The Killer - Amps or Volts?

[rlitman]

The simple answer is to shut the power off (and make sure it's off) before working on anything electrical.

I'll remember that when I'm working with capacitors and batteries.

All this time I thought submarines were cordless.

Ha. While I was actually talking about submarine power transmission, there are plenty of corded submarines out there too. Probably as many as or more than cordless. Tethered ROVs are used for all sorts of things. Though I couldn't say whether their power is AC or DC.

 

[ddawg16]

So he came and went at the same time, huh?

Pretty much.......I believe it was the seminal fluid on the erect member which caused an increase in conductivity, i.e., more current flow, coupled with the spasms which prevented the guy from being able to pull the plug out of the wall, and thus lead to his demise.

Cooked hot dog takes on a whole new meaning

 

[Stuart in MN]

I'll remember that when I'm working with capacitors and batteries.

The original poster never said anything about capacitors or batteries, but you should discharge the capacitors before working with them and keep your tongue off the battery terminals.

 

[Brian_WK]

Pretty much.......I believe it was the seminal fluid on the erect member which caused an increase in conductivity, i.e., more current flow, coupled with the spasms which prevented the guy from being able to pull the plug out of the wall, and thus lead to his demise.

Cooked hot dog takes on a whole new meaning

 

[D45]

Considering a tazer hits you with a boatload of voltage, but only a few milliamps.

Its 50k at the device...........around 5k by the time the probes hit

The amps are extremely low

It works on neuromuscular incapacitation............not paint compliance

Basically jams signals and communications sent from the brain to the muscles

If the muscles don't known what to do, they lock up

 

[TractorJeff]

Fun Thread to read!
For What Its Worth;
Been told that in Europe, extremely high voltage long distance transmission lines are DC.
It reduces the capacitance generated between the lines which increases efficiency of transmission.

 

[ard]

Basically jams signals and communications sent from the brain to the muscles

If the muscles don't known what to do, they lock up

Not exactly correct. The shock actually cause the muscular contractions, its not that 'muscles get confused so they lock'.

And as you allude, there are different modes/voltages/frequency- with pain compliance the goal with some ....

 

[DC73]

Those who said the killer is amps are correct. A good analogy for an electrical distribution system is a water distribution system. Voltage equates to pressure in the water system. It pushes the current through the wires and through the load. But, it's the resistance of the load that determines how much current actually flows. And, in the case of electricity flowing through the human body, the path the electricity takes is also important. Electrical workers who come into contact with high voltage electricity live to tell about it far more often than not.

I spent over 5 years monitoring monthly electrical safety meetings. Each meeting started by reviewing an accident that occurred somewhere in the U.S. (most were electrical contact accidents). Electrical contact occurred at all voltages including 120, 240, 480, 600, 2400, 7200 and higher. There were some nasty injuries including loss of fingers and hands but relatively few deaths. The deaths that did occur were generally attributed to excess current (amps) flowing through the heart or to falls from poles or buckets after contact occurred. None of the deaths were attributed to voltage.

You can live after coming into contact with high voltage but as discussed by others in this thread, even small amounts of current can put you in the ground.

Work safely folks.

DC

 

[Copymutt]

Glad that's solved,
now grab a big pickle, stab a couple nails in it length wise, one each end.
Leave an inch or so between the nail points. connect an AC 2 wire feed, one to each nail. Douse the lights and plug er in.
It's alive!
Not responsible for overcooked veggies or humans.
Jim

 

[Matt Matt]

Those who said the killer is amps are correct. A good analogy for an electrical distribution system is a water distribution system. Voltage equates to pressure in the water system. It pushes the current through the wires and through the load. But, it's the resistance of the load that determines how much current actually flows. And, in the case of electricity flowing through the human body, the path the electricity takes is also important. Electrical workers who come into contact with high voltage electricity live to tell about it far more often than not.

I spent over 5 years monitoring monthly electrical safety meetings. Each meeting started by reviewing an accident that occurred somewhere in the U.S. (most were electrical contact accidents). Electrical contact occurred at all voltages including 120, 240, 480, 600, 2400, 7200 and higher. There were some nasty injuries including loss of fingers and hands but relatively few deaths. The deaths that did occur were generally attributed to excess current (amps) flowing through the heart or to falls from poles or buckets after contact occurred. None of the deaths were attributed to voltage.

You can live after coming into contact with high voltage but as discussed by others in this thread, even small amounts of current can put you in the ground.

Work safely folks.

DC

Head to toe (toe being grounded) what would you prefer?

120 V AC at 15 A ...or
1800 V AC at 1 A???

I have been hit by one, I don’t want to be hit by the other.

Edit, Most mosquito rackets have a voltage 900 to 2000 v. The amperage and proximity jump is only designed to fry mosquitoes or bugs.but,... About six of these put together is a taser.

 

[driftpin]

FYI, the source of current in a hospital's or paramedic's defibrillator is a handful of C-cell batteries, if you opened one of the removable battery packs, last one I saw.

In cardiac resuscitations using external defibrillators, the maximum voltage dispensed is 400 joules; 1 joule=1 watt.

Having to travel through skin layers, and underlying tissue, including muscle, to reach the heart muscle, takes some energy. If the heart was laid-bare, as-in having the chest cavity open, the amount of energy delivered to the heart to start it beating once-again is much-less than when the chest is intact.

Also, the direction of the current applied is important. Years-ago, the current was transmitted in the USA primarily in one direction (uniphasic) while now the standard is to have it go in two directions, think, "a round-trip." That's "biphasic."

Concerning the use of a cardiac monitor, capable of delivering synchronized (Cardioversion) or unsynchronized (Defibrillation) levels of energy:

All those movies and hospital TV shows with the doctors using the paddles, the standard now is to use lubricated pads in-place of the paddles. This is safer for the team and often allows better results for the patient.

The defibrillator fires when the button is pushed. The machine in cardioversion mode will sense the underlying cardiac rhythm and will delay the delivery of energy level selected until the correct time in the cardiac energy delivery cycle, which is vitally-important to the success of the delivered shock allowing the heart to start to beat rhythmically once-again. What it's doing is wiping-out the heart's erratic electrical activity which isn't allowing the coordinated flow of blood through the heart, and allowing the correct electrical pathway for energy to travel properly through the heart muscle, resulting in effective cardiac output (pumping action) again.

The Automated External Defibrillator (AED) can sense if there is an electrical rhythm present, but it cannot determine if the heart is producing cardiac output, which is why the AED will inform the user: "Check for pulse." A condition where there is a good rhythm but no cardiac pumping output is called "Pulseless Electrical Activity," (PEA) and is where the hospital or paramedics would be doing chest compressions.

Once the heart goes 'straightline,' (Asystole) there is no shocking to be done. You have to have some type of cardiac electrical activity to work-with. In Asystole, there is none.

The use of external pacemakers is sometimes necessary to get the heart pumping effectively again, and if the patient is conscious, yes, this is very uncomfortable, and the patient is likely to be sedated. Modern EKG defibrillator/cardioversion machines have integral pacemakers. A typical level of delivered energy to keep the heart beating with an effective pumping action while using an external pacemaker is probably in the 70-110 joule range, assuming an adult patient.

I would rather be subjected to volts than amps.

When Thomas Edison was trying to convince the country to use DC instead of Nikolai Tesla's discovery of AC, he would electrocute farm animals with AC to show "how-dangerous" it was.

 

[Matt Matt]

FYI, the source of current in a hospital's or paramedic's defibrillator is a handful of C-cell batteries, if you opened one of the removable battery packs, last one I saw.

In cardiac resuscitations using external defibrillators, the maximum voltage dispensed is 400 joules; 1 joule=1 watt.

Having to travel through skin layers, and underlying tissue, including muscle, to reach the heart muscle, takes some energy. If the heart was laid-bare, as-in having the chest cavity open, the amount of energy delivered to the heart to start it beating once-again is much-less than when the chest is intact.

Also, the direction of the current applied is important. Years-ago, the current was transmitted in the USA primarily in one direction (uniphasic) while now the standard is to have it go in two directions, think, "a round-trip." That's "biphasic."

Concerning the use of a cardiac monitor, capable of delivering synchronized (Cardioversion) or unsynchronized (Defibrillation) levels of energy:

All those movies and hospital TV shows with the doctors using the paddles, the standard now is to use lubricated pads in-place of the paddles. This is safer for the team and often allows better results for the patient.

The defibrillator fires when the button is pushed. The machine in cardioversion mode will sense the underlying cardiac rhythm and will delay the delivery of energy level selected until the correct time in the cardiac energy delivery cycle, which is vitally-important to the success of the delivered shock allowing the heart to start to beat rhythmically once-again. What it's doing is wiping-out the heart's erratic electrical activity which isn't allowing the coordinated flow of blood through the heart, and allowing the correct electrical pathway for energy to travel properly through the heart muscle, resulting in effective cardiac output (pumping action) again.

The Automated External Defibrillator (AED) can sense if there is an electrical rhythm present, but it cannot determine if the heart is producing cardiac output, which is why the AED will inform the user: "Check for pulse." A condition where there is a good rhythm but no cardiac pumping output is called "Pulseless Electrical Activity," (PEA) and is where the hospital or paramedics would be doing chest compressions.

Once the heart goes 'straightline,' (Asystole) there is no shocking to be done. You have to have some type of cardiac electrical activity to work-with. In Asystole, there is none.

The use of external pacemakers is sometimes necessary to get the heart pumping effectively again, and if the patient is conscious, yes, this is very uncomfortable, and the patient is likely to be sedated. Modern EKG defibrillator/cardioversion machines have integral pacemakers. A typical level of delivered energy to keep the heart beating with an effective pumping action while using an external pacemaker is probably in the 70-110 joule range, assuming an adult patient.

I would rather be subjected to volts than amps.

When Thomas Edison was trying to convince the country to use DC instead of Nikolai Tesla's discovery of AC, he would electrocute farm animals with AC to show "how-dangerous" it was.

Massive capacitors are involved.... this is why there is a charge time. Both amps and volts need to be present for an effective surge.

 

[rlitman]

...In cardiac resuscitations using external defibrillators, the maximum voltage dispensed is 400 joules; 1 joule=1 watt.
...

NO.

Watts are units of power.
Joules are units of energy.
And voltage is irrelevant.

1 joule = 1 watt second.
So, 400 joules = 400 watts for a period of 1 second.

But a defibrillator pulse could be shorter than 1 millisecond, so the wattage of a 400 J pulse that only lasts 1 ms would be a thousand times greater.

So, a 1 ms pulse that has 400 J of energy would be 400 kW!

Now to be fair, it seems that many pulses may be 10x as long, so that's only 40kW of output, but still, that's a crazy amount of power to be shocked with.

 

[McFarmer]

When I taught welding to eighth graders I told them the mig welder is like a garden hose. Voltage is the size of hose, amps is the pressure behind it.

I could be wrong, I'm sure.

 

[bczygan]

Pretty much.......I believe it was the seminal fluid on the erect member which caused an increase in conductivity, i.e., more current flow, coupled with the spasms which prevented the guy from being able to pull the plug out of the wall, and thus lead to his demise.

Cooked hot dog takes on a whole new meaning

Mmmmmmmm! Cooked hot dogs!

Your sentence flooded my brain, with a taste memory of a juicy sizzling beef hot dog!

Think I'll go have one!

Bill

 

[Trey T]

When I taught welding to eighth graders I told them the mig welder is like a garden hose. Voltage is the size of hose, amps is the pressure behind it.

I could be wrong, I'm sure.

From K-12 and older, most ppl have been taught that amp kills but that's assuming that the voltage (and frequency) is constant. That's not the fundamental of electricity when being applied to human body; therefore, many ppl were taught with a general sense in mind and inaccurate.

The thread is getting awfully disorganized as-is but in order to understand the intent of the OP, we have to break it down the term "kill". To kill someone with electricity, you have to imagine the human body in-place of a circuit: cut a section of the live-wire and put a human body in between it. When you imagine this, you think about sizing wires for branch circuit. How do you want to "kill" that body instantly (short duration) - shock/defibrilatte or burn?

1. shock - increase voltage
3. burn - increase amp

There are depths to the topic such as frequency, resistance, etc....

 

[exmaxima1]

Nikola Tesla used to amaze people by lighting up fluorescents in his hand and absorbing tens of thousands of high frequency AC volts and passing them on to ground. No amperage.
Jim

Like this

 

[bullnerd]

All I know is when your like 10 and you hold the spark plug wire on your minibike, and push down on the kick starter.....it feels really neat!

 

[dogdog]

From K-12 and older, most ppl have been taught that amp kills but that's assuming that the voltage (and frequency) is constant. That's not the fundamental of electricity when being applied to human body; therefore, many ppl were taught with a general sense in mind and inaccurate.

The thread is getting awfully disorganized as-is but in order to understand the intent of the OP, we have to break it down the term "kill". To kill someone with electricity, you have to imagine the human body in-place of a circuit: cut a section of the live-wire and put a human body in between it. When you imagine this, you think about sizing wires for branch circuit. How do you want to "kill" that body instantly (short duration) - shock/defibrilatte or burn?

1. shock - increase voltage
3. burn - increase amp

There are depths to the topic such as frequency, resistance, etc....

^^^
This. You'll needed both to kill you.... I think there is a chart on this.

As demonstrated by this video, "2 years" ago I think they have already explained it better.




This

and this

 

[exmaxima1]

The magnetizer I use to activate speaker magnets is essentially a bank of capacitors that can be charged to upwards of 800 vdc. I keep my free arm (and wristwatch) behind my back when I push the trigger. In an instant, the cables jump and thousands of amperes energize a coil. As they say on Forged in Fire, "IT WILL KILL"

 

[bullnerd]

My dad was a tv repair man.(not kidding) I use to sit on his bench and watch him fix countless tvs. Ive been "bit" as he would call it, by the high voltage fly lead or flyback whatever its called on the old tube sets, more times than I can remember and I turned out fine!

What were we talking about?

 

[byoungblood]

Both can kill you but you need a certain amount of voltage to actually travel through your body.

As for the safety of the grinder example. The maximum amount of wattage that will be supplied to the tool is determined by the breaker. 120v 15A = 240V 7.5A (I have no idea what breakers in the 240V 50HZ realm are rated at). So to answer your question on the grinder the 240v has more potential but the rated amp draw of the tool has nothing to do with it.

FYI attached is a picture of me holding 2 meter leads at my desk for how much resistance is from fingertip to fingertip one in each hand.

Brian

I have read that's actually not a very accurate measurement of your body resistance because your typical DVOM uses so little voltage to measure resistance these days. An analog meter may actually give a more accurate reading because they used several volts to measure resistance depending on the measurement scale being used. For example, my Simpson 260 uses 1.5v from a single C battery for the 1-1000x resistance scales, and a 9v battery for the 10,000x scale.

Whatever the actual resistance is, the greater the volts, the greater the current that will flow. However, there must be a return path for the current, so under some circumstances (don't try this at home!) you may not actually be a return path for the current, and won't receive a shock. That's the principle behind using isolation transformers when working on mains powered electronics. By electrically isolating the device under test from the mains, where the neutral (ie., the return path) is physically bonded to the ground in the breaker panel, you remove the return path to earth ground. Unless you touch a hot lead AND something that is connected to the neutral of the isolation transformer at the same time, you shouldn't receive a shock; there is nowhere for the current to go to. Generally it is recommended to keep one hand behind your back or in a pocket if you have to probe an energized high voltage circuit to avoid such a possibility.

FWIW, the actual amount of current passing through your body depends on your actual resistance and the resistance of whatever you are in contact with. So saying "would you rather be shocked by 30v at 15A or 1000V at .5A" is incorrect. If your body resistance is 10k ohm, then at 30V you'd draw 3mA (.003A) and at 1000V, 100mA (.1A).

 

[alfredeneuman]

When I taught welding to eighth graders I told them the mig welder is like a garden hose. Voltage is the size of hose, amps is the pressure behind it.

I could be wrong, I'm sure.

The exact opposite is true. Amps is the size of the hose, and voltage is the pressure.

 

[exranger06]

Head to toe (toe being grounded) what would you prefer?

120 V AC at 15 A ...or
1800 V AC at 1 A???

I have been hit by one, I don’t want to be hit by the other.

Doesn't matter, you'd be dead if you got hit by either. I'm assuming you got hit at 120v. You definitely did not have 15A going through you, because you wouldn't live to post about it. And how would you know that you had 15A going through you? Again, just because a circuit has a 15A breaker does NOT mean that you'll have 15A going through you if you touch it. If you plugged in a 100w light bulb into a 15A circuit, and there's nothing else on the circuit, does that mean there's always 15A going through the wires? NO. 100w divided by 120v = 0.83 amps going through the bulb and the wires. Now substitute your body for the light bulb. The amount of current going through you is entirely dependent on your body's resistance and the voltage. The breaker size has NOTHING to do with it. If your body has say, 10,000 ohms of resistance, then 120v divided by 10,000 = 0.012 amps, or 12mA. Not 15A.

There's a reason why GFCIs exist, and there's a reason they trip with as little as 5mA imbalance. If you're waiting for the current to go over 15A so the breaker will trip, you're already a toasted marshmallow.

 

[Matt Matt]

Here is the silly video explanation again.

 

[exranger06]

Yeah that guy basic said exactly what I said at about 1:36 in the video. He explained how the current through his tongue depends on the resistance of his tongue and the voltage. Nothing else. I have a bachelor's degree in electrical engineering, so I'm quite familiar with Ohm's Law already.

 

[rlitman]

Yeah that guy basic said exactly what I said at about 1:36 in the video. He explained how the current through his tongue depends on the resistance of his tongue and the voltage. Nothing else. I have a bachelor's degree in electrical engineering, so I'm quite familiar with Ohm's Law already.

I don't think he was disagreeing with you, just adding some levity to the conversation.

 

[aka Larry]

Once the heart goes 'straightline,' (Asystole) there is no shocking to be done. You have to have some type of cardiac electrical activity to work-with. In Asystole, there is none.

My wife is an RN and she gets riled up anytime a TV or movie shows someone shocking asytole!

 

[Mr. T]

I think an important thing missing is that the volt is a derived unit. It can only be quantified by a comparison of two things. The Ampere is a base unit (measurement of a real thing). So it’s the real thing that will kill a real person, not a comparison.

The amps are what actually do work. This is way too simplistic but also true.

 

[driftpin]

I think the shows often use a medical consultant to gain credibility, but it's still fun to catch the errors.

My wife is an RN and she gets riled up anytime a TV or movie shows someone shocking asytole!

 

[Brian_WK]

My wife is an RN and she gets riled up anytime a TV or movie shows someone shocking asytole!

She probably says the same thing when you see a car in a movie do a wheelie on sand at 190mph...

Brian

 

[dave*99]

She probably says the same thing when you see a car in a movie do a wheelie on sand at 190mph...

Brian

Or hears tires screeching and squealing on sand.

 

[C.L S2000]

LOL this one actually is really good...@50 sec

hilarious

 

[fabjunkie]

She probably says the same thing when you see a car in a movie do a wheelie on sand at 190mph...

Brian

Or hears tires screeching and squealing on sand.

Or the pump on a car lift running as they're lowering it.

 

[LS6 Tommy]

When I taught welding to eighth graders I told them the mig welder is like a garden hose. Voltage is the size of hose, amps is the pressure behind it.

I could be wrong, I'm sure.

You, in fact, have it almost 100% backwards...

When using the "Garden Hose" analogy,

Voltage is perceived as pressure.
Amperage is perceived as volume of flow.
Resistance is perceived as pipe size.

Tommy

 

[marinusdees]

Fun Thread to read!
For What Its Worth;
Been told that in Europe, extremely high voltage long distance transmission lines are DC.
It reduces the capacitance generated between the lines which increases efficiency of transmission.

Also, in the US. The problem is that at some maximum voltage, something called the "skin effect" kicks in, resisting further voltage increases. Not so with DC. There has to be some limiting factor with DC, but I don't know what that is.

 

[laser3kw]

Also, in the US. The problem is that at some maximum voltage, something called the "skin effect" kicks in, resisting further voltage increases. Not so with DC. There has to be some limiting factor with DC, but I don't know what that is.

Most will never experience a "RF" burn (radio frequency)

 

[rlitman]

Also, in the US. The problem is that at some maximum voltage, something called the "skin effect" kicks in, resisting further voltage increases. Not so with DC. There has to be some limiting factor with DC, but I don't know what that is.

The skin effect has nothing to do with voltage. It is related to frequency. As frequency increases, the depth at which the current flows is reduced. The net effect is that above a certain frequency, current may not be making use of the center of a large conductor. However, at 60hz, you will not see much of this effect in wires smaller than 500 mcm. But because of this, at 60hz, as you increase wire diameter past around 16.8mm, the ampacity starts to increase with the circumference of the wire, as opposed to the cross sectional area. And this is why you will often see two 350 mcm wires run in parallel, instead of a single 700 mcm wire (as an example).

There is no skin effect with steady state DC. Though DC transmission lines are not necessarily operating at a constant voltage.