Sean asked in Science & MathematicsEngineering · 1 decade ago

# how many Amps is the lethal current?

Apparently the last question about this was removed, it's a shame how something so innocent and simple as getting into circuitry raises an eyebrow. If this for some reason raises a red flag to you, because you are a self-righteous paranoid jackass, then that's your own problem you should really consider working on, not mine.

now, I will ask again, because I will be getting into project making, what is the lethal dose of amps/current I should avoid in order to benefit my safety, take note this is from someone who knows very little about engineering/circuitry/ect

and I want to make sure I don't injure myself, you know, as in avoiding injury.

is the lethal dose in mA? what's the difference between amps and voltage? apparently people were saying voltage doesn't matter in regards to safety, so what's the difference between volts and amps?

Relevance
• 1 decade ago

Voltage is the electric 'pressure", and amps measures the actual electric current flow.

The same amount of voltage will produce more amps if you are in a tub of water, than if you are on dry ground, because your electrical resistance to current flow would be less.

A lethal dose of amps depends on whether the current flows across your heart or not.

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...While any amount of current over 10 milliamps (0.01 amp) is capable of producing painful to severe shock, currents between 100 and 200 mA (0.1 to 0.2 amp) are lethal. Currents above 200 milliamps (0.2 amp), while producing severe burns and unconsciousness, do not usually cause death if the victim is given immediate attention. Resuscitation, consisting of artificial respiration, will usually revive the victim...

==edit==

...As shown in the chart, shock is relatively more severe as the current rises. For currents above 10 milliamps, muscular contractions are so strong that the victim cannot let go of the wire that is shocking him. At values as low as 20 milliamps, breathing becomes labored, finally ceasing completely even at values below 75 milliamps.

As the current approaches 100 milliamps, ventricular fibrillation of the heart occurs - an uncoordinated twitching of the walls of the heart's ventricles which results in death.

Above 200 milliamps, the muscular contractions are so severe that the heart is forcibly clamped during the shock. This clamping protects the heart from going into ventricular fibrillation, and the victim's chances for survival are good...

==edit2==

...It is common knowledge that victims of high-voltage shock usually respond to artificial respiration more readily that the victims of low-voltage shock. The reason may be the merciful clamping of the heart, owing to the high current densities associated with high voltages. However, lest these details be misinterpreted, the only reasonable conclusion that can be drawn is that 75 volts are just as lethal as 750 volts.

The actual resistance of the body varies depending upon the points of contact and the skin condition (moist or dry). Between the ears, for example, the internal resistance (less the skin resistance) is only 100 ohms, while from hand to foot is closer to 500 ohms. The skin resistance may vary from 1000 ohms for wet skin to over 500,000 ohms for dry skin...

• Ecko
Lv 7

The lethal current is often taken as 30mA, but it can be less. This applies to death caused by ventricular fibrillation, the heart going crazy basically.

An ELCB or RCD or whatever name they are known by in your region usually trips somewhere from 10-30mA, though this is also supposed to happen within 10ms.

While it is current that causes the damage, this depends on the voltage and the resistance of your skin etc - the connection you have and what path the current takes through the body, like across the chest from one hand to the other, one hand to the feet. Usually it is taken that voltages over 40V are hazardous. These are called low voltage from 40V up to 600V. Above this you are more likely to get badly (fatally) burned from high currents and energy developed. The blood is a main conductor inside the body. If the power supply is limited to a few mA it is less dangerous, but capacitors in the circuit store energy, so can still cause problems.

Voltages lower than 40V (32V AC) are normally considered "extra low voltage" in government regulations. Even lower voltages than 40V can be hazardous under certain conditions. That is because the skin resistance is very variable, and when wet with sweat or in salt water, or there is an open wound, an increased hazard (different assessment) applies.

A very useful relationship in electrical systems to look up is Ohm's law, which gives the relationship between voltage, resistance and current. I = V/R etc. Another is for power, P = V x I. Armed with these two many problems can be solved.

Voltage is the electrical pressure that forces current through a circuit. Current is the electrical flow, like a particular number of electrons (1 mole or 1 Coulomb) per second. The resistance is the resistance to electrical flow, and so a voltage will always appear across a resistance if current flows. Resistance could be called volts per amp, and ohms law is R = V/I.

The remaining version of Ohms law is V = I x R.

Good rant there, but it doesn't look like your similar question was deleted at all.

• Anonymous
6 years ago

RE:

how many Amps is the lethal current?

Apparently the last question about this was removed, it&#39;s a shame how something so innocent and simple as getting into circuitry raises an eyebrow. If this for some reason raises a red flag to you, because you are a self-righteous paranoid jackass, then that&#39;s your own problem you should...

Source(s): amps lethal current: https://tr.im/LIfTE
• 1 decade ago

Amps are a measure of how many electrons are flowing through a given point per second. Voltage is a measure of the potential difference of something. Usually measured between the device and the ground. Think of voltage as the readiness of the electrons to flow, whereas resistance acts against voltage in order to reduce the amperage. If that makes any sense at all. Technically it is the amps that kill you, but its the voltage that causes the amperage. The point being made though, is that the voltage needed to kill a sweaty man is less than the voltage needed to kill a dry man. An amperage of about 0.01 will not kill you instantly, but it may prevent you from letting go of whatever is causing the shock in the first place, and while it won't stop your heart, over a short period of time it will kill you. It will be physically impossible to let go. As far as instant death is concerned that happens at about 0.1 amps. These are slightly conservative estimates, but only slightly. If you are designing something for safety these are the numbers to have in mind. Also keep in mind that Direct Current (DC) is less dangerous than Alternating Current (AC), which in turn becomes more dangerous at lower frequencies of alternation.

Source(s): I'm a nerd
• ?
Lv 5

Geenrally speaking 30MA is taken as a figure on domestic supplies because the disconnection time for an rcd and the cycle time of a domestic supply mean that you cannot be exposed to the current for more than a few milliseconds. If you are not protected by an rcd and/or using somethign other than mains frequency supply then the level of current can be dangerous at much less than 30mA - it depends on where the current flows. Even a few milliamps can stop your heart, and then the time your heart stops determines how easily it can recover a normal beating pattern.

The best suggestion is to AVOID ANY current passing through your body. I hope your project does not directly involve passing current through your body - if you are even thinking about messing with tasers/electric shock toys etc then seriously - leave it alone. You will very likely do yourself or someone else serious harm!

• 5 years ago

For the best answers, search on this site https://shorturl.im/axG5X

An Ampere is the electro motive power that causes electrons to move inside a conductor. It is the product of an electrical force(Volt) and conductance(which has the Units of velocity). What affects the heart muscles is the amount of electronic Power(amperes)that the Human body receives from an electric shock. The amount of power that would stop the heart is one hundred milliamperes. The victim would die if the Heart is not restarted within 5 minutes. Whether a person survices a shock or not depends on the amount of conductivity the body had during the Shock at that particular voltage. Electricity can be very dangerous it is not something to fool around with. And people who dont understand it should not play with it.

• 6 years ago

FWIW, I'm an electrical engineer and I was taught that there is a sweet spot centered at roughly 100 milliamps that will typically trigger fibrillation in a human heart, but lethality is not a certainty. As other have pointed out, lower current will typically not be enough to cause significant harm, while higher currents will just begin cooking your internal organs for a while before you finally die! I also concur that conduction through human flesh begins at roughly 40 volts. btw, if you're ever forced to test a potentially live wire with your hand (possibly in an emergency or something), touch it with the back of your fingers, because current will cause your arm and hand muscles to contract, pulling your hand away from the wire. Touching with an open hand will cause you to involuntarily grasp the wire.

• 1 decade ago

Voltage doesn't matter? Of course it does!

It is voltage that dictates current flow in a resistance (your body). Check Ohm's law.

Fatality depends on where the current flows, or the damage it does. You can die of burns (see also Watt's law).

The heart is controlled by what amounts to microamps of current, which activate the muscles of the heart. The heart, indeed all muscles, are actuated by electricity (read Luigi Galvani's frog's leg experiments, in 1771).

Thus, the heart can be disrupted by mere milliamps passing through it. The ryythm is upset, the condition is called fibrillation, and the heart can no longer effectively pump blood. Without intervention, you die.

As you have absolutely no idea why your question might have been removed, YOU are the jackass. I really should not have answered. But, maybe I might save your life.

You must ALWAYS treat electricity with respect. Especially when the voltages are high!

• 6 years ago

From what I learned at school, 100mA is when current starts to be lethal. 1-10mA as current increases, it gets more painful. 1-3mA you might barely feel it, but as you get to 10mA and beyond it becomes more and more painful. Around 20mA you can't let go of a circuit due to involuntary muscle contractions. A hand to hand shock (Through the chest) is the worst kind of shock.

Every person is different however. Depending on health reasons, as well as the resistance of your skin and body. If you have heart problems, might not be a good idea to be playing with flyback transformers or tesla coils.

• 4 years ago

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