves overloaded) vs. appliance cords which shouldn't have any problem unless the appliance was already suffering some kind of short.

74.76.64.197
        Add comment