3211: Amperage

Amperage

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

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Explanation

This is one of 69 incomplete explanations: This page was created by a SMOKE ALARM POWERED 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, a main breaker limits the maximum current available to each property, with common limits for single-unit residences being 60 A, 100 A or 200 A. Individual circuits will then have breakers limiting the maximum current, usually to something between 10 and 50 amperes (the higher end is reserved for electricity-intensive appliances like dryers, vehicle charging stations, or air conditioning systems). 15-20 A is a common breaker size for circuits powering regular outlets in the US, 32 A is common in the UK, while 10-16 A is standard in mainland Europe. However, Cueball has convinced his power company to supply up to 10,000 amps. This scale of service is more appropriate for large apartment towers with 100 or more apartments, major offices, and industrial facilities, and generally requires the building to run its own transformer to convert from medium voltage to low (one transformer would normally be shared by up to dozens of single-unit residences). Such a power plan and the infrastructure to manage it would be prohibitively expensive and comically overkill for most individual homeowners.

The purpose this massive upgrade was to allow a similarly oversized electrical panel, with a 500-ampere circuit breaker for each wall socket. Multiple outlets in one room or several nearby rooms usually share a circuit, so this would have required running separate wires to each outlet, and this internal wiring would have had to be much thicker to carry such high currents without overheating and starting a fire (since the house is still standing, Cueball presumably found an electrician willing to do this). North American electrical codes require that the current over a long period be lower (such as 80% of the nominal rating), so 500-amp wires would allow a sustained load of 400 amps under the code.

Both numbers are absurdly high — far more than any consumer appliance could need. This also appears to be where Cueball abandoned the electrical code, as the special wiring has been connected to what appear to be standard 15- or 20-amp US outlets. Cueball admits that regular wires catch fire when used with these outlets, because even if the outlets are tough enough to carry hundreds of amps, regular consumer power cords are not. The title text shows that Cueball has actually tried out his new arrangement and it has melted the copper inside the power cords 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 currents from exceeding a level that would damage the wires or equipment along the path. A tripped breaker is caused by either a short circuit (unlikely here since this could produce currents well over 500 amps) or by the user trying to draw too much power at once (such as by plugging in many large appliances in one room or even into one outlet using power stripes). A tripped circuit breaker caused by coincidental overloads can be reset easily, but constant overloads would require other solutions. Preventing a circuit breaker from tripping, such as by soldering wire into the fusebox in place of the fuses or installing breakers with limits higher than the physical rating of the wires, defeats this safety mechanism, making fires more likely. The usual safe approach to overload issues is to move some devices to different outlets that are on separate circuits. If needed, one can increase the number of circuits in the house, each with its own breaker (as Cureball has done), but it is still important to match the outlet types to the circuit capacities and follow manufacturer's instructions about equipment power limits. Cueball's expensive approach has kept the internal wiring safe while allowing dangerous habits beyond the outlets, such as using power strips to supply multiple large loads from one outlet.

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 2.5 mm² cable rated for 32 A. By drawing anywhere near 500 amps, he will, as he has discovered, most likely melt the wires inside his appliances and start a fire, even if there is no fault. (Pure copper melts at 1085 °C (1984 °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 per outlet, though, Cueball is now trying to find more durable cords and wires that can handle the excessive load. If he upgrades all remaining power cords to sizes sufficient for the electricity that they carry, the system might become technically safe. However, electrical inspectors would still flag the mismatched outlets, and any modified power cords would likely fail various other safety standards enforced by governments or insurance companies.

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 120 V, a 15 A breaker would get you a maximum of 1800 watts of power (current multiplied by the voltage). In countries where 230 V 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 120 V, you would need to draw around 30A - double the original amount. Higher currents induce higher voltage drops as a function of resistance in lines, which causes heat to generate as the square of current [V=IR; P=IV; therefore P=I×(IR)=I²R], meaning they would need a larger wire to reduce the resistance in the line and allow more surface for heat to dissipate in order 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 400 kV (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 12 V car battery you need to draw almost 300 amperes, something that would need really thick wires not to overheat, though note that this is a reasonable current draw from a car battery). Assuming Cueball lives in the US with 120 V mains voltage, his 10,000 A 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 12 V (or 24 V 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 * 500 A), 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 connects 400 of these into 80 parallel 65 V cells, reaching peak currents in excess of 160 kA. His setup requires very thick cables and large pieces of solid metal to handle the extremely high current.

Transcript

[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?

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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)

The US's pathetically wimpy system always raises an eyebrow for me. No wonder Cueball felt the need to upgrade his house. I would also be frustrated by not being able to run a kettle and a toaster on the same circuit simultaneously. No tea and no toast?? Sacrilege! Martin (talk) 22:21, 24 February 2026 (UTC)

>"frustrated by not being able to run a kettle and a toaster on the same circuit simultaneously." Why must it be the same circuit? The US NEC code calls for TWO 20A circuits in kitchen/pantry. US market kettles are, in your opinion, underpowered, 1500 Watts (or less!), so as to run comfortably on even legacy 15A circuits. The toaster goes on the other kitchen circuit. --PRR (talk) 00:52, 25 February 2026 (UTC)

Wow, two circuits are mandated?! That goes to show how dire the situation is with their limited available power. Martin (talk) 05:52, 25 February 2026 (UTC)

Just use the stove for your Tea and Toast 66.210.7.66 16:01, 25 February 2026 (UTC)

Just microwave the lot and be done with it. 176.138.186.7 21:31, 25 February 2026 (UTC)

2.5mm2 is actually more closer to a 13 gauge (which corresponds to 2.6mm2), and with it being in a ring so electricity has two ways to go it's more closer to what a 12 gauge (3.3mm2) would be able to hold. Sztupy (talk) 22:48, 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 squared. Double the current and the heat generated quadruples. Go from 15 amps to 500 amps and the heat generated by the resistance in the wires increases about 1100 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

Absolutely correct. Appliances are designed with appropriate internal wiring, so if the appliance is drawing 500A the appliance can handle 500A. The cord from outlet to appliance is the issue here, as Cueball has already mentioned. Martin (talk) 22:21, 24 February 2026 (UTC)

Could this perhaps be a reference to 3198: Double-Pronged Extension Cord? Logalex8369 (talk) 21:06, 24 February 2026 (UTC)

There is nothing in the comic to suggest the internal wall wiring is melting or catching fire. I think we can assume Cueball has upgraded the internal wall wiring to match the breaker upgrades. Cueball is only enquiring about cords which don't catch fire, and "cords" are the external extension leads. Cueball doesn't say anything about internal wall issues. Martin (talk) 22:30, 24 February 2026 (UTC)

TL;DR this is a setup that would make Tim Taylor (from the sitcom Home Improvement) jealous. 2603:6011:853A:4DDA:3F9A:6297:AF9E:2340 04:43, 25 February 2026 (UTC)

I think 1000 MCM copper wire would be sufficient for the cords: https://www.cerrowire.com/products/resources/tables-calculators/ampacity-charts/ https://nassaunationalcable.com/products/1000-mcm-thhn-thwn-2-stranded-copper-building-wire 2600:6C54:4E00:99C:67B7:D578:30ED:2471 04:42, 25 February 2026 (UTC)

Yet another example of the absolutely heinous overexplanation problem on modern exkcd. A comic whose joke boils down to "guy gets rid of electrical safety equipment and is surprised by the creation of serious electrical hazards as a result of this" has exploded to nearly 1400 words across 7 gigantic paragraphs with long extraneous tangents, in just two DAYS after the comic went up. This entire comic could be explained in 4 sentences for the main joke and an extra sentence for the title text. Pie Guy (talk) 04:58, 26 February 2026 (UTC)
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