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Bhruic -> RE: electric bug zappers (5/12/2014 6:33:09 PM)
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In the interest of safety based in response to the OP, here is some information I have found... do with it what you will.
From the site:
http://www.allaboutcircuits.com/vol_1/chpt_3/4.html
A common phrase heard in reference to electrical safety goes something like this: "It's not voltage that kills, its current!" While there is an element of truth to this, there's more to understand about shock hazard than this simple adage. If voltage presented no danger, no one would ever print and display signs saying: DANGER -- HIGH VOLTAGE!
The principle that "current kills" is essentially correct. It is electric current that burns tissue, freezes muscles, and fibrillates hearts. However, electric current doesn't just occur on its own: there must be voltage available to motivate electrons to flow through a victim. A person's body also presents resistance to current, which must be taken into account.
(me) Many commercially available racquet zappers that use only 2 double A batteries can deliver 2300 volts.
http://nathanthegreat.squidoo.com/best-tennis-racket-bug-zappers
Continuing on from the first site:
The amount of current through a body is equal to the amount of voltage applied between two points on that body, divided by the electrical resistance offered by the body between those two points. Obviously, the more voltage available to cause electrons to flow, the easier they will flow through any given amount of resistance. Hence, the danger of high voltage: high voltage means potential for large amounts of current through your body, which will injure or kill you. Conversely, the more resistance a body offers to current, the slower electrons will flow for any given amount of voltage. Just how much voltage is dangerous depends on how much total resistance is in the circuit to oppose the flow of electrons.
But how much current is harmful? The answer to that question also depends on several factors. Individual body chemistry has a significant impact on how electric current affects an individual. Some people are highly sensitive to current, experiencing involuntary muscle contraction with shocks from static electricity. Others can draw large sparks from discharging static electricity and hardly feel it, much less experience a muscle spasm. Despite these differences, approximate guidelines have been developed through tests which indicate very little current being necessary to manifest harmful effects.
(me) then there is a chart on the felt effects of various milliamp ratings that is worth looking at, followed by:
Keep in mind that these figures are only approximate, as individuals with different body chemistry may react differently. It has been suggested that an across-the-chest current of only 17 milliamps AC is enough to induce fibrillation in a human subject under certain conditions. Most of our data regarding induced fibrillation comes from animal testing. Obviously, it is not practical to perform tests of induced ventricular fibrillation on human subjects, so the available data is sketchy.
Remember, it has been suggested a current of only 17 milliamps may induce ventricular (heart) fibrillation. With a hand-to-hand resistance of 1000 Ω, it would only take 17 volts to create this dangerous condition.
Seventeen volts is not very much as far as electrical systems are concerned. Granted, this is a "worst-case" scenario with 60 Hz AC voltage and excellent bodily conductivity, but it does stand to show how little voltage may present a serious threat under certain conditions.
(me) Now... There are definitely different issues between AC and DC current - although the above mentioned chart shows only 500 milliamps of DC current are required to fibrillate a human heart - and there are issues of conditions of resistance and individual peoples susceptibility.
It's enough to suggest to me that the matter is not cut and dried, and people should use their own common sense when using electrical toys in the chest area. If you are young and healthy, and have no history of cardiac problems or sensitivity, you may well be able to play with zappers till the cows come home... but do not simply trust that anything you buy must be safe, or they wouldn't sell it. Manufacturers are not legally accountable when their product is used in an manner that was clearly not intended. If you put a bug zapper on your eye ball, it is going to do damage, and the manufacturer will not be legally accountable.
Cheers
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