electrocution risk

[Giacomo Lepore]

Can you help me understand something?

a colleague of mine says that:
1. with the 230 vac "be attached to the current", while the 400vac is less dangerous because "shoot you away".
2. with the continuous current there is no risk of "remaining attached" because if there is no oscillation of tension the muscles do not remain contracted.

Now, from my reminiscences I am quite certain that 230 vac or 400 vac tetanization always happens, and if you are above the release current you are shot. But it's not the first time I hear this, so maybe something real is there, just I don't understand it.

for the second point, what happens with the continuous? does tetanization happen or not? I think so, but maybe I'm wrong.

We only talk about these two aspects, all other electrocution damage (fibrillation, dissociation, joule effect, etc.) are clearer and doubtless.

 

[+forte]

we talk about current and not voltage
the biggest troubles come from the high current intensity combined with the low frequency
the continuous, if the current intensity and exposure time are greater, the same damages as the alternation

 

[bip]

the damage is given by the current intensity, and not directly from the voltage.
at the same time as all other conditions (substantially the electrical resistance of the human body), a higher voltage will result in a higher current flow, therefore greater damage.

the alternating current is more dangerous, because it has a greater tetanizing effect, substantially if you touch a tense conductor to tighten the hand, if you touch it with the palm tighten the conductor, if you touch it with the back the movement of the muscles detaches you from the conductor.
for this in case you have to go out of a burning building, with a lot of smoke, the path with the back of the hand is silent. .

 

[Giacomo Lepore]

Forgive me, my questions are not "danno", but only the effect of tetanization. the questions are two:

1. Why is ac worse than dc? What is the biological effect?

2. there is an explanation that [alcuni affermano che] Does 400vac have a different effect than 230vac? (considering that the two tensions refer to the same level of distribution, they are simply referred differently).

to simplify the thread, if you agree, I would try to give for granted the knowledge of the first ohm law. then once the conditions of contact (e.g. wet/dry hands) and the path of the current in the body (e.g. hand dx > feet), talk of current or voltage, in this area, can we consider it equivalent?

 

[bip]

1. Why is ac worse than dc? What is the biological effect?

when the body is crossed by a continuous current bears it better because it tends to "inhabit" (I admit it, it is poorly smoothed) while the alternating current, at each period gives a new stimulus to the muscles, which move to clicks of the frequency of the tension, and therefore tend to block.

2. there is an explanation that [alcuni affermano che] Does 400vac have a different effect than 230vac? (considering that the two tensions refer to the same level of distribution, they are simply referred differently).

In the case of three-phase feeding you can have a contact between phase and neutral (or more frequently between phase and earth) and therefore is perfectly equivalent to the single-phase case.
if instead the body puts in contact between them two phases (but it is unlikely, as soon as you touch the first of the two phases you tend to download to the ground, if you do not have insulating footwear) the tension to which you are subjected, and therefore the current, is greater and therefore more harmful.

I answer you with a question: what explanation is there to the fact that some people claim that the earth is flat?

 

[Giacomo Lepore]

when the body is crossed by a continuous current bears it better because it tends to "inhabit" (I admit, it is explained badly) while the alternating current, at each period gives a new stimulus to the muscles, which move to clicks of the frequency of the tension, and therefore tend to block.

Well, when you contract a muscle physiologically, you do it with a continuous current, don't you? Right?
the current variation can stress "more" muscle fibers, but if you are above the release current tetanization however happens.
However if you consider low voltage up to 1000vac and 1500vdc means that alternation is more dangerous. This is true, but it does not depend on tetanization, but on other effects.
tetanization does not kill you, what kills is ventricular fibrillation in the case of the continuous and blood dissociation of the alternating case. In the first case you die by cardiac arrest and you have to intervene very quickly. in the second case you die by embolism and a hyperbaric treatment can be done with larger times.
At least this teach us at the pes courses.

In the case of three-phase feeding you can have a contact between phase and neutral (or more frequently between phase and earth) and therefore is perfectly equivalent to the single-phase case.
if instead the body puts in contact between them two phases (but it is unlikely, as soon as you touch the first of the two phases you tend to download to the ground, if you do not have insulating footwear) the tension to which you are subjected, and therefore the current, is greater and therefore more harmful.

It was what I said. Suppose we have a phase-phase contact and then take the concatenate (if you take the starship always 230vac are... )

I answer you with a question: what explanation is there to the fact that some people claim that the earth is flat?

What he did to me is an electronic engineer. If it was the electrical equivalent of a landplanner I wouldn't be here writing.

 

[+forte]

muscle contractions and tetanization begin in the muscles of the hand and arm from 10 but on,
the overlap of the frequency of alternating current on the rhythms of nervous and circulatory systems produces an alternation that results in spasms, tremors and irregular heartbeat,
the continuous current can produce an electrolytic effect in the organism that can generate a risk of embolism or death resulting from the electrolysis of the blood

Can you help me understand something?
a colleague of mine says that:
1. with the 230 vac "be attached to the current", while the 400vac is less dangerous because "shoot you away".

It's what I've seen only in movies like mom I lost the plane, called by an electronic ing then, never heard

 

[ale47p]

I have heard this thing that the 380 shoots you away while the 220 keeps you attacked (and that the 110 is even worse) I heard it from people who work in the yard (muratories, imbianchini, electricians)

... I answer with a question: what explanation is there to the fact that some people claim that the earth is flat?

to answer here it takes a good one, indeed, a luminaire. ..psychologist sociologist and who knows what else... nice question though o_o

 

[Giacomo Lepore]

I have heard this thing that the 380 shoots you away while the 220 keeps you attacked (and that the 110 is even worse) I heard it from people who work in the yard (muratories, imbianchini, electricians)

I felt it for the first time by a guy who ran for security. the same had, however, said that the specific plant had a power of 230v and therefore I totally ignored the other stools that he said.

But if now an electronic engineer without correlation is spatial, and temporal, I repeat the same thing, some doubt comes to me.

 

[Cristallo]

I don't know one of the biological effects of the current. but I have taken it more than once :roflmao:.
never continues (but I worked with 12-24). there I peeled the threads in tension with the teeth:
Could your question be explained as reported here?http://www.elektro.it/elektro_sicurel_html/elektro_sicurel_3.html

 

[Giacomo Lepore]

I don't know one of the biological effects of the current. but I have taken it more than once :roflmao:.
never continues (but I worked with 12-24). there I peeled the threads in tension with the teeth:
Could your question be explained as reported here?http://www.elektro.it/elektro_sicurel_html/elektro_sicurel_3.html

It could be, but you don't understand what you mean by "very high". . .
2.5.1 tetanization the muscles involved in the passage of the current, it is difficult to detach from the tension part thus prolonging the contact and causing even more harmful effects - the greater value of current for which a person is still able to disconnect from the electric source is called release current and on average is included between the 10th and the 15th for a current of 50hz. Note that very high currents do not usually produce tetanization because when the body comes into contact with them, the muscle excitation is so high that involuntary muscle movements generally detach the source subject.

 

[Giacomo Lepore]

p.s.
I don't write it to you. Really. would be an insult.