I’ve just watched an old tv show where the main character is tortured in someone’s basement with a live wire. The current is obviously flowing from the wire, through him and into the ground. Why does this not cause the fuse to blow?
I think this is probably just an error on their part, but I’m kinda curious now if that’s actually correct or not. I’m tempted to steal the idea for a book I’m writing but I’d need to know first whether or not that’s a valid method of torturing someone (never thought I’d find myself writing that sentence 😆).
In: 5
Why do you think that would cause a fuse to blow?
Fuses blow when you try to run more *current* through them than they are rated. Generally somewhere around 10 amps or so.
Current equals Voltage/Resistance. This means that if you have a really high voltage, but also a really high resistance the current is low. So if you have a million volts going thru 1 million ohms of resistance your fuses will be fine.
Infact, most torture via electricity will be a lot less than 10 amps. Electrica chairs (you know…used to *kill people*) usually never go past about 12 amps or so.
This is of course ignoring the very easy (but dangerous) option of just…bypassing fuses.
A fuse or circuit breaker (at least, typical ones) only measure flow of electricity in one direction. You just add them onto any one wire, typically the one that isn’t the “neutral” wire, and now you have protection. They just measure current/amps through that wire, and cut it off if it goes above the limit.
That said, unless you’re wet, the human body doesn’t conduct much electricity. At household voltages, electricity going through your body over your heart will likely cause your heart to stop beating, and muscles to contract, but that’s still fractions of an amp. Most fuses/circuit breakers are rated for a couple of amps… 15+ is common if you’re talking about your home’s power distribution panel.
At 15+ amps going through their body, a human would be cooked alive. Like, cooking any other kind of meat in an oven. I don’t want to think what it would do to your nervous system. I should expect you’d be dead real quick, or at least very screwed up. Not effective for *torture* if you’re, like, trying to get a person to give up secret information, if you’re just gonna destroy their body as quickly as the outlet will allow.
If your goal is to use electricity to torture someone, you could always just bypass the fuse.
People used to do this (unsafely) all the time when fuses were actually the standard instead of breakers. If the fuse blew, and you didn’t have spares, you would turn off a few things and then shove a coin in to complete the circuit until you could get a new fuse.
An RCD would blow – this is a device that measures the difference in electricity on the live and neutral wires. If there’s a difference then it means some electricity is flowing to ground and the RCD trips. Many countries mandate these on household wiring. However they are easy to bypass if you had malicious intent. These are designed to trip at a very small imbalance and are very important for safety.
A fuse however only blows if the current is above a high level (often for a sustained period of time too). The human body isn’t that conductive (not compared to a copper wire anyway), and the current wouldn’t be high enough in most situations. The body’s resistance is orders of 100’s of ohms – so the current would be fractions of an Amp. Most fuses require 10’s of Amps to blow.
Haha that’s a good question.
Fuses present too much current from going through – think of it like pressure build up. Now if you’re not connected to ground, it is very possible that this will trigger your fuse because the pressure will continue to build up.
However, if you’re the path to ground in an easy manner, then the circuit might not draw enough power to trip the fuse. Electricians thought about this when designing GFCIs (Ground Fault Circuit Interrupters) – those are the special outlets that you see in your kitchen and bathroom. Thy work by looking for a mismatch between incoming and outcoming current.
If you’re going straight to ground, the incoming current is not equal to the outcoming because some of it is going to ground; and the circuit trips and cuts power! This also happens with water.
So in short, it’s possible if they’re connected to ground that they wouldn’t trip the breaker – but only if the outlet isn’t a GFCI one!
Fuses are designed to protect the house wiring from overheating in the walls and causing a fire. The average fuse is usually something like 16 or 32 amperes. That is significantly more than what a human body can conduct without specifically trying to maximize current with things like stabbing the conductors through the skin. However you can be in great pain from as low as 0.0001A and 0.01A or more starts being dangerous to your life, so there is several orders of magnitude room for some jumper cable fun before the breakers step in.
A modern domestic electrical setup in a country with proper safety standards (I exclude the USA from that) would have RCDs which would trip. Historically just fuses were used which wouldn’t necessarily. After all your body has resistance and so limits the current to some finite value.
No, it is very unlikely it would blow a fuse/circuit breaker. The human body has too much electrical resistance, so not enough current will flow to blow the fuse.
Fuses and circuit breakers are there to protect the wiring from overheating. They aren’t intended to protect people from being electrocuted. But in newer homes (since maybe the 1980’s) you are likely to find GFCI devices (ground-fault circuit interrupter — the name in the USA). These are intended to protect people from electrocution. These would trip and prevent the torture situation. GFCI devices are most often seen in the bathroom, kitchen, and outside outlets. But they can be anywhere. I believe there are some that can protect the entire house.
Fuses blow and breakers trip when you have more current flowing through them than what they are rated for. The amount of current needed to electrocute someone is far less than the amount needed to run a hair dryer or a microwave, so electrocution alone will probably not draw enough current to blow a fuse.
However, as others have mentioned, there are a few different ways to tell if something is wrong while still being under that threshold. An easy way to tell if something is wrong is a device that can detect live/ground differential, which will sense when current flows through the wrong path, which can trip a breaker but will not blow a fuse. But there is no guarantee anything other than a fuse has been installed, and in most homes that’s all you have.
20 amps will kill the *shit* out of you. That is a common breaker limit in US households. It doesn’t actually take that much electrical energy to kill somebody, much less hurt them. A regular battery can sometimes do it, if it’s run through the proper device.
A regular battery caps out at something like 2 watts. A taser battery might be closer to 100 watts. Car batteries clock in at upwards of 1,000 watts. A hefty vacuum cleaner draws 2,000 watts straight from the outlet and doesn’t blow a fuse.
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