Voltage, Wattage

jpanhalt

Joined Jan 18, 2008
11,087
This line of questioning is silly and nonproductive. Your question about electric shock has been answered.

DON'T TRY IT.

It is against forum rules to suggest anything dangerous, and that is exactly what you are asking about doing.

John
 

wayneh

Joined Sep 9, 2010
17,496
I don't think it's silly at all to want to understand the risks one is placing before themselves. Of course we want to avoid all risks, but it's prudent to gauge the scale of those risks.

Briefly touching 240v (or even 120v) AC terminals with your fingers is extremely unpleasant. Most folks will jump or jerk, just like touching a hot stove. It's not likely fatal for most people most of the time - I've done it and am here to tell of it. But it's like drunk driving - the odds of something really bad happening are much higher. If you couldn't let go, or have a heart problem, for instance, it could well be fatal. You cannot rely on fuses or circuit breakers to protect you, so you MUST take precautions to eliminate chances of contact.

One of the most likely causes of accidental contact, in my experience, is when plugging into a receptacle. There is a moment when the prongs have made contact and are "hot", but are not yet fully inserted. If your fingers slip forward at that moment, blammo, they hit the exposed prongs and give you a shock you'll never forget. Cleaning out a live lightbulb socket - for instance after a bulb has broken off in the socket - is another bad move you'll remember.
 

bribri

Joined Feb 20, 2011
143
I don't think it's silly at all to want to understand the risks one is placing before themselves. Of course we want to avoid all risks, but it's prudent to gauge the scale of those risks.
i completely agree.
i might add that electricity always wants to move from higher to lower voltage. translated to real-world: electricity always wants to move to the ground. your physical person does NOT want to be singled out as a path to ground. in your hypothetical scenario Lightfire, your physical connection to ground would be a significant factor.
even if isolated enough from ground, to become part of such an AC circuit could well involve pain, burns, shock (in almost every sense of the word) and, as it has been pointed out, could well be fatal.
line AC circuits use components which can handle the amount of power they are exposed to. the human body is not rated be be within those specs.


Thank you beenthere for the reference. A shuffle sounds reasonable or even a two-legged hop. Many people find it difficult to hop on one leg controllably. It is a common test in physical diagnosis. Falling on one's hands while trying to hop on one foot sounds like one of the worse positions to be in.
well yes. you might consult a kinesthesiologist on this, but the feet-together-hop or shuffle-to-safety seems the best advice to me also. my crew of fit young lads would probably be fine on one leg, but knowing the nature of the actual dangers would of course be the best protection.
after reading up on the subject of step-potential a bit, i noticed that emergency responders may eperience a 'tingling in their groins' as being evidence of having to move back from a situation involving downed powerlines.

anyway.
respectfully.
i feel that i am in no way overreaching the grounds of civility, to expect from you (jpanhalt) a basic acknowledgment of the fact that what i was saying, and what you were actively ridiculing, is in fact an established truth of the matter.
i really don't care about contextualizing such an acknowledgment as being 'apology' or 'manning-up to being wrong', it's just a question as to whether i should respect anything and everything you have to say in the future or not. no big deal.
 

beenthere

Joined Apr 20, 2004
15,819
The situation is analogous to electrofishing. One charges the water to attract fish into the field and to render them unconscious through electronarcosis.

Missouri uses DC. The boat hull is the cathode, giving a low impedance through the large area. The anode is typically a set of chain or braided wire droppers hung from insulated poles 8 to 10 feet ahead of the bow (the boat is usually a jon boat with a square bow). The smaller area of the anode means that the voltage gradient increases rapidly close to the anode.

A fish will not become unconscious until it has swum close to the anodes, where he will pop to the surface to be netted for sampling. A powerline on the ground will exhibit this steep potential gradient close to the earth contact. In the case of people, it is fatal. But, the less distance bridged by the body, the less voltage gradient encountered. The shuffle sounds safest.
 

jpanhalt

Joined Jan 18, 2008
11,087
i feel that i am in no way overreaching the grounds of civility, to expect from you (jpanhalt) a basic acknowledgment of the fact that what i was saying, and what you were actively ridiculing, is in fact an established truth of the matter.
i really don't care about contextualizing such an acknowledgment as being 'apology' or 'manning-up to being wrong', it's just a question as to whether i should respect anything and everything you have to say in the future or not. no big deal.
Sorry and respectfully, no apology. I was reacting to your statement that the person should hop away on one foot. Perhaps, I did not express myself clearly as I could have that it was the one-foot hop that I was criticizing most.

You did not offer other options like shuffling or hopping with both feet.* Obviously, reducing the potential difference between the feet is important. However, even in the best of conditions, many people cannot hop on one foot controllably for any distance. Considering that a downed power line often occurs when conditions are far less than perfect (e.g, open muddy ground, uneven terrain, wet surfaces), a suggestion to clear the area by hopping on one foot becomes even less reasonable to the point of silliness. If you have ever seen picnic events, like one-legged races, you should have noticed that a majority of untrained adults fall before getting very far.

I am amazed that you have waited this long to express your concerns. I surely hope you have not been stewing over it all this time. That is not healthy.

John

*I am not recommending hopping on both feet either, unless one is sure he can do it. It is not particularly stable. Obese and older people simply can't do that either.
 

bribri

Joined Feb 20, 2011
143
The situation is analogous to electrofishing. One charges the water to attract fish into the field and to render them unconscious through electronarcosis.
wauw. sounds effective!
is it legal where you're at? i knew a bunch of 'occasional spot-fishers' who used high-lux lamps to bag their fish dinners at night. if caught they'd have got their fishing licenses pulled instantly and been slapped with serious fines! but from all reports it was like shooting ducks in a barrel : /

The shuffle sounds safest.
i concur, all be it that being the slowest mode of escape. what really freaks me out is the testimony on 'jumping from equipment' within the literature. a high-wheeled truck is one thing, but in my job, our band covered the plains in a '74 corolla...with 13" tires! if we'd hit a problem in that piece of crap, i think the best medicine would be to stay put in our little faraday cage and wait for help... that thing was so low to the ground it was practically touching it at most time 0.o
 

magnet18

Joined Dec 22, 2010
1,227
Hi there.
Just wanting to point out that the source of the voltage will matter somewhat. I have a little transformer for old neon tubes that's current limited at 18mA (don't know if you know about current yet, its the number of electrons that go through the wire in a second). While this is a higher voltage, it's a lot less dangerous than the 120V from an outlet, which can be a very high current. (but it will still wake you up when you get tired and forget not to grab the bottom of it... that was fun:p)

If you're going to try to get 120VDC from car batteries, this will be very dangerous because they are designed to put out large amounts of current (hundreds of amps).

Voltage itself is not what is dangerous, it is the current that will hurt you. But where there is voltage, there is current, and the higher the voltage, the less current needed to kill you. Also, your body is mostly saltwater, a good conductor, so it will allow large amounts of current to pass through without doing anything to stop it. This means for safety reasons you can assume that the maximum amount of current possible from the source could flow through you.
 

K7GUH

Joined Jan 28, 2011
190
For the purpose of this discussion, consider the human body as if it were a 25 ohm 1/4 watt carbon resistor. Using your vast knowledge of Ohm's Law and the Power Formula, figure out whether AC or DC will make you deader, and proceed accordingly. The one hand rule is excellent advice, has even made it to the professional exams for X-ray technicians. Follow it meticulously.
 

bribri

Joined Feb 20, 2011
143
I am amazed that you have waited this long to express your concerns. I surely hope you have not been stewing over it all this time. That is not healthy.
"this long" being equal or less to 24 hours might be cause for question as to what might be deemed healthy.
believe it or not i've had actual real-world issues to attend to in the interbellum. from now on i'll just personally try to judge the merit of each and every post you make on its actual content and not on some notion of what i deem your ideological affiliations to be. i hope that you would do the same for me.
that said, i'm not holding my breath.

*I am not recommending hopping on both feet either, unless one is sure he can do it. It is not particularly stable. Obese and older people simply can't do that either.
perfectly reasonable. i couldn't agree more.
but if i do happen to catch you making reference to the 'darwin-awards' in the future i may find just cause to quote you ; )
 

Thread Starter

Lightfire

Joined Oct 5, 2010
690
OK. about electrofishing.

Um, what is that? I heard that many times and I also heard that it is not allowed to use. But I am thinking how can a battery can kill a fish? I know there's an apparatus. But how? No, I am just wondering don't think for anything else. I won't use that!
 
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