What would be an intelligent responce?
- Thread starter Hendrix
- Start date
- Status
Ahhh - now we're getting somewhere - lack of air, caused by a combination of fabric and adhesive.
db
jwelectric
Senior Member
- Location
- North Carolina
Not having a PHD nor even know how to sling the BS but one thing I do know is that there can be no electrical power without the flow of CURRENT.
I also know that the FREQUENCY is the rate of change of the CURRENT.
Ions both have a positive or negative charge and will aid the flow of CURRENT
An arc flash has heat and you made the statement that current is heat therefor the flash has CURRENT.
Maybe you should rewrite all the safety manuals and charts that have been around for years that clearly state that it is the current that does damage.
I will continue to use that which is printed by my government (OSHA) which states that it is current that does damage. Me and my dumbed down government stand pat; it is the current that does the damage.
- Location
- Simi Valley, CA
Barndog
Senior Member
- Location
- Spring Creek Pa
Yes i have heard this as well.
- Occupation
- Licensed Electrician
I won't argue, but hot metal does it quicker.
And while it is a quite silly example the truth remains that there was a lot of current present during my home medical procedure and I was never in fear for my life.
jwelectric
Senior Member
- Location
- North Carolina
But there was not even one electron that passed through your body. they all passed through the iron
Why you would want to sling that stuff I really don't know
And hopefully by now we can stop regressing to claims that someone denied the existence of current. Never happened. We are debating its significance.
Current is not heat. Current provides delivery of power. Power provides the energy to melt the copper. The energy is heat.
Which is all irrelevant because 10MA of current will cause melt but will not create the Arc Flash if there isn't enough voltage to provide dielectric breakdown. All you'll get is some melted copper and a cut circuit. Which is how a fuse works in the first place.
Actually, most of those charts presume that voltage is a constant and that current is being controlled. But feel free to check your charts again such as SCCR ratings. You'll see that they take voltage seriously, because in the end it's the amount of power delivered. And for a given amount of power, voltage and current are inversely proportional.
And why would you change? Current is what is easiest to control. Current control should be taught.
The simplest best answer to the OP is still: "Who is your next of kin?"
- Location
- Massachusetts
I have already, but to replay it ...
If it was all about the current and nothing else we would both be dead already.
jwelectric
Senior Member
- Location
- North Carolina
You are trying your best to bring physics into a simple problem.
We both know that power can?t exist unless there is current. We both know that voltages or dielectric breakdown if you wish is nothing more than the amount of pressure it takes to push the current through the resistance.
We both know that current is what moves and delivers the power or energy to the load but we both know that energy does not necessarily mean that voltage or current is present. A blown out tire releases energy without voltage or current.
Voltage does not move, power is the result of voltage and current. Electrons move and the movement of the electrons is measured in amperage or current.
Call it dumbing it down or whatever you want to call it but the basic answer to the original of which kills voltage or current the answer is current.
I shall not waste any more energy (no voltage or current in use in this energy) responding any future.
- Location
- Simi Valley, CA
I actually used this thread for training last week.
I told my guys plain and simple (as I said earlier) dead is dead, it doesn't really matter how you got that way, your family won't really care if it was the voltage or the amps. BE CAREFUL!
I told my guys plain and simple (as I said earlier) dead is dead, it doesn't really matter how you got that way, your family won't really care if it was the voltage or the amps. BE CAREFUL!
- Location
- Massachusetts
So now we all understand it is more than just current that kills.
Great, glad you where able to see things clearly now.
That is an opinion, it carries as much or as little weight as my opinion or anyone's and IMO you are mistaken.
K8MHZ
Senior Member
- Occupation
- Electrician
High Voltage
by Mark Derby (Done in the voice of Henry Gibson)
High voltage
will not kill
A bird on a wire
But I squared R
Will set your house on fire.
In a car is thirty
mighty thousand volts
I've tickled many plug wires
and have gotten many jolts.
But in a house one-twenty
has managed many kills
using only amperes
of a couple hundred mills.
(Dedicated to Bob)
Copyright 2011
Mark Derby
Poet Laureate of Wolf Lake, Michigan
by Mark Derby (Done in the voice of Henry Gibson)
High voltage
will not kill
A bird on a wire
But I squared R
Will set your house on fire.
In a car is thirty
mighty thousand volts
I've tickled many plug wires
and have gotten many jolts.
But in a house one-twenty
has managed many kills
using only amperes
of a couple hundred mills.
(Dedicated to Bob)
Copyright 2011
Mark Derby
Poet Laureate of Wolf Lake, Michigan
Last edited:
Ah, now I see the error of my ways. The physics is contradicting the simple solution. :weeping:
jwelectric
Senior Member
- Location
- North Carolina
You are trying to use the physics of current flow to prove something that most can?t understand.
You say that it is energy that causes the ill effects of current flow. Energy is how much power that is being consumed over a certain amount of time. Energy in most cases is measured in joules. One joule is the amount of energy that is needed to move one pound nine inches in one second. One joule per second equals one watt of power.
When I get on my treadmill for one hour I will expend about 1000 joules of energy and it does not constitute death so to say that energy causes death is false.
Ohm?s Law has four components, Power or watts, voltage, current or amps, and resistance.
Current is the movement of electrons. Current is what that moves through the circuit.
Current or the movement of electrons through muscle tissue of the human body causes the muscle to contract. When current moves across the heart muscle it causes the muscle to contract into a tight ball and when released can cause fibrillation and death. It is current that causes injury or death. It is the flow of electrons through the human body that causes the ill effects plain and simple.
It doesn?t matter if you believe it or not it does not change the laws of physics that you are trying to use to prove your point.
Printed by Cutnell, John D., Johnson, Kenneth W. Physics. 4th ed. New York, NY: Wiley, 1998.
?Currents of approximately 0.2 A are potentially fatal, because they can make the heart fibrillate, or beat in an uncontrolled manner."
Notice there is no mention of voltage or frequency.
Printed by Watson, George University of Delaware. March 8, 1999.
"0.10 amps death due to fibrillation 0.20 amps no fibrillation, but severe burning, no breathing"
Again no mention of voltage or amount of energy
Printed by Zitzewitz, Paul W., Neff, Robert F. Merrill Physics, Principles and Problems. New York: Glencoe McGraw-Hill, 1995 (McGraw-Hill is one of the text books I use)
"The damage caused by electric shock depends on the current flowing through the body -- 1 mA can be felt; 5 mA is painful. Above 15 mA, a person loses muscle control, and 70 mA can be fatal."
What about the voltage and frequency or the amount of energy? Did you forget about all these things?
I can?t help but wonder why all these experts disagree with the notion that voltage or energy does the harm but all agree that the amount of current causes the ill effects. Maybe it is because they just don?t understand physics or have the wrong opinion. At any rate I think I will stay with their opinions as they seem to be a lot smarter than I am.
That may be, but most not understanding the physics won't make most right. A vacuum doesn't suck, it's the pressure that blows.
Close enough, the ENERGY at certain POWER levels, and the FREQUENCY at other POWER levels.
So how come the current going through the motor on your treadmill doesn't cause death? Why isn't the current passing through your nervous system to control your muscles not causing death? No amount of current, energy, power, or frequency will cause death if it's not in a vital spot in sufficient magnitude.
Current is a velocity measurement of energy. Current doesn't move through anything. Electrons do. Ions do.
Re: Fibrillation: Consider the Bose noise canceling headphone. Virtually no power or current but by matching frequency response it eliminates noise. Fibrillation works the same way. The better the frequency match to the muscles, the more likely the heart rhythm can be disrupted. High current/energy is not required. Just helpful like white noise to mask the rhythm.
Wow! They're generating a current without voltage! Bet it's in the text defining the experiments being performed.
Forget? :jawdrop: I'm the one saying they count!
Hmm, no where did you quote that they disagree with voltage/energy causing harm. Hmm, maybe cause they never said it. Maybe because they selected a voltage to work with. Maybe because once you have a voltage, and a resistance, Energy and Power are easiest to imply by measuring current and time.
I don't have those books to pull out. I've read plenty though. They typically select 120VAC @ 60hz to test against here in the US. In the experiment set up they state explicitly that they use that setup because it's the most likely for the typical person to be exposed to. Most often they then state that at different voltages and frequencies that the current values will change.
jwelectric
Senior Member
- Location
- North Carolina
The voltage can be 25 to 25,000 AC or DC, line voltage or communication line. One can be in contact with the circuit from one nanosecond to all day. But the one thing that remains constant is the amperage. AT 100 milliamps death can occur at any voltage or frequency.
A single pole 120 volt GFCI breaker opens at 4 to 6 milliamps
A Double pole 240 amp GFCI breaker opens at 4 to 6 milliamps
What changed? Was it the frequency? Was it the voltage? Was it the amperage? Why?
I suppose that UL hasn?t yet learned that the GFCI device should open at different amperages when the voltage or frequency changes, oh well??????????
Actually, At or above 50Vac and 100mA, death is likely to occur from fibrillation. Increasing the current does not change the probability but changing the frequency does.
At 50Vac and over 200mA we can stop worrying about fibrillation and wonder which vital organ is getting cooked. The heart is no longer the only target.
Since on these devices we have a defined frequency and a defined voltage, what did you expect the third rating to be? Excessive energy loss = chance of death. Last I checked the GFCI actually operated by magnetic induction. Which relates to current but isn't. So by your rationale, magnetic induction kills people.
So, were you planning to use that US household GFCI overseas? UL requires the construction of a GFCI to be changed for overseas voltages but holds the current constant. So by your measure, voltage kills.
You'll find that UL forces all the ratings to be based on the highest voltage the device is expected to handle based on application. So some devices have multiple voltages listed and thereby list different current draws for each voltage to be used in different applications.
- Status