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| Amperage |
 Title text: Oh, and do you have any tips on how to vacuum up copper that's melted into your carpet? |
Explanation
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. The usual (and much safer) approach is to increase the number of power lines in the house, each with its own breaker, to distribute the possible load, and to not connect too many items to each. If one found that a breaker was being tripped, one would rearrange the devices' connections to the outlets to find a better power distribution.
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 °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 voltage drops as a function of resistance in lines, which causes heat to generate as the square of current [P=IV, V=IR, therefore P=I*(IR)=(I^2)R], 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 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, though note that this is a reasonable current draw from a car battery). 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 connects 400 of these into 80 parallel 65V cells, reaching peak currents in excess of 100kA. 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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