6 ms·

I'm a little worried that if these get made to the same standard that most usb cables are that one of these is going to kill someone.

dogma1138 12y ago
That's 20V over 5amps that won't kill anything... Lenovo and some other companies already charge their laptops via USB (Normal A Type connector) on a dedicated port that connects to a 65W power adapter...
- matmann2001 12y ago
  20V over 5A could definitely kill someone.
  - rasz_pl 12y ago
    in order to pump 5A with only 20A you would first need to liquefy someones flesh
    - ars 12y ago
      You should stop posting false information. A simple wound is enough. 5A @ 20V is 4 ohm. A wound is lower than that. And you don't need 20A to kill anyway. 20V with sweaty salty skin is right at the edge of dangerous territory.
      - rasz_pl 12y ago
        go ahead and stab yourself with a multimeter, your gonna read somewhere around 300-1000ohms
        DanBC 12y ago
        http://darwinawards.com/darwin/darwin1999-50.html http://darwinawards.com/darwin/darwin1999-50.html > (1999) A US Navy safety publication describes injuries incurred while doing don't's. One page described the fate of a sailor playing with a multimeter in an unauthorized manner. He was curious about the resistance level of the human body. He had a Simpson 260 multimeter, a small unit powered by a 9-volt battery. That may not seem powerful enough to be dangerous… but it can be deadly in the wrong hands. > The sailor took a probe in each hand to measure his bodily resistance from thumb to thumb. But the probes had sharp tips, and in his excitement he pressed his thumbs hard enough against the probes to break the skin. Once the salty conducting fluid known as blood was available, the current from the multimeter travelled right across the sailor's heart, disrupting the electrical regulation of his heartbeat. He died before he could record his Ohms. "It's the volts that jolt but the mills that kill" - voltage gives you the electric shock feeling but current across the heart will kill you.
        zyx321 12y ago
        It's a Darwin Award because you have to go out of your way to achieve it. When was the last time you plugged in a USB device while bleeding profusely from both hands and/or standing barefoot in a pool of your own blood? Unless you are actively, visibly bleeding, it's going take well over 50V to cause any sort of lasting harm. Not to mention that it'll almost certainly default to 5V unless both ends are plugged in to devices supporting higher voltage.
        DanBC 12y ago
        He was not bleeding profusely from both hands nor standing in a pool of blood. He stuck the probes into his thumbs. This sub thread is not so much about whether it is probable that a person will die but whether it is possible that a person could die. And, with some convolutions, you can work out a situation where a person could indeed die. Importantly rasz_pl is claiming that 50 mA cannot kill you. The rule of thumb is 50 mA at 50 V across the heart is enough to kill you. This voltage level is dropped if the skin is broken - and you don't need a big wound. If you're saying it's fantastically unlikely to actually happen: I agree.
        rasz_pl 12y ago
        so many clueless people downvoting :/ >50 mA at 50 V across the heart is enough to kill you. 1 Voltage doesnt matter! 2 AC 60hz, not DC. I dont know the state of safety education in US, but in Europe it was the first thing on the first day of EE lab. Quick google: "The threshold for ventricular fibrillation for direct current shocks longer than 2 seconds is 150 mA as compared with 50 mA for 60-Hz shocks; for shocks shorter than 0.2 seconds, the threshold is the same as that for 60-HZ shocks, that is, approximately 500 mA" so >2 seconds at 45 volts if you jam two live wires at 45V into your open wounds across the heart and here are some funny, but educational yt clips https://www.youtube.com/watch?v=hp97GjuULX8 https://www.youtube.com/watch?v=hp97GjuULX8 https://www.youtube.com/watch?v=XDf2nhfxVzg https://www.youtube.com/watch?v=XDf2nhfxVzg
        DanBC 12y ago
- ars 12y ago
  You can actually kill with 20V - just stab the copper wire into the thumb of each hand. 20V is fine through skin - too much resistance, but if you push it under the skin the resistance is much lower and it can kill. You might be able to do it with sweaty skin and squeeze the wire hard. Not certain. Not likely to happen by accident though. Also it's enough to cause a burn if you put it in your mouth.
  - rasz_pl 12y ago
    no you cant, thats gonna be ~60mA of DC across your body provided you have open flesh wounds on both hands :) painful yes, but not deadly
    - CamperBob2 12y ago
      60 mA is a big deal, as it's getting into the current levels that are more likely to cause fibrillation (at least for AC). But the only way 20V will push that much current through your body is through open wounds. In a worst case scenario, yes, 20V could electrocute a person. More likely, though, a crappy USB cable carrying 5A will kill people by burning their house down.
      - e12e 12y ago
        Some interesting points on "low" voltage and wounds here. I wonder about child proofing (and, as you say, fireproofing!). Will most people regard these as "100 watt dangerous" or "peripheral/signal-cable safe"? Frankly, I'm worried enough about the possibility of fire due to power over ethernet (eg: hotel wifi). All that said, modern, useful, standardised dc cabling does sound convenient.
    - okasaki 12y ago
      http://www.mpoweruk.com/shock.htm http://www.mpoweruk.com/shock.htm 20-50 mA - Can't breathe. Paralysis of the chest muscles. Possibly Fatal
      - rasz_pl 12y ago
mieses 12y ago
They are very safe. Toyota uses them for cabling around compressed hydrogen fuel tanks.
- desdiv 12y ago
  That's very cool. Do you happen to have a picture of it?
  - mieses 12y ago
    It will be featured it the advertising photos. Frayed USB cables sparking next to compressed hydrogen. It will work a little like the subliminal death messages in the Marlborro cigarette ads, which were also very cool.
- ars 12y ago
  That doesn't mean it's safe for a person. For hydrogen you want to avoid sparks, for a person you want to avoid current (which is delivered by having enough voltage).

dogma1138 12y ago

That's 20V over 5amps that won't kill anything... Lenovo and some other companies already charge their laptops via USB (Normal A Type connector) on a dedicated port that connects to a 65W power adapter...

matmann2001 12y ago
20V over 5A could definitely kill someone.
- rasz_pl 12y ago
  in order to pump 5A with only 20A you would first need to liquefy someones flesh
  - ars 12y ago
    You should stop posting false information. A simple wound is enough. 5A @ 20V is 4 ohm. A wound is lower than that. And you don't need 20A to kill anyway. 20V with sweaty salty skin is right at the edge of dangerous territory.
    - rasz_pl 12y ago
      go ahead and stab yourself with a multimeter, your gonna read somewhere around 300-1000ohms
      - DanBC 12y ago
        http://darwinawards.com/darwin/darwin1999-50.html http://darwinawards.com/darwin/darwin1999-50.html > (1999) A US Navy safety publication describes injuries incurred while doing don't's. One page described the fate of a sailor playing with a multimeter in an unauthorized manner. He was curious about the resistance level of the human body. He had a Simpson 260 multimeter, a small unit powered by a 9-volt battery. That may not seem powerful enough to be dangerous… but it can be deadly in the wrong hands. > The sailor took a probe in each hand to measure his bodily resistance from thumb to thumb. But the probes had sharp tips, and in his excitement he pressed his thumbs hard enough against the probes to break the skin. Once the salty conducting fluid known as blood was available, the current from the multimeter travelled right across the sailor's heart, disrupting the electrical regulation of his heartbeat. He died before he could record his Ohms. "It's the volts that jolt but the mills that kill" - voltage gives you the electric shock feeling but current across the heart will kill you.
        zyx321 12y ago
        It's a Darwin Award because you have to go out of your way to achieve it. When was the last time you plugged in a USB device while bleeding profusely from both hands and/or standing barefoot in a pool of your own blood? Unless you are actively, visibly bleeding, it's going take well over 50V to cause any sort of lasting harm. Not to mention that it'll almost certainly default to 5V unless both ends are plugged in to devices supporting higher voltage.
        DanBC 12y ago
        He was not bleeding profusely from both hands nor standing in a pool of blood. He stuck the probes into his thumbs. This sub thread is not so much about whether it is probable that a person will die but whether it is possible that a person could die. And, with some convolutions, you can work out a situation where a person could indeed die. Importantly rasz_pl is claiming that 50 mA cannot kill you. The rule of thumb is 50 mA at 50 V across the heart is enough to kill you. This voltage level is dropped if the skin is broken - and you don't need a big wound. If you're saying it's fantastically unlikely to actually happen: I agree.
        rasz_pl 12y ago
        so many clueless people downvoting :/ >50 mA at 50 V across the heart is enough to kill you. 1 Voltage doesnt matter! 2 AC 60hz, not DC. I dont know the state of safety education in US, but in Europe it was the first thing on the first day of EE lab. Quick google: "The threshold for ventricular fibrillation for direct current shocks longer than 2 seconds is 150 mA as compared with 50 mA for 60-Hz shocks; for shocks shorter than 0.2 seconds, the threshold is the same as that for 60-HZ shocks, that is, approximately 500 mA" so >2 seconds at 45 volts if you jam two live wires at 45V into your open wounds across the heart and here are some funny, but educational yt clips https://www.youtube.com/watch?v=hp97GjuULX8 https://www.youtube.com/watch?v=hp97GjuULX8 https://www.youtube.com/watch?v=XDf2nhfxVzg https://www.youtube.com/watch?v=XDf2nhfxVzg
        DanBC 12y ago
ars 12y ago
You can actually kill with 20V - just stab the copper wire into the thumb of each hand. 20V is fine through skin - too much resistance, but if you push it under the skin the resistance is much lower and it can kill. You might be able to do it with sweaty skin and squeeze the wire hard. Not certain. Not likely to happen by accident though. Also it's enough to cause a burn if you put it in your mouth.
- rasz_pl 12y ago
  no you cant, thats gonna be ~60mA of DC across your body provided you have open flesh wounds on both hands :) painful yes, but not deadly
  - CamperBob2 12y ago
    60 mA is a big deal, as it's getting into the current levels that are more likely to cause fibrillation (at least for AC). But the only way 20V will push that much current through your body is through open wounds. In a worst case scenario, yes, 20V could electrocute a person. More likely, though, a crappy USB cable carrying 5A will kill people by burning their house down.
    - e12e 12y ago
      Some interesting points on "low" voltage and wounds here. I wonder about child proofing (and, as you say, fireproofing!). Will most people regard these as "100 watt dangerous" or "peripheral/signal-cable safe"? Frankly, I'm worried enough about the possibility of fire due to power over ethernet (eg: hotel wifi). All that said, modern, useful, standardised dc cabling does sound convenient.
  - okasaki 12y ago
    http://www.mpoweruk.com/shock.htm http://www.mpoweruk.com/shock.htm 20-50 mA - Can't breathe. Paralysis of the chest muscles. Possibly Fatal
    - rasz_pl 12y ago

mieses 12y ago

They are very safe. Toyota uses them for cabling around compressed hydrogen fuel tanks.

desdiv 12y ago
That's very cool. Do you happen to have a picture of it?
- mieses 12y ago
  It will be featured it the advertising photos. Frayed USB cables sparking next to compressed hydrogen. It will work a little like the subliminal death messages in the Marlborro cigarette ads, which were also very cool.
ars 12y ago
That doesn't mean it's safe for a person. For hydrogen you want to avoid sparks, for a person you want to avoid current (which is delivered by having enough voltage).