I assume that with double voltage the current is double at a given resistance. Normally ground fault circuit interrupter (GFCI) secures power lines - so if the fault current is double the GFCI will break the line earlier and in shorter time.
> I was just wondering about what some people say
> that it's better to get shocked by 220V rather than 110V.
> Is this true?
> And why?
I can't say as I've ever heard this. I've felt both, and neither
is a party.
Were I to hazard a guess, I might suggest that it has to do
with the 1/10/100 rule: 1 mA hurts, 10 mA will disrupt the
cardiac cycle causing all kinds of nastiness that can lead
to death, and 100 mA won't disrupt the heart, but it will
cook tissue. Maybe 220V power is more likely to put the
current above the cardiac disruption level?
At any rate, I treat everything above ~24V (AC or DC) as
somewhat dangerous, and anything connected to any
power as potentially dangerous, even if I'd have to be
soaked in salt water to get a shock. Better safe than
sorry.
> Maybe 220V power is more likely to put the
> current above the cardiac disruption level?
ISTR from the recent thread on 12VDC shocks that very
high voltages are more likely to put the whole heart into
shock (like hospital defib paddles, which basically "reset"
the heart's electrical system), whereas lower voltages might
cause fibriliation to just some parts, which is more dangerous,
as then those parts of the heart are out of synch with others.
Or something like that. I'd have thought 220V is not high
enough, and under the right conditions 110 and 220 will
kill, especially 220
If 220 is somehow more dangerous than 110, then there will be
statistics (i.e., excess death rate from electrocution) to show that.
Are there such statistics? Do more people die from electric shock in
the 220 countries?
> > Maybe 220V power is more likely to put the
> > current above the cardiac disruption level?
>
> ISTR from the recent thread on 12VDC shocks that very
> high voltages are more likely to put the whole heart into
> shock (like hospital defib paddles, which basically "reset"
> the heart's electrical system), whereas lower voltages might
> cause fibriliation to just some parts, which is more dangerous,
> as then those parts of the heart are out of synch with others.
> Or something like that. I'd have thought 220V is not high
> enough, and under the right conditions 110 and 220 will
> kill, especially 220
>
Perhaps it should be noted that in the main 220 - 250v countries tend
to have a 50Hz
frequency, to which the human body is more susceptible, than the
110-120v countries that
tend to be 60Hz.
Legally in most countries high voltage is above 48v (AC or DC). If
the conditions are right
only a mere 15mA passing through the body can have dangerous effects.
Average, falling, also ~ < 1 per million population
So you'd conclude no significant difference between 110 and 220
when it comes to lethality, if you assume safety standards, health-
care and usage are similar
> If 220 is somehow more dangerous than 110, then there will be
> statistics (i.e., excess death rate from electrocution) to show that.
> Are there such statistics? Do more people die from electric shock in
> the 220 countries?
Statistics is not that easy. The death rate would be influenced by many
other factors, some of which might be more important than the voltage.
Like: the climate. In a very dry climate the risk is probably much lower
than in a wet climate (lower body resistance). OTOH people in a wet
climate might be more inclined to wear rubber boots, which would
definitely reduce the risk. The way house wiring is done, whether
safety-earth and/or differential-current safety breakers are manadtory
and lots of other technical details would also have a lot of influence.
Wouter van Ooijen
-- -------------------------------------------
Van Ooijen Technische Informatica: http://www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: http://www.voti.nl/hvu
Well then, what fact about the world would constitute evidence that
high voltage is better (or worse) than low voltage? Where would you
look, if you don't look at death rate from electrocution?
> > If 220 is somehow more dangerous than 110, then there will be
> > statistics (i.e., excess death rate from electrocution) to show that.
> > Are there such statistics? Do more people die from electric shock in
> > the 220 countries?
>
> Statistics is not that easy. The death rate would be influenced by many
> other factors, some of which might be more important than the voltage.
> Like: the climate. In a very dry climate the risk is probably much lower
> than in a wet climate (lower body resistance). OTOH people in a wet
> climate might be more inclined to wear rubber boots, which would
> definitely reduce the risk. The way house wiring is done, whether
> safety-earth and/or differential-current safety breakers are manadtory
> and lots of other technical details would also have a lot of influence.
>
> Wouter van Ooijen
>
> -- -------------------------------------------
> Van Ooijen Technische Informatica: http://www.voti.nl
> consultancy, development, PICmicro products
> docent Hogeschool van Utrecht: http://www.voti.nl/hvu
>
>
> www.parliament.the-stationery-office.co.uk/pa/cm200506/cmhansrd/cm050
> 627/text/50627w30.htm
>
> US stats, Consumer Product Safety Commission
> (Google - electrocution us statistics)
>
> http://66.102.7.104/search?q=cache:X_OOBsum1S0J:http://www.cpsc.gov/library/shock98
> .pdf+electrocution+us+statistics&hl=en
>
> Average, falling, also ~ < 1 per million population
I make this 1 per 0.52million for the 10-year average, 1 per 0.55million for the last year given.
> So you'd conclude no significant difference between 110 and 220
> when it comes to lethality,
I don't see this from the data at all! Turning round the last year's data, that's 0.42 per million in the UK,
1.83 per million for the USA - about 4x as many on 110V as on 230V.
> if you assume safety standards, health-care and usage are similar
And this assumption isn't valid, of course. US/UK standards are very different indeed, and this may explain
some of the difference in the data. (Just as a single example, sockets aren't allowed in bathrooms here,
except for special "shaver sockets" which have an isolating transformer built in and only handle a couple of
amps - a fact that annoys my girlfriend, as she has to dry her hair in the bedroom, rather than the bathroom
as she does at home in New York! :-)
I don't think the statistics show that 230V is "safer" than 110V, I think the figures are too small and the
other differences are too great to ignore. For the record, a former colleague of mine died about 4 years ago
when he was standing in a pond in his garden trimming the lining, when he cut through the cable supplying the
pump - this is obviously a case where the impedance to Earth was low, but when I was a kid the son of the
local sweet-shop owner was apparently in bed, changing the bulb in a light above it, and he was killed. in
this case the path to Earth is less obviously a good one, but it was good enough, sadly. When I look back at
what I did when I was a teenager (wiring up a darkroom from scratch in a cellar, at the age of 14!) I'm a bit
amazed that I got through it unscathed!
Assumptions I used in my calculations: UK population 60million, US population 300million - these are rounded
somewhat, but aren't far off.
On Sun, 20 Nov 2005 01:03:11 -0800, Neil Baylis wrote:
> Well then, what fact about the world would constitute evidence that
> high voltage is better (or worse) than low voltage? Where would you
> look, if you don't look at death rate from electrocution?
I don't think anyone said that high voltage was safer/less safe than low - it was specifically about 110V vs
230V because it isn't a linear relationship - the physiological effects are much more complex than that.
People have survived being struck by lightning, and have died from licking a 9V battery, so Ohm's Law isn't
anywhere near enough to explain it.
The only way to prove it conclusively would be properly controlled scientific experiments, but that isn't
going to happen. And regardless of the results, countries wouldn't change their supply voltage because the
benefit doesn't justify the huge cost (and unpopularity for the politicians involved), so we just have to
accept that we won't know for sure either way.
> I make this 1 per 0.52million for the 10-year average, 1 per
> 0.55million for the last year given
I'll give you that one, I didn't study it too hard
> > So you'd conclude no significant difference between 110 and
> > 220 when it comes to lethality
> I don't see this from the data at all !
Well, looking at the trend I call it not significant. But we can agree
to disagree. As you point out, the numbers are small and annualy
variable
What would complete the picture is to know how many people
WEREN'T killed (ie the number of fatal and non-fatal incidents).
That would be the true indicator of how lethal each voltage is. And
a non-fatal incident is most unlikely to be reported, so we'll never
know for sure
"The only way to prove it conclusively would be properly controlled
scientific experiments, but that isn't going to happen"
I'm sure there are regimes around the world who would be willing
to conduct such experiments for the right price
>>> If 220 is somehow more dangerous than 110, then there will be
>>> statistics (i.e., excess death rate from electrocution) to show that.
>> Statistics is not that easy. The death rate would be influenced by many
>> other factors, some of which might be more important than the voltage.
> Well then, what fact about the world would constitute evidence that high
> voltage is better (or worse) than low voltage? Where would you look, if
> you don't look at death rate from electrocution?
I think death rate from electrocution would be a suitable measure. But you
can't just take different rates associated with different voltages and
compare them and then conclude what's safer.
The problem with applying science (Popper style and similar) to humans is
that we are somewhat reluctant to /really/ do it... run experiments, reduce
variables, all that kind of thing we do to dead matter (and some degree to
animals).
So the proper (Popper) way would be to take a large enough sample of the
human species and put it into a controlled environment. Create that
environment so that the most common variables besides the voltage that
influence the accidental electrocution rate are the same for all HUTs. Then
leave the sample long enough in that environment to get statistically
relevant data.
Just kidding... halfway, at least. Anyway, you'd have to analyze (analyse?)
the known statistics and try to create an image of the rates and how they
relate to the different factors that might influence them and their
statistics. Maybe you can get a trend out of it, but you surely need a
sample size of measurements (that is, independent statistics) that is
bigger than just two. This is how generally the sciences (or "sciences")
related to humans work, for lack of proper experimenting.
You also could go by personal preference. Of course this means that you'd
have to create a large enough body of experience with either, in different
situations. If we really get reborn, and if you can keep this up for a few
life cycles, you actually might get somewhere with this.
> Well then, what fact about the world would constitute evidence that
> high voltage is better (or worse) than low voltage? Where would you
> look, if you don't look at death rate from electrocution?
You seem to think that evidence does exist, and it is only a matter of
finding it. There won't be any real (double blind volunteer-based)
evidence. At least, that does not seem likely to me, I would certainly
not volunteer. So you'd have to hunt for the (probably small) amount of
cases that are compareable. And be carefull about investiagtions that
might have a hidden agenda (for instance sponsored by 100V or 240V
companies or countries).
Wouter van Ooijen
-- -------------------------------------------
Van Ooijen Technische Informatica: http://www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: http://www.voti.nl/hvu
--> I don't think anyone said that high voltage was safer/less safe
than low - it was specifically about 110V vs 230V because it isn't a
linear relationship - the physiological effects are much more complex
than that. <--
Yes of course. I was merely using the terms 'high' and 'low' as
shorthand for the voltages mentioned in the question.
--> The only way to prove it conclusively would be properly controlled
scientific experiments... <---
Perhaps. I was just wondering what kind of already existing evidence
could possibly lead to an answer to the original poster's question. He
was asking us if someone's opinion about the voltages was true, and
why. The only such evidence I could think of would be if there was an
excess death rate.
Wouter wrote:
--> You seem to think that evidence does exist, and it is only a matter of
finding it. <--
I'm sorry if that's what I seemed to say. I do not think that such
evidence exists. It's just the only thing I can think of that would
(if it did exist) lead to an answer to the original poster's question.
--> There won't be any real (double blind volunteer-based) evidence. <--
Of course. Speculating about some experiment that would be conducted
in the future doesn't help, because the speculation won't provide an
answer now, or maybe ever.
I think that the best answer we have for the original poster is that
there is no evidence strong enough to lead one to conclude that high
voltage is 'better' or 'worse' than low, in general.
It is also important to consider the circumstances.
Where 230V is sued, there are usually better hardware used than they tous ususally used for 110V systems.
( Considering fire hazard there might also be a difference.
>From what i have seen on broken things comparing 24VDC and 230VAC (OK this is also AC versus DC) bad contact on 24VDC systems more easily lead to fire by overheating, while it seems on 230V systems it arcs either open, or welds together. But that might wel be just coincidences i have seen. )
> It is also important to consider the circumstances.
> Where 230V is sued, there are usually better hardware used
> than they tous ususally used for 110V systems.
I am often amazed at the wiring I see in other countries: uninsulated
wires in the air, only just outside reach of a tall person standing on
the shoulders of a ditto person, or between insulator post within a
cardboard double wall. In my country houshold wiring is supposed to be
double isolated: isolated wires within PVC tubes.
Wouter van Ooijen
-- -------------------------------------------
Van Ooijen Technische Informatica: http://www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: http://www.voti.nl/hvu
> Did the statistics specify the number of IDIOTS electrocuted?
Nobody, not even idiots, are idiots in a eulogy. Coroners prefer
"death by misadventure"
I've had only one close call, and that was purely accidental. I was
removing strip lighting from a friend's business before a move (it
was her lighting BTW !!). All the power was turned off, but I got
thrown off the step ladder when I cut through the wire on a fixture
The reason ? - its switch was actually connected to the business
next door's power, as I found out in the attic. The wall switch was
off, so I assumed that the light was not on because the fuse was
pulled, like all of the dozen other lights were off with their switches
on
Dumb luck and an unfortunate (but I'd say not unreasonable)
assumption on my part
**useful** statistics about actions leading up to electrocution
by 110 and 220 are probably hard to find and compare, just be
careful with the damn stuff
> The reason ? - its switch was actually connected to the business
> next door's power,
Just not her power :-).
Wherever possible I short the "dead" wires together before adventuring
with them. I also avert eyes when doing this as sometimes it does
prove what you are testing to disprove. .
I have had many close calls over the years.
Phase on earth (!), phase on neutral, ring feed (illegal in NZ, common
in UK), miswired socket and miswired plug so case is at phase only
when two are used together, ... .
I've had quite a few mains shocks, a few RF burns, a few HV DC (up to
about 1200 V) ..., various inductive kicks, 50v on backs of hands
while running telephone mdf jumpers is annoying (trainee engineer
days), ... . Haven't had a mains shock for years (decade(s)?). Still
alive but many of the above could have killed me. (Some would say this
list explains why I am as I am, but I assure you that such a simple
explanation is inadequate :-) ).
So - ALWAYS assume it's live. Make sure it's not. Then assume it is.
Then short it :-).
> So - ALWAYS assume it's live. Make sure it's not. Then assume
> it is. Then short it :-)
Well, I did short it - with the (expensive ;-(( ) cutters. Which alas
are not very good cutters now. The huge flash and bang was what
threw me. The insulated grip meant I didn't get a shock, although
I could've broken my leg or worse flying off the step ladder. But
it was just one of those things. You've done half-a-dozen removals
and have no reason to suspect that number 7 has teeth
Much as James discourages the word, the guy in #2 is an idiot
> Phase on earth (!), phase on neutral, ring feed (illegal in NZ, common
> in UK), miswired socket and miswired plug so case is at phase only
> when two are used together, ... .
>
Russell,
Are you sure that Ring feed is illegal in NZ? I though it was OK provided that
1 There is a common circuit breaker (Earth Leakage device ?) for both legs.
2. Fused plugs are used (as per UK).
3. Cables / connectors etc are rated appropriately.
4. Ground connection is included. (unswitched)
> > The only way to prove it conclusively would be properly
> > controlled scientific experiments, but that isn't going to happen
> I'm sure there are regimes around the world who would be willing
> to conduct such experiments for the right price
Howard, did you ever used to watch "Have I Got News For You" ?
I remember Alan Coren (Punch editor and all-round wit) being
asked the question as to why Augusto Pinochet took refuge in
the UK. Coren's answer was that he preferred Britain's higher
voltage - it got confessions so much quicker
On 11/20/05, Neil Baylis <neil.baylisspam_OUTgmail.com> wrote:
> Well then, what fact about the world would constitute evidence that
> high voltage is better (or worse) than low voltage? Where would you
> look, if you don't look at death rate from electrocution?
Unfortunately the 0.4KV (3 phase 380V or one phase 220V to the ground)
is not the only voltage at which you may die by electrocution. The
same remark for the countries using 120V to ground. There are also
aerial and underground AC lines using 6kV, 10kV, 20kV, 30kV, 110kV,
220kV, 400kV and 700kV.
There are also aerial DC lines using 27kV (on train railway).
You'll be surprised to found there are many deads because of these.
So your study about death rate on 120V or 220V could be totally
irellevant when a newspaper or a TV editor does not know the
difference between a "high voltage" electrocution and a "low voltage"
one. Everything is spinach in their had.
> > > The only way to prove it conclusively would be properly
> > > controlled scientific experiments, but that isn't going to happen
>
> > I'm sure there are regimes around the world who would be willing
> > to conduct such experiments for the right price
>
> Howard, did you ever used to watch "Have I Got News For You" ?
Oh yes, I still do - it's on at the moment on Fridays. I still think it's a shame that Angus Deaton got axed
as presenter.
> I remember Alan Coren (Punch editor and all-round wit) being
> asked the question as to why Augusto Pinochet took refuge in
> the UK. Coren's answer was that he preferred Britain's higher
> voltage - it got confessions so much quicker
Ah yes, I remember that! I think we found a way to send him back in the end, didn't we?
I have heard of some Brain-strain 'electrician' (i use the term loosely)
who wrapped the 'spare' cable round and round metal conduit in a refit
of a Woolworths store,and turned all the strip light casings 'live';
the ultimate home wound transformer!
{Original Message removed}
when working on old TV's which always ran HOT,and developed 'dry joints'
we where told unplug the mains,DISCHARGE any high capacity caps,
and if removing a tube (CRT)discharge that with a10k resistor.
On the one occasion i ignored this advice i touched a charged cap with the
tip
of a screwdriver and literally blasted it off; it certainly woke me up...
{Original Message removed}
costarricense.cr>
