3 ms·

You didn't mention where you are. In any case, regardless of geographical location, voltage doesn't kill you -- current does. In Australia most household circ

by Jedd 6y ago

You didn't mention where you are. In any case, regardless of geographical location, voltage doesn't kill you -- current does. In Australia most household circuits are ~230V AC at 50Hz at 10 Amp, though 15 Amp circuits are not uncommon (the earth pin - we have three pins in a frowny-face configuration, earth being the lower / vertical one) on those are much larger, so you can't accidentally put that into a standard 10A (female) socket. We have three-phase options too, which is ~ 415V AC - not something that's commonly used in residential environments. In any case, 230V @ 10A is less dangerous than 110V at 15A.

bluGill 6y ago
V=ir. That simple equation is why you are wrong. Double the voltage and the current goes up. The human body is high enough resistance that you won't blow a fuse so current depends on voltage.
- Jedd 6y ago
  I get V=ir, but I'm not seeing any good answers to the question of non-linearity of humans' resistance. I will note that 0.2A is enough to stop your heart, and 2A will almost definitely kill you (with enough damage that you're probably not coming back). Consequently I'm not sure how a 15A (USA) circuit could be considered safe even in the relative sense.
  - kube-system 6y ago
    Voltage determines the current that actually flows during a shock. The amperage ratings you are citing are the maximum amperage that can be drawn before the breaker pops. This protects from fire, it does nothing to prevent death from shocks, in any country. You will be burnt to a crisp before you trip the current-limiting breaker, in any country. High voltages are dangerous because they can overcome the resistance of human skin, which then enables current to flow.
    - Jedd 6y ago
      Right, so assuming everyone's got dry hands, or comparably dry hands, then you'd expect to see lower fatality rates in the USA (and other countries that use ~110V) compared to countries that use 230-240V. Does that hypothesis actually align with the data? I'm struggling to find good figures that spell this out on a region by region basis. The data are often muddied, f.e. by including lightning strikes, ladders or trucks hitting overhead high-voltage power lines, self-harm / suicide attempts, etc. For example, some Australian data for a 2-year period [1] > 55 deaths involving electrical injury - 50 male, 5 female > 8 were lightning strikes > 17 were intentional self-harm > 18 were were due to exposure to other specified electric current Either way that's about 26 / year out of a population of ~25M ~= 1 per million. In the USA I'm finding: > Electrocution is the fifth leading cause of occupational injury death > 41% of cases involved overhead power lines Alternatively [3] for USA: > Electrocution is sixth among causes of workplace deaths > Electrical hazards cause more than 300 deaths 300 out of a population of ~330M ~= 1 per million [1] https://www.aihw.gov.au/reports/injury/electrical-injuries-deaths-hospitalisations-14-16/contents/summary https://www.aihw.gov.au/reports/injury/electrical-injuries-d... [2] https://injuryprevention.bmj.com/content/8/4/306 https://injuryprevention.bmj.com/content/8/4/306 [3] https://www.electrocuted.com/safety/statistics/ https://www.electrocuted.com/safety/statistics/
      - Jedd 6y ago
        Addenda - my numbers are wrong. I was including lightning strikes in the AU numbers, but the US numbers were electrical (lines, domestic, construction, etc) only. So fatality ratios skew higher in the USA than AU, at least. The numbers are quite low in both cases, so the ostensible safety benefits of 110V at 15-20A may not be terribly compelling in practice.

by Jedd 6y ago

bluGill 6y ago

V=ir. That simple equation is why you are wrong. Double the voltage and the current goes up. The human body is high enough resistance that you won't blow a fuse so current depends on voltage.

Jedd 6y ago
I get V=ir, but I'm not seeing any good answers to the question of non-linearity of humans' resistance. I will note that 0.2A is enough to stop your heart, and 2A will almost definitely kill you (with enough damage that you're probably not coming back). Consequently I'm not sure how a 15A (USA) circuit could be considered safe even in the relative sense.
- kube-system 6y ago
  Voltage determines the current that actually flows during a shock. The amperage ratings you are citing are the maximum amperage that can be drawn before the breaker pops. This protects from fire, it does nothing to prevent death from shocks, in any country. You will be burnt to a crisp before you trip the current-limiting breaker, in any country. High voltages are dangerous because they can overcome the resistance of human skin, which then enables current to flow.
  - Jedd 6y ago
    Right, so assuming everyone's got dry hands, or comparably dry hands, then you'd expect to see lower fatality rates in the USA (and other countries that use ~110V) compared to countries that use 230-240V. Does that hypothesis actually align with the data? I'm struggling to find good figures that spell this out on a region by region basis. The data are often muddied, f.e. by including lightning strikes, ladders or trucks hitting overhead high-voltage power lines, self-harm / suicide attempts, etc. For example, some Australian data for a 2-year period [1] > 55 deaths involving electrical injury - 50 male, 5 female > 8 were lightning strikes > 17 were intentional self-harm > 18 were were due to exposure to other specified electric current Either way that's about 26 / year out of a population of ~25M ~= 1 per million. In the USA I'm finding: > Electrocution is the fifth leading cause of occupational injury death > 41% of cases involved overhead power lines Alternatively [3] for USA: > Electrocution is sixth among causes of workplace deaths > Electrical hazards cause more than 300 deaths 300 out of a population of ~330M ~= 1 per million [1] https://www.aihw.gov.au/reports/injury/electrical-injuries-deaths-hospitalisations-14-16/contents/summary https://www.aihw.gov.au/reports/injury/electrical-injuries-d... [2] https://injuryprevention.bmj.com/content/8/4/306 https://injuryprevention.bmj.com/content/8/4/306 [3] https://www.electrocuted.com/safety/statistics/ https://www.electrocuted.com/safety/statistics/
    - Jedd 6y ago
      Addenda - my numbers are wrong. I was including lightning strikes in the AU numbers, but the US numbers were electrical (lines, domestic, construction, etc) only. So fatality ratios skew higher in the USA than AU, at least. The numbers are quite low in both cases, so the ostensible safety benefits of 110V at 15-20A may not be terribly compelling in practice.