What would be an intelligent responce?

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jwelectric

Senior Member
Location
North Carolina
It is not an untrue statement but it is hardly a complete statement.

It is voltage, it is current, it is time as Brian pointed out and I bet other factors as well.


Again it is not an either / or type question.

The question
What would be an intelligent responce?
It aint the voltage, it's the amps that kills ya.

The answer
This is true. It is not the amount of voltage that kills but the amount of current that kills.

If 100millamps passes through the body it could be fatal at 120 volts or 25,000 volts. The voltage is variable but the current is all but fixed at 100 milliamps. This means that it is the current that kills not the voltage.

The resistance of the body is a variable. Under normal conditions the average resistance of an average male would be between 3 to 5 thousand ohms, but a hard working person on a hot day could be a little as 300 ohms but the amount of current is still 100 milliamps. Once again it is the current not the resistance that is the key to the effects.

The amount of time is a variable. Be it one nanosecond to a couple of seconds but the amount of current is the same, 100 milliamps. If in one nanosecond the current reaches 100 milliamps it could be fatal. If at two seconds the current doesn?t reach 5 milliamps a GFCI device will not open. Again the amperage is what is doing the damage.

I agree that voltage has to be present for some amount of time but unless the current is enough to cause death then it will not be fatal. The key being the amount of current and everything else is variable.
Therefore it is not the voltage, it is not the resistance of the body, it is not the amount of time but it is the amperage that does the damage.

Yes the amount of voltage, resistance of the body, and the amount of time is proportionate to the amount of current but it is the current that does the damage and everything else is variable.
 

templdl

Senior Member
Location
Wisconsin
Simply stated it is my understanding that it's the current that kills you.
BUT, the current is determined by the applied voltage which now ohms law must be included in the equation.
I= E/R.
You will note that if one were to keep the voltage constant and change the resistance the current will change which would make it posible that where one person could be electrocuted to the point of death and another may only get a mild shock.
You will note that should the voltage be increased on the person who got the mild shock the current would increase which would more likely cause serious shock to that person.

Botton line is that there are so many variables that must be taken into consideration.

As such, does voltage kill? Not directly and the severity of the shock would be dependent upon the magnetude of the voltage when combined with the resistance which results in current that can be great enough to kill.

This was taken from an MC&M article:
Electric sensation
Tingle sensation occurs at about 0.25mA to 0.5mA for an adult female and between 0.5mA and 1mA for an adult male.

Uncomfortable sensation
Current greater than 1mA to 2mA is very uncomfortable to either gender.

Maximum let-go level
The maximum let-go threshold level for a female is about 9mA and about 15mA for a male.

Fibrillation level
This is a function of current over time. For example, you will get fibrillation with 500mA over 0.2 sec or 75mA over 0.5 sec.

Let-go threshold
This is the current level at which humans lose muscle control; the electricity causes muscles to contract until current is removed.

According to IEEE Std. 80, you can determine the maximum safe shock duration by the formula, T=0.116?(E?R), where T is duration in seconds, E is the electromotive force in volts, and R is resistance of the person, which is a constant 1,000 ohms (see Figure).

For a 120V circuit, maximum shock duration=0.116?(120V?1,000)=1 sec
For a 277V circuit, maximum shock duration=0.116?(277V?1000)=0.43 sec

The following information was taken from: http://www.highvoltageconnection.com/articles/ElectricShockQuestions.htm

The Electric Shock Questions
Effects and Symptoms
Evan Mayerhoff

High Voltage Connection, Inc.

Table 1 Shock Physiological Effects

Electric Current
(1 second contact)
Physiological Effect
Voltage required to produce the current with assumed body resistance at 100,000 ohms and at 1,000 ohms

1 mA Threshold of feeling, tingling sensation. 100 V At 100,000 ohms and at 1v at 1,000 ohms

5 mA as the Accepted as maximum harmless current, 500 V and at 5 V

10-20 mA is the Beginning of sustained muscular contraction ("Can't let go" current.) 1000 V and at 10 V

100-300 mA Ventricular fibrillation, fatal if continued. Respiratory function continues. 10,000 V and at 100 V

6 A Sustained ventricular contraction followed by normal heart rhythm. (defibrillation). Temporary respiratory paralysis and possibly burns. 600,000 V and at 6000 V
 

rt66electric

Senior Member
Location
Oklahoma
what color is the HOT one???

what color is the HOT one???

When I am asked " which color is the hot one" I reply "ELECTRICITY IS COLOR-BLIND It does't make a durn what color the wire is... be careful, check it.
 

pfalcon

Senior Member
Location
Indiana
A Van de Graaff generator can put out about 100,000V or more. A Taser about 25,000V. However, both of these devices are constant current (low current at that).

It's the current that kills you.

Um, no. Once again, it is the POWER delivered that kills you. Both the Van de Graaf and the Taser have limited power output. For those special cases you have to run the equations backward. Max current = sqrt(Power/Resistance).

To be electrocuted you require sufficient Voltage to overcome resistance thus allowing the Current to begin. Then you need sufficient Power to affect the tissues. Lower power is required to create fibrillation.

It would be better said that you need threshold voltage and sufficient power.

Instead of the Van de Graaf generator, try an industrial capacitor sometime. All voltage and no current or current source. It'll blow the fingers off your hand.

When I was in high school I was involved in an experiment where I let around 20,000 volts conduct over my body. This voltage was introduced to my body not once but several times in that one 55 minute class. This voltage was at a very high frequency and the event would last for several seconds at a time.

Prolly need more information on this experiment. Two principles are probably at work: Power-limited supply and High-Frequency. High frequency travels surface-only, not through the tissues. That is until dielectric breakdown occurs.
 

iwire

Moderator
Staff member
Location
Massachusetts
The question
What would be an intelligent responce?
It aint the voltage, it's the amps that kills ya.

The answer
This is true. It is not the amount of voltage that kills but the amount of current that kills.

Mike, it is many things, it is not one thing.


Here is an electric motor.


Single_three_phase_ac_asynchronous_electric_motors_IMB34.jpg


I ask you, what makes it turn? Is it the current or the voltage?

If you can get it to turn with just one of those two things than I will agree that only one of those things is needed to kill someone.
 
Um, no. Once again, it is the POWER delivered that kills you. Both the Van de Graaf and the Taser have limited power output. For those special cases you have to run the equations backward. Max current = sqrt(Power/Resistance).

To be electrocuted you require sufficient Voltage to overcome resistance thus allowing the Current to begin. Then you need sufficient Power to affect the tissues. Lower power is required to create fibrillation.

It would be better said that you need threshold voltage and sufficient power.

Instead of the Van de Graaf generator, try an industrial capacitor sometime. All voltage and no current or current source. It'll blow the fingers off your hand.



Prolly need more information on this experiment. Two principles are probably at work: Power-limited supply and High-Frequency. High frequency travels surface-only, not through the tissues. That is until dielectric breakdown occurs.


This probably demonstrates how poorly electricity is understood and that there may well be enough behavioral distinctions between those unique manifestations that we collectively call electricity that would deserve naming them differently.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
It's energy that kills you. You can't be killed without all three of the following: voltage, current, time. Multiply those three things and you have energy.
 

Barndog

Senior Member
Location
Spring Creek Pa
I am reminded of what my high school Electronics teacher said. Think of electricity as water in a pipe. The voltage is the pressure of the system, current is the flow of water and Resistance is the size of the pipe. i agree that you need all three of these to create a shock But in the simplest form it is actually the amount of current flowing through your body that would cause death.
 

jwelectric

Senior Member
Location
North Carolina
Mike,If you can get it to turn with just one of those two things than I will agree that only one of those things is needed to kill someone.
Bob

I am not saying that one can have current without voltage. What I am saying is, it is the current that causes the ill effects ranging from uncomfortable to death.

As has been posted by others including those who want to add time to the equation current is what does the harm. Read this post http://forums.mikeholt.com/newreply.php?do=newreply&p=1316425 and the link therein and see what the different levels of pain are at what current levels. Notice that the current level for the pain being felt stays the same although the voltage changes from high to low and the time changes with the voltage level.

I agree that voltage must present for a certain amount of time but it is the current level in all cases that remains the same. Wonder why that is? It is because current not voltage, current not time that kills.

True the higher the voltage the more current that can be pushed through the human body. True the more time that the current is flowing through the human body the lower the resistance and the higher the current but it is still the current level that causes the damage not the voltage level nor the amount of time.
 

iwire

Moderator
Staff member
Location
Massachusetts
Bob

I am not saying that one can have current without voltage. What I am saying is, it is the current that causes the ill effects ranging from uncomfortable to death.

As has been posted by others including those who want to add time to the equation current is what does the harm. Read this post http://forums.mikeholt.com/newreply.php?do=newreply&p=1316425 and the link therein and see what the different levels of pain are at what current levels. Notice that the current level for the pain being felt stays the same although the voltage changes from high to low and the time changes with the voltage level.

I agree that voltage must present for a certain amount of time but it is the current level in all cases that remains the same. Wonder why that is? It is because current not voltage, current not time that kills.

True the higher the voltage the more current that can be pushed through the human body. True the more time that the current is flowing through the human body th[e lower the resistance and the higher the current but it is still the current level that causes the damage not the voltage level nor the amount of time.

Mike, as always you can never just answer the question asked. Here is the question again rephrased for clarity.

What makes an electric motor turn, is it the current or the voltage?
 

jwelectric

Senior Member
Location
North Carolina
Mike, as always you can never just answer the question asked. Here is the question again rephrased for clarity.
What makes an electric motor turn, is it the current or the voltage?
When the first electric motor was patented it patented as a revolving transformer. It is magnetic induction that makes the motor turn.

In order to have magnetic induction there must be electron flow. Electron flow if measured in amperage so I suppose it is amperage or current that causes the motor to turn.

Some motors are designed to run on dual voltages such as 120/240 volts but each voltage rating will have something called amperage which is used to size the conductors and overcurrent protection.
Have you ever sized a wire based on the voltage for a branch circuit? When calculating the size of a load on a set of feeders do we figure the total voltage? Can I walk in the supply house and tell them I need a 240 volt single phase panel and they lay just what I need on the counter?

Now just what does this motor have to do with the human body?

I am not trying to debate that a current can flow without a voltage being present. I am not trying to debate that the amount of time current flows across a human body does not play a role in the damage done. What I am saying is the same thing that every piece of training material published today says; it is the current (flow of electrons) that travels through the human body that causes the effects not the voltage.

I agree with your statement that electricity can kill but the original question broke this statement down into a smaller statement than this broad statement and ask which part of electricity does the damage and the simple answer to his question is current.

As usual you have tried to carry this discussion off on a tangent and asked about how motors work instead of staying on track of what part of the electricity that does damage to the human body. Let?s try to stay on the subject matter of what does damage to the human body, current or voltage.

Unless you can show me documentation that states that voltage is what does the damage I shall stay with the charts that are published and maintain that it is current or the flow of electrons that causes damage and death to the human body.
I will continue to open my safety classes with your statement of electricity can kill and go on to break it down that it is the flow of electron across and through the human body that does the damage just as those that wrote the text books have stated.
 

pfalcon

Senior Member
Location
Indiana
Body vaporization: Voltage responsible for the dielectric breakdown of the subject.
Body cooked: Current responsible for heating the tissues.
Heart fibrillation: Frequency matched to the heart nervous system.

Different aspects of electricity kill in different ways. To claim it's the current is to limit your view to getting cooked.

Arc Flash: Current melts the components thereby lowering the material's dielectric constant. Voltage causes dielectric breakdown of the compromised copper creating the flash and compression wave. Without sufficient voltage the copper would just gloop to the bottom of the panel.
 

iwire

Moderator
Staff member
Location
Massachusetts

When the first electric motor was patented it patented as a revolving transformer. It is magnetic induction that makes the motor turn.

In order to have magnetic induction there must be electron flow. Electron flow if measured in amperage so I suppose it is amperage or current that causes the motor to turn.

Some motors are designed to run on dual voltages such as 120/240 volts but each voltage rating will have something called amperage which is used to size the conductors and overcurrent protection.
Have you ever sized a wire based on the voltage for a branch circuit? When calculating the size of a load on a set of feeders do we figure the total voltage? Can I walk in the supply house and tell them I need a 240 volt single phase panel and they lay just what I need on the counter?

Now just what does this motor have to do with the human body?

I am not trying to debate that a current can flow without a voltage being present. I am not trying to debate that the amount of time current flows across a human body does not play a role in the damage done. What I am saying is the same thing that every piece of training material published today says; it is the current (flow of electrons) that travels through the human body that causes the effects not the voltage.

I agree with your statement that electricity can kill but the original question broke this statement down into a smaller statement than this broad statement and ask which part of electricity does the damage and the simple answer to his question is current.

As usual you have tried to carry this discussion off on a tangent and asked about how motors work instead of staying on track of what part of the electricity that does damage to the human body. Let’s try to stay on the subject matter of what does damage to the human body, current or voltage.

Unless you can show me documentation that states that voltage is what does the damage I shall stay with the charts that are published and maintain that it is current or the flow of electrons that causes damage and death to the human body.
I will continue to open my safety classes with your statement of electricity can kill and go on to break it down that it is the flow of electron across and through the human body that does the damage just as those that wrote the text books have stated.

Just answer the question Mike it was a simple one, you know I am not going to read all your verbose post.
 
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richxtlc

Senior Member
Location
Tampa Florida
Body vaporization: Voltage responsible for the dielectric breakdown of the subject.
Body cooked: Current responsible for heating the tissues.
Heart fibrillation: Frequency matched to the heart nervous system.

Different aspects of electricity kill in different ways. To claim it's the current is to limit your view to getting cooked.

Arc Flash: Current melts the components thereby lowering the material's dielectric constant. Voltage causes dielectric breakdown of the compromised copper creating the flash and compression wave. Without sufficient voltage the copper would just gloop to the bottom of the panel.

Dielectric Breakdown - when sufficient voltage is applied to cause the electrons of a given material to move (current flow) dielectric breakdown occurs.
Ventricular Fibrillation is caused when the heart muscle is damaged causing the valves to flutter, this may be caused by both AC and DC.
 

pfalcon

Senior Member
Location
Indiana

When the first electric motor was patented it patented as a revolving transformer. It is magnetic induction that makes the motor turn.

In order to have magnetic induction there must be electron flow. Electron flow if measured in amperage so I suppose it is amperage or current that causes the motor to turn.

But since magnetic induction makes the motor work and magnetic field strength can be measured directly we don't have to measure electron flow or define amperage. Therefore current doesn't make the motor turn.

Some motors are designed to run on dual voltages such as 120/240 volts but each voltage rating will have something called amperage which is used to size the conductors and overcurrent protection.
Have you ever sized a wire based on the voltage for a branch circuit? When calculating the size of a load on a set of feeders do we figure the total voltage? Can I walk in the supply house and tell them I need a 240 volt single phase panel and they lay just what I need on the counter?

So, in an industrial plant do you bring in a 100A 250V panel and expect it to survive on my 30A 480V system?

Now just what does this motor have to do with the human body?

I am not trying to debate that a current can flow without a voltage being present. I am not trying to debate that the amount of time current flows across a human body does not play a role in the damage done. What I am saying is the same thing that every piece of training material published today says; it is the current (flow of electrons) that travels through the human body that causes the effects not the voltage.

In fibrillation it's the FREQUENCY that causes the effect, not the current. In an arc flash, it's the VOLTAGE creating dielectric breakdown that creates the damaging effect, not the current. Yes, current is present in both cases, but the primary damage from current is cooking and melting.

I agree with your statement that electricity can kill but the original question broke this statement down into a smaller statement than this broad statement and ask which part of electricity does the damage and the simple answer to his question is current.

The misleading answer is current. The arc from high voltage lines is not driven by current but by the voltage and the dielectric constant of the air. And in all cases sufficient power must be present to enable the damage.
 

pfalcon

Senior Member
Location
Indiana
Dielectric Breakdown - when sufficient voltage is applied to cause the electrons of a given material to move (current flow) dielectric breakdown occurs.
Ventricular Fibrillation is caused when the heart muscle is damaged causing the valves to flutter, this may be caused by both AC and DC.

Poor definition for dielectric breakdown. It occurs when sufficient voltage is applied to cause the ionization of a given material to move the electric charge. As such both negative ionic particles and positive ionic particles migrate, not just electrons. The arc in a dielectric breakdown is not electron migration and therefore is does not fit the classic definition of current. The measurable effective current is dependant on the power available. Current does not need to be present to initiate the event.

Fibrillation does not require damage to the heart. Fibrillation is desynchronization of the heart rhythm. Specific frequencies have greater probabilities of causing fibrillation. DC fibrillation occurs when the heart restarts improperly after being stopped by the DC. Heart damage is a side effect of fibrillation, not the cause.
 

Barndog

Senior Member
Location
Spring Creek Pa
The misleading answer is current. The arc from high voltage lines is not driven by current but by the voltage and the dielectric constant of the air. And in all cases sufficient power must be present to enable the damage.

The Arc is driven from the voltage but it is the current that is moving from on conductor to the other. Its is a combination of things because without voltage you cannot have current. But i do believe that the OP was asking If you complete the electrical circuit what kills you and that would be the flow of electrons through your body (electrical current). there are alot of other ways to die working with and around electricity which include flash burn,
 

pfalcon

Senior Member
Location
Indiana
The Arc is driven from the voltage but it is the current that is moving from on conductor to the other. Its is a combination of things because without voltage you cannot have current. But i do believe that the OP was asking If you complete the electrical circuit what kills you and that would be the flow of electrons through your body (electrical current). there are alot of other ways to die working with and around electricity which include flash burn,

The leading question was whether CURRENT kills versus some other property of electricity. We know they're all present. We all know each property has a part to play. The presumption is based on the concept that after a minimal voltage requirement that the damage scales with current. That presumption is incorrect for most forms of death by electricity.

Dielectric breakdown of the human body is VOLTAGE driven and POWER limited. Current is a side effect created by the voltage.
Cooking is POWER driven with CURRENT the primary carrier. Voltage is necessary to a limited level for initiation.
Fibrillation is FREQUENCY driven. POWER is necessary to a limited level. Current and voltage are side effects of the power required.
Arc Flash is VOLTAGE driven and power limited. Current is necessary to a limited level for initiation.

So to claim that current kills when the most common form of death is frequency driven fibrillation is absurd. Current kills by delivering power in the form of heat but requires time on the circuit. Frequency kills more often because of the almost instantaneous effect of disrupting the heart rhythm. Fibrillation is almost current independent.
 
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