# What is the effect of voltage and amperage on a person?



## JohnJ0906

Frasbee said:


> . Someone told me amps are like the "punch", or pressure, and voltage is like the volume?


Other way around.
Amps is the actual amount of electrons moving, the voltage is the "pressure"


----------



## JohnJ0906

Frasbee said:


> Is it true that the lower the voltage, the higher the amps are?
> 
> If not entirely true, what is that dependent on?


Sometimes. It depends what you are talking about.

It is dependent upon Ohm's Law


----------



## electricista

Frasbee said:


> I always hear and read, that it's the amps that kill you.


I have heard that also and it is partially true. If the voltage is high enough it will also kill you or at least toast you. 

Don't try this but suppose you had a switch that controlled a motor and you decide to disconnect the switch and grab hold of the feed and the switch leg. if the motor controller has the motor off and you are not grounded you will not feel anything. Now turn the motor disconnect on and that motor will try to strat using your body as part o the circuit. It can be fatal with even a small amp. motor. GFI's trip at about 5 milliamps so that will give you an idea.


----------



## John

It all has to do with amperage. 

View attachment 1039


----------



## JohnJ0906

John said:


> It all has to do with amperage.
> 
> View attachment 1039


Agreed.

The amount of amperage that goes through you depends on 2 things:

1) The voltage. The higher the voltage, the higher the current.
2) Your skin resistance. The higher the resistance of your skin, the lower the current.


----------



## John

JohnJ0906 said:


> 1) The voltage. The higher the voltage, the higher the current.


1) The voltage. The higher the voltage, the higher the *potential* current.


----------



## nick

quote Frasbee]I feel like I keep asking this question, but I never get a clear cut for sure answer.

I always hear and read, that it's the amps that kill you. If its you time yes! ITS THE AMPS
Well good question as a electrician ive been electrocuted a few times i must say iam not proud of it but it was because we worked hot lots of times . And safety mistakes were made once i got 480 volts when one elbow touched a leg and my other arm touch an opposite phase leg inside of a large voltage regulator ,it was only a short second but it seemed like 2 hours of shock time and i felt that current following thur my arm chest and other arm like water flowing . Dont know the amount of current did not trip the 600amp main broke free as i fell backwards, burned skin arms were cherry red for two days . But the next time was 277V in the head went up a ladder open up a tile put my head up into ceiling and the hot a neutral was above my head 277 volts into my skull i didnt trip the breaker and that was not the best . The best was in military inside a duck tunnel working on a hv splice a tap deal hot 1400 volts dc in a mistake in commmunication it was turned on while two of us were splicen it . the 1400VOLTS DC at 100amps lost one ear cant hear i get va bennys now . i cant say enough about its effects but it hurts and its not fun . best to yas


----------



## frank

Ever made a 'shock' coil in school to to amuse your friends? We made them in Science class and held hands in a ring of 20 daft teenagers. Oscilloscope measurements showed a voltage of 30,000 ( thirty thousand volts) Since the device was fed only by a 2 volt DC battery the current was practically not measurable. So there we have the clue. It's the current that kills you. It's the voltage that makes you jump.

FRank


----------



## shunt trip

*shocked*

I agree with all the proven theories, But the lasting effect of electrocution largely depends on the route through the body & the conditions of contact.
Voltage & current also play a large factor. The damage depends on the exposure.
I know this from first hand knowledge, My father used make a short circuit loop using his finger & thumb to verify voltage at light sockets. He was so old school at this, that he would sometimes lick his finger, because his hands were so callous that he could not always feel the voltage. It drove me insane to watch him.


----------



## Frasbee

shunt trip said:


> I agree with all the proven theories, But the lasting effect of electrocution largely depends on the route through the body & the conditions of contact.
> Voltage & current also play a large factor. The damage depends on the exposure.
> I know this from first hand knowledge, My father used make a short circuit loop using his finger & thumb to verify voltage at light sockets. He was so old school at this, that he would sometimes lick his finger, because his hands were so callous that he could not always feel the voltage. It drove me insane to watch him.


During my earliest days, I did not realize they turned the power on in this room, and I was trying to adjust a receptacle, I actually (not intentionally), grabbed the receptacle by both screws, and slowly realized there was a tingling from my thumb to my pointer finger. It started to creep up into the rest of my hand when I pulled away.

So here's a follow up for clarification:

Are the volts virtually a non factor when it comes to injury? I know I'm slow on this but I just can't figure out this electricity thing.

What do you mean the higher the voltage, the higher the "potential" current?

This guy at work said the amps would stop your heart, but the voltage would cook you.

Ugh, I need to do more research on this.


----------



## shunt trip

*shocked*

Because of all the variables,(voltage, amperage, resistance, impedance, contact, moisture, static, Etc..) no one rule applies to the lasting effects. It depends on how fried you get...My dad never had any lasting effects from feeling 120vac in light sockets. 
Remember, every living thing that thinks is electric. Your brain is a micro computer that sends out millions of impulses(electric) every second. The system operating voltage is minuscule. 
The effects of overload,(Electrocution) can vary widely and may completely destroy tissue(burns,pulmonary,etc) Or may just overstimulate sensory paths.
Learn or burn. The lasting effects of electrocution are dictated by the exposure conditions. 
Each set of conditions & length of exposure will dictate injury & damage/death. :thumbsup:


----------



## nick

*Turn It Off Lock It Off Be Safe !*

Well lets look at high voltage at low amperage , some items of interest like the old Windhurst ,Vande Graff Generator or the Tesla Coil or just plain static electricity maybe the marx generator like these new stun guns a stun gun is just a voltage multiplier caps and doides some electronics to give thousands of volts to shock you but not kill you . Low current in the micro or milliamp area is some what safe but in a larger amount it will kill .Each person is different in resistance to electrocution or condition of being shocked some live to tell some dont . Take care be safe turn it off lock it off


----------



## brian john

Nick:

If you have been electrocuted how is it you are able to type. 100% of the people that have been electrocuted are in a grave yard or have been cremated. Now I have no doubt you have been shocked several times but hopefully never close to electrocution.


----------



## shunt trip

*shocked*

Brian John, good point. It is 2 different things, being shocked versus electrocuted. Although, I have heard of people being electrocuted..dead, & cpr'd "back to life"......... I would not count on it though......


----------



## nick

Well who said i could type Brian, just a bit of luck i think and not much on good common sense but i paid the price with missing my hearing in one ear you might say . I never take safety lightly anymore we lock out tag out everytime . And i type with one finger but it has nothing to do with being shocked one or twice its because i never learned how to tyupe. I work with a electrician who was struck buy lighting on a golf course down here in florida its common to get lighting storms every week in the summer months , blew out the bottom of his shoes but he is still playing golf . Brian take care best to ya


----------



## brian john

Several years ago I was severely shocked an electrician installed a CB in a tagged out cubicle.

My wife called my parents and told them I was electrocuted they damn near had heart attacks.

Nick: This phrasing is often mixed up by trades people and others.


----------



## nick

Well you are correct Brian in that statement . I tell my wife if the shop ever calls dont believe anything they tell you, just get a good lawyer and dont worry about the funneral because ill be allready cremated she can just box me up and its a lot cheaper . Best part if i go insurance pays off the house just joken Brian we had a few close ones thank god were still here most of them were before i got married . Best to yas


----------



## JamesINla

When I was in college getting my BA in electrical engineering one semister we had a professor who was also the head engineer at Xerox at the time. Anyway he was an Army electrical engineer and he would tell us stories about how guys would enter fenced off areas and just get electruded and fall dead right there. We did talk about this very topic in some detail, but it really easn't in the plan for EE. Anyhow, as mentioned it is all with respect to ohms Law. A few mA can kill a human. The number he threw out to us...and I remember this class very well...20. I was shocked (no pun intended) at how little the number was. I have always respected electricity....A bit of the theory helps...blowing up a few tools really makes a mark on ones mind.


----------



## Trimix-leccy

VOLTS JOLTS
MILS KILLS


----------



## drsparky

Voltage will not kill, current will not kill. Completing a proper circuit kills. A 480 amp car battery at 12 volts is harmless to the touch. A 12000 volt static shock from the carpet at 1 micro amp is just annoying. Of course in the right conditions (with proper resistance) together they kill.


----------



## retired 7373

Frasbee said:


> I feel like I keep asking this question, but I never get a clear cut for sure answer.
> 
> I always hear and read, that it's the amps that kill you. Someone told me amps are like the "punch", or pressure, and voltage is like the volume?
> 
> What causes you to lose control of your muscles, amps or voltage?
> 
> I was also told that volts burn, and amps kill.
> 
> Is it true that the lower the voltage, the higher the amps are?
> 
> If not entirely true, what is that dependent on?
> 
> I did some searching on-line but I just can't find proper answers to these.


 
THE HIGHER THE VOLTAGE THE LOWER THE CURRENT IN AN A/C CIRCUIT- CHECK THE FORMULA.


----------



## JohnJ0906

retired 7373 said:


> THE HIGHER THE VOLTAGE THE LOWER THE CURRENT IN AN A/C CIRCUIT- CHECK THE FORMULA.



Really?

I=E/R 

Seems to say that the higher the voltage, the higher the current. (At a fixed resistance)

If a person is shocked by 120v, then 277v, which will cause more current to flow through the body?


----------



## retired 7373

JohnJ0906 said:


> Really?
> 
> I=E/R
> 
> Seems to say that the higher the voltage, the higher the current. (At a fixed resistance)
> 
> If a person is shocked by 120v, then 277v, which will cause more current to flow through the body?


John, 
I dont have the formulas at hand any more. Check the formula for a/c power. 
10 amps at 120 volts will be 5 amps at 220 volts a/c. The higher the driving force the lower the amps. That is why power lines are so small since the voltage is so high.


----------



## JohnJ0906

retired 7373 said:


> John,
> I dont have the formulas at hand any more. Check the formula for a/c power.
> 10 amps at 120 volts will be 5 amps at 220 volts a/c. The higher the driving force the lower the amps. That is why power lines are so small since the voltage is so high.



What does this have to do with current through a human body? (See the title of the thread)

The resistance of the body is the constant. If the voltage is higher, the current is higher. Basic Ohm's law. Power has nothing to do with it.


----------



## YOUNGY

This has been my first cection at tafe


----------



## drsparky

I have a lower body resistance than a lot of people that I have worked with over the years so I am more susceptible to getting lit-up than most. My resistance is about 200,000 ohms thumb to thumb.

I=E/R

So at 120V I would receive about .0006 Amps
277V I would receive about .0013 Amps

If your body was closer to 1 Meg Ohms thumb to thumb (more common).
120V .00012 Amps
277V .00027 Amps

Of course as your skin burns off and your resistance drops until your blood and fluids boil and dry up. Also remember that in a health care setting that an Intervenes line (IV) bypasses the natural resistance and basically puts a conductor strait into the nervous system (IV fluids are salt solutions that are very conductive) that is why they are so big on grounding any stray voltages.

Chuck


----------



## Zog

There are several factors that determine the severity of an electric shock

1. Amount of Current
The amount of current that passes through the body during an electrical shock is a large factor when determining the amount of tissue damage that will occur. The table listed below shows some values and their effects.

​*CURRENT*

*60HZ*

*PHYSIOLOGICAL*​*PHENOMENA*​*FEELING OR LETHAL*​*INCIDENCE*​< 1mA​None
Imperceptible
1mA​Perception threshold

2-10mA​Sensation of shock
Not painful, muscle control maintained
5mA​ 
Ground Fault Circuit Interrupter Operates
10-20mA​Paralysis Threshold of Arms
Cannot release hand grip, victim may be thrown clear (may progress to higher current and be fatal)
20-50mA​Respiratory Paralysis
Breathing Stoppage (frequently fatal)
50-100mA​Fibrillation Threshold (0.5%)
Heart action discoordinated (probably fatal)
100-200mA​Fibrillation Threshold (99.5%)
>200mA​Tissue Burning
Non fatal unless vital organs are burned


*2.Current Path*

A vital aspect of electrical shock is the pathway through the body that the current will take. The current path will determine which tissue and organs will be damaged or destroyed. However it is important to remember that current takes all paths, the damage to the human body is not simply between the entry and exit points.Often a shock victim is spared because the current path does not pass through a vital organ. For example, a foot-to-foot path is less likely to result in fibrillation than a hand-to-hand path because there is no current flow through the heart. 

3. *Duration*
The amount of time that the current passes through the body plays a significant factor in the outcome. We discussed earlier that a 100mA shock is the value that OSHA uses as a fatal shock level, but as the duration increases the amount of current that can be fatal decreases exponentially. One-way to avoid getting stuck on a circuit is to use the back of your hand. Since AC causes the muscles in your forearm to contract, you may grasp onto a conductor upon getting shocked. By using the back of your hand, the contracting muscles may cause you to pull away. Studies have shown that at voltage levels above 2300V, an arc is drawn to the hand, causing you to retract before grasping on to the conductor or circuit part.

*4.*Body resistance
As discussed, the level of current is the factor that will determine the extent of the injury from an electric shock. But the resistance of the human body is the variable that we can control to limit the current level. Ohms law applies to human shock, the amount of current that flows through the body will be determined by the voltage the person contacts divided by the body resistance. The resistance of the human body can vary dramatically depending on several factors. Essentially it is the skin, along with such factors as area of contact, tightness of contact, dryness or wetness of the skin, and cuts, abrasions, or blisters that introduce the variables.Excluding the skin, human body resistance is about 250 Ohms per arm or leg, and 100-500 Ohms for the torso. The more muscular the person, the lower the resistance. Unless the skin is punctured, the skin will provide additional resistance. The worst-case scenario is considered to be 500 Ohms hand-to-hand. Some typical values of skin resistance are listed below.


*Condition of contact*
*Resistance (Ohms)*​*Dry*​*Wet*​Finger touch
40 k-1 M​4-15 k​Hand holding wire
15-50 k​3-6 k​Finger-thumb grasp
10-30 k​2-5 k​Hand holding pliers
5-10 k​1-3 k​Hand around pipe (or drill)
1-3 k​0.5-1.5 k​Palm touch
3-8 k​1-2 k​Two hands around pipe
0.5-1.5 k​250-750​Hand immersed
--------​200-500​Foot immersed
--------​100-300​

Using these typical values, a person can estimate their approximate body resistance. Let’s say a person grabs a wire in a 480/277V panel that they assumed was deenergized while touching the panel door with the other hand. The worker would have about:

250 ohms for the arm +
250 Ohms for the other arm +
32,500 Ohms for the skin
A total resistance of about 33,000 Ohms

277V/33,000 Ohms = 8.4 mA (Mild shock

Now lets look at the same scenario, but this time with wet or sweaty skin.

250 ohms for the arm +
250 Ohms for the other arm +
4500 Ohms for the skin
A total resistance of about 5000 Ohms

277V/5000 Ohms = 55.4 mA (Respiratory Paralysis, possible fibrillation, may be fatal)

At voltage levels above 600V, the resistance of the skin ceases to exist; it is simply punctured by the high voltage. For higher voltages, only the internal body resistance impedes current flow. At levels about 2400V and higher, burning becomes the major effect, lower voltages fibrillation and asphyxiation.

How well you are grounded is also a factor. Wearing rubber soled shoes or gloves along with the material between you and ground will add to your total resistance.  



*Voltage*
For any given voltage the current passing through a body will be equal to volts divided by body resistance, however, higher voltages affect the path due to the “Skin effect”. High voltages (>20,000V) cause current to flow primarily on the outside of a conductor therefore a shock victim from these higher voltages will see more external burns to the skin and less of an effect on the internal organs.

*Frequency*
Studies have shown that the frequency best suited for traveling through the human body is 50-100 hertz. Higher frequencies (>200Hz) also have a “Skin effect” similar to that discussed above.

*AC vs. DC*
AC and DC also affect the body in different ways. AC tends to cause a muscular contraction that can cause the victim to grab hold of a conductor while DC tends to cause a convulsion effect causing the victim to jerk away. The minimum “let-go” current for AC is about 15mA while the DC “let-go” current is significantly much higher at 75mA.


----------



## Faultfinder1

*Safe is Safe!*

If you're getting shocked you're doing something that is unsafe - voltage/amps/ohms/etc don't matter! If (hypothetically) I contacted a cable and received a "tingle" there's no saying that the same contact would not kill you. A 9V battery applied to your heart will kill you, so there is no way to actually tell how much voltage/amperage, etc will hurt you or kill you _under any specific circumstances._
The bottom line here is safety - if you started your job with the right safety attitude and didn't allow yourself to become distracted you won't get dead! 
Sorry if I sound pissy here, but too many electricians get killed every year simply because they refuse to learn and follow the simple safety rules. You seldom, if ever HAVE to work anything hot - so why are people taking these risks at all? 
I want to go home to my family at the end of each and every day, and I hate hospitals - so I take the time to do things the safest way, not the easiest way. 

www.faultlocating.com


----------

