Man grabs high voltage wire while on top of train..... does not end well

[Vic]

Originally posted by: LordMorpheus

Originally posted by: Sea Moose
Lets put this into perspective.

240v supply with a kettle with a resistance of say 26ohms

ohms law = V/R=I

Therfore 240volts/26ohms = 9amps


The man in the video.

The human body has a resistance of about 50,000 ohms(this varies from person to person)
The voltage on the site says the main line voltage is either 1.5kv DC or 25kV AC.

We can calculate both figures using ohms law.

1 500volts/50 000ohms = .3amps <--- Thats right, less than one amp.

25 000volts/50 000 = .5amps <--- Also less that one amp.



The interesting thing is his power output

When charcol gary is drawing .3amp his power output is 45watts <--- Comparable to a light globe
When charcol gary is drawing .5amp his power output is 12500watts <--- comparable to an air conditioning unit for a small house.

Take this into account

.001amps to 0.01 = threshold of sensation
.01amp to .1amp = painful shock, cannot let go, muscular paralysis, severe shock, breathing difficultys
0.1amps to 0.2 amps = death
0.2amps to 1.0amp = severe burning.




May i remind all to be careful around electricity please. may i also point out that his arms go rigid.

Assuming his skin was wet due to sweat, you're looking at closer to 3000 Ohms.

So say half an amp of current dissipating 750 Watts of power.

For the system to detect a fault severe enough for it to cycle like that, maybe there is something else at work here? Surely the train draws on the order of several hundred kW to run, so how would half an amp trip the system?

Because it was WAAAYYY past 'severe burning.'

1 horsepower = 746 watts. How many hp do you think it takes to move those trains?

 

[Special K]

Originally posted by: lyssword
When I was a child I grabbed small electric water heater (220volts) and the electricity made my muscles rigid I couldnt get it off for like 5 seconds I had to pry it off with my other hand.

In that case, wouldn't your free hand just turn into another conductor as soon as you grabbed the stuck hand? They would effectively be connected in parallel.

 

[idiotekniQues]

it's like the same effect as megan fox riding me like a choo choo train

 

[xanis]

Originally posted by: idiotekniQues
it's like the same effect as megan fox riding me like a choo choo train

Except that this is a lot more realistic.

 

[SonnyDaze]

Originally posted by: hiromizu
I take it he's not quite OK

Before or after? :laugh:

 

[NL5]

Originally posted by: MrDudeMan

Originally posted by: SlowSpyder

Originally posted by: zoiks
So I suppose the current passing through charcoal gary didn't have enough oomph to zap any of the people touching the train?

I'm no expert, but I'm pretty sure electric always takes the path of least resistance. So, the voltage going through the train will just go down through the wheels into the track... probably how it's designed. I don't think it would go through someone touching the train and through them into the ground.

It would go through someone touching the train if they were standing barefoot on dirt, but the majority of the current would still go through the axles/wheels into the track and then into the ground via the nails/spikes holding them down. Any type of shoe or material separating a train-touching-onlooker would present a huge series resistance to any current headed their way and drastically reduce the amount they would be exposed to unless they were standing in a puddle.

Anytime there is a difference in potential, current will flow. If the train has a high potential, and the ground is 0, you'd get shocked. How much depends on the total current and your resistance.

 

[NL5]

Originally posted by: MrDudeMan


Also, the body isn't an ohmic material. After the first bit of current started shocking him, his resistance changed and even more current was drawn. It's similar to how a lightbulb draws thousands of amps and quickly is reduced to something manageable after the resistance of the filament changes due to heat. I wouldn't be surprised if hundreds or thousands of amps were going through him before the fault protection stopped it. Burned or blistered skin has basically negligible resistance and it only takes a few microseconds for that to happen. The current was hitting him for at least a few hundred milliseconds, well beyond what would be necessary to blister his enter body. He was basically a short to ground after that point.

Yep. And it also depends on where the train was located in the circuit. The farther out on a line, the more current can go to ground w/o tripping a relay. It sure appeared that the relay tripped the breaker though, and the recloser closed it for a second jolt. Probably reclosed a second time since the fault had cleared......

 

[Mark R]

Dramatic illustration of why high voltage is dangerous.

Overhead train power lines are typically 25 kV AC - this is fairly universal around teh world, with lower voltages (typically 0.7 - 1.5 kV DC also used). The buzzing confirms that this was AC, and the size of the arc is consistent with 25 kV.

It's slightly interesting why the guy got zapped twice - most likely, it was one arm brushed the cable striking the first arc, and then fell away, and then the other struck another arc. It's very unlikely that this was a fault causing a circuit breaker to open and re-close. For a start, this incident would not have registered as a fault condition on the line - trains draw power from the hot line, and use a ground return (no way you can use a protective device like a GFI in a circuit like that), and the current flowing through him is likely to be fairly small compared to the power consumption of a train. Trains can take 500 A during acceleration.

You can see the amount of energy dissipated, because his body is on fire at the end. You can estimate the power flow by estimating the resistance of the human body (approximately 100 Ohms - at the voltages in question, the skin resistance and resistance of clothing, etc. can be ignored as they do not offer significant barriers against the high voltage). So at 25 kV, this works out at about 6000 kW (250 A, which is less than the normal current for a train) - again, this is in the right ball park as in 2 seconds this would dissipate enough energy to raise the body temperature by about 50 C - which due to uneven heating, concentrated in bones, skin and clothing, would be consistent with the ignition of clothing and charring of skin.

 

[Sea Moose]

Originally posted by: MrDudeMan

Originally posted by: Quintox

Originally posted by: Sea Moose
Lets put this into perspective.

240v supply with a kettle with a resistance of say 26ohms

ohms law = V/R=I

Therfore 240volts/26ohms = 9amps


The man in the video.

The human body has a resistance of about 50,000 ohms(this varies from person to person)
The voltage on the site says the main line voltage is either 1.5kv DC or 25kV AC.

We can calculate both figures using ohms law.

1 500volts/50 000ohms = .3amps <--- Thats right, less than one amp.

25 000volts/50 000 = .5amps <--- Also less that one amp.



The interesting thing is his power output

When charcol gary is drawing .3amp his power output is 45watts <--- Comparable to a light globe
When charcol gary is drawing .5amp his power output is 12500watts <--- comparable to an air conditioning unit for a small house.

Take this into account

.001amps to 0.01 = threshold of sensation
.01amp to .1amp = painful shock, cannot let go, muscular paralysis, severe shock, breathing difficultys
0.1amps to 0.2 amps = death
0.2amps to 1.0amp = severe burning.




May i remind all to be careful around electricity please. may i also point out that his arms go rigid.

Rubycon, is that you?

(BTW I blanked out on her name and spent 10 minutes searching)

This is wrong since he was undoubtedly sweating. Most of the resistance of a human body is the first layer of skin, but with sweat there is a much lower resistance pathway into the blood. At that point, the resistivity is relatively low, e.g. < 10 ohm cm and it is safe to assume it is traveling through his blood as it is either DC or low frequency AC. The total series resistance of the human body at that point would be far, far less than 50,000 ohms. The currents in this video are definitely higher than a few amps.

Also, the body isn't an ohmic material. After the first bit of current started shocking him, his resistance changed and even more current was drawn. It's similar to how a lightbulb draws thousands of amps and quickly is reduced to something manageable after the resistance of the filament changes due to heat. I wouldn't be surprised if hundreds or thousands of amps were going through him before the fault protection stopped it. Burned or blistered skin has basically negligible resistance and it only takes a few microseconds for that to happen. The current was hitting him for at least a few hundred milliseconds, well beyond what would be necessary to blister his enter body. He was basically a short to ground after that point.

Actually ohms law applies to everthing, you can calculate lightning using ohms law. We know the voltage, we can only theorise his resistance, and then the basic ohms law can be applied.

Current = Voltage/Resistance

Also i forgot to mention that the human body can act as a capacitor, cool huh.

I am not sure why there were two flashes, my bro in law in an electrical engineer i will run it past him.

 

[DrPizza]

Originally posted by: Sea Moose
Actually ohms law applies to everthing, you can calculate lightning using ohms law. We know the voltage, we can only theorise his resistance, and then the basic ohms law can be applied.

Current = Voltage/Resistance

Also i forgot to mention that the human body can act as a capacitor, cool huh.

I am not sure why there were two flashes, my bro in law in an electrical engineer i will run it past him.

Yes, I=V/R
However, as he pointed out, R is not a constant in the human body. Once a current is started through the skin, R drops significantly. If the body was ohmic, then I could change the voltage and measure the current. The current would be directly proportional to voltage. For something like a resistor, as long as you kept the temperature constant, if you graphed V vs. I, the slope would be R or 1/R (depending on which axis you put each)

BUT, if you did this experimentally with a human body, you would not see a straight line - maybe at first, but after a certain amount of current, the skin would be burned through & the resistance would drop dramatically. How much does it take to burn through the skin? A simple charged capacitor from a camera flash would be sufficient. (I found this out the hard way.)

 

[alkemyst]

almost looks that after he touched it, it touched the top of his head.

 

[Goosemaster]

Originally posted by: Mark R
Dramatic illustration of why high voltage is dangerous.

Overhead train power lines are typically 25 kV AC - this is fairly universal around teh world, with lower voltages (typically 0.7 - 1.5 kV DC also used). The buzzing confirms that this was AC, and the size of the arc is consistent with 25 kV.

It's slightly interesting why the guy got zapped twice - most likely, it was one arm brushed the cable striking the first arc, and then fell away, and then the other struck another arc. It's very unlikely that this was a fault causing a circuit breaker to open and re-close. For a start, this incident would not have registered as a fault condition on the line - trains draw power from the hot line, and use a ground return (no way you can use a protective device like a GFI in a circuit like that), and the current flowing through him is likely to be fairly small compared to the power consumption of a train. Trains can take 500 A during acceleration.

You can see the amount of energy dissipated, because his body is on fire at the end. You can estimate the power flow by estimating the resistance of the human body (approximately 100 Ohms - at the voltages in question, the skin resistance and resistance of clothing, etc. can be ignored as they do not offer significant barriers against the high voltage). So at 25 kV, this works out at about 6000 kW (250 A, which is less than the normal current for a train) - again, this is in the right ball park as in 2 seconds this would dissipate enough energy to raise the body temperature by about 50 C - which due to uneven heating, concentrated in bones, skin and clothing, would be consistent with the ignition of clothing and charring of skin.

I just started reading this thread and saw the 250A figure. Oh my.

 

[Sea Moose]

Originally posted by: Goosemaster

Originally posted by: Mark R
Dramatic illustration of why high voltage is dangerous.

Overhead train power lines are typically 25 kV AC - this is fairly universal around teh world, with lower voltages (typically 0.7 - 1.5 kV DC also used). The buzzing confirms that this was AC, and the size of the arc is consistent with 25 kV.

It's slightly interesting why the guy got zapped twice - most likely, it was one arm brushed the cable striking the first arc, and then fell away, and then the other struck another arc. It's very unlikely that this was a fault causing a circuit breaker to open and re-close. For a start, this incident would not have registered as a fault condition on the line - trains draw power from the hot line, and use a ground return (no way you can use a protective device like a GFI in a circuit like that), and the current flowing through him is likely to be fairly small compared to the power consumption of a train. Trains can take 500 A during acceleration.

You can see the amount of energy dissipated, because his body is on fire at the end. You can estimate the power flow by estimating the resistance of the human body (approximately 100 Ohms - at the voltages in question, the skin resistance and resistance of clothing, etc. can be ignored as they do not offer significant barriers against the high voltage). So at 25 kV, this works out at about 6000 kW (250 A, which is less than the normal current for a train) - again, this is in the right ball park as in 2 seconds this would dissipate enough energy to raise the body temperature by about 50 C - which due to uneven heating, concentrated in bones, skin and clothing, would be consistent with the ignition of clothing and charring of skin.

I just started reading this thread and saw the 250A figure. Oh my.

I think your figure of 100ohms is way too lowand if 250amps passed through his body he would have exploded. I have seen things overloaded with current and they explode. The guy was only drawing a couple of amps and he was literaly a human light bulb.

He would have survived if his feet were in the air or in a vacum. his body caused a short to earth, and fault current passed through his body. The flash you saw was no different to lightnig.

There is a potential difference between the train and the power lines and the guys body was the conductor. I think its gross his arms go stiff before they have a chance to touch the train.

 

[Wheezer]

I'm in the mood for some s'mores

 

[arcenite]

That's what I call "out in a flash"

 

[z1ggy]

1.5k? IT was prob more than that. I didnt watch the vid or read.. but just for fun I am am replying. Here in the states..most overhead lines you could reach while on a train, if they are distribution lines are either 4.8kv or 13.2kv. So Im gunna say a lot more than 3A cooked this dude. Now if it was a transmission line..Yeah I think you might turn to ash or something. The breakers on those lines are like 200A minimum.

 

[Sea Moose]

Originally posted by: z1ggy
1.5k? IT was prob more than that. I didnt watch the vid or read.. but just for fun I am am replying. Here in the states..most overhead lines you could reach while on a train, if they are distribution lines are either 4.8kv or 13.2kv. So Im gunna say a lot more than 3A cooked this dude. Now if it was a transmission line..Yeah I think you might turn to ash or something. The breakers on those lines are like 200A minimum.

13200volts/3000ohms = 4.4amps

try it out yourself
http://ourworld.compuserve.com...ill_Bowden/ohmslaw.htm

It only takes 30miliamps to stop your heart. Thats .03amps

If you read back i gave the figures on human survival vs current level.

The biggest variable is the resistance of the humans body. It depends on your fat levels, moisture/sweat etc etc

 

[IGBT]

General Information
Fleet Size - 22
Type - Articulated w/3 trucks
Doorways per car - 4 per side
Capacity (Seated) - 70 (approx.)
Capacity (w/Standees) - 155 (approx.)
Capacity (Crush Load) - 250 (approx.)
Features - HVAC, Automated Announcements

Technical Information
Length - 88-94 feet
Width - 8' 8 3/4"
Height - 12' 5"
Interior Headroom - 6' 7"
Interior Floor Height - 14" above top of rail
Weight - 105,000 lbs. empty
Gauge - 4' 8 1/2" (Standard)
Operating Voltage - 750 VDC
Traction Motors - 4 AC motors per car
Traction Controls - AC Drive
Braking - Re-generative-Dynamic/Friction/TrackBrake
Average Acceleration - 3 mphps
Average Deceleration - 3 mphps (Normal) - 5 mphps (Emergency)
Max Speed - 55 mph
Carbody Construction - Corten Steel

 

[feralkid]

Originally posted by: z1ggy
1.5k? IT was prob more than that. I didnt watch the vid or read.. but just for fun I am am replying. Here in the states..most overhead lines you could reach while on a train, if they are distribution lines are either 4.8kv or 13.2kv. So Im gunna say a lot more than 3A cooked this dude. Now if it was a transmission line..Yeah I think you might turn to ash or something. The breakers on those lines are like 200A minimum.

This was the catenary line which provides current to the train itself, not some transmission or distribution line that happened to be within reach of the train.

 

[Sea Moose]

Originally posted by: IGBT
General Information
Fleet Size - 22
Type - Articulated w/3 trucks
Doorways per car - 4 per side
Capacity (Seated) - 70 (approx.)
Capacity (w/Standees) - 155 (approx.)
Capacity (Crush Load) - 250 (approx.)
Features - HVAC, Automated Announcements

Technical Information
Length - 88-94 feet
Width - 8' 8 3/4"
Height - 12' 5"
Interior Headroom - 6' 7"
Interior Floor Height - 14" above top of rail
Weight - 105,000 lbs. empty
Gauge - 4' 8 1/2" (Standard)
<Operating Voltage - 750 VDC
Traction Motors - 4 AC motors per car
Traction Controls - AC Drive
Braking - Re-generative-Dynamic/Friction/TrackBrake
Average Acceleration - 3 mphps
Average Deceleration - 3 mphps (Normal) - 5 mphps (Emergency)
Max Speed - 55 mph
Carbody Construction - Corten Steel

Ok, we can apply ohhms law.

Voltage = 750
Resistance = 500ohms If charcol gary is all hot and sweaty
Resistance = 10,000 if charcol gary is dry


Resistance is a variable, as i mentioned several times it all depends on how sweaty he is body fat etc etc etc

therfore

I=V/R

volts/Resistance=current
750/500= 1.5amp
750/10,000=.075amp

The human body cannot draw 250amps.

http://van.physics.illinois.edu/qa/listing.php?id=6793

 

[DanTMWTMP]

man, i've got to see this when i get back to faster internets later today. so marked!

My roommate had one of those electric ab-exercise things. Those things actually really hurt when you put it full blast on your forearm. You can't control the involuntary contractions going through your arm. Anyways, in an attempt to wake me up from my deep sleep, my roommate put that thing on my forearm, and left it at the highest setting. He told me he couldn't stop laughing because my arm was flopping all over the place, and I was still sound asleep.

 

[alkemyst]

Most really underestimate electricity. I have had a few close calls, one had me feeling really off for months.

This is an interesting read:http://www.physics.ohio-state....ety/fatal_current.html

 

[alkemyst]

Originally posted by: Sea Moose

Originally posted by: IGBT
General Information
Fleet Size - 22
Type - Articulated w/3 trucks
Doorways per car - 4 per side
Capacity (Seated) - 70 (approx.)
Capacity (w/Standees) - 155 (approx.)
Capacity (Crush Load) - 250 (approx.)
Features - HVAC, Automated Announcements

Technical Information
Length - 88-94 feet
Width - 8' 8 3/4"
Height - 12' 5"
Interior Headroom - 6' 7"
Interior Floor Height - 14" above top of rail
Weight - 105,000 lbs. empty
Gauge - 4' 8 1/2" (Standard)
<<Operating Voltage - 750 VDC
Traction Motors - 4 AC motors per car
Traction Controls - AC Drive
Braking - Re-generative-Dynamic/Friction/TrackBrake
Average Acceleration - 3 mphps
Average Deceleration - 3 mphps (Normal) - 5 mphps (Emergency)
Max Speed - 55 mph
Carbody Construction - Corten Steel

Ok, we can apply ohhms law.

Voltage = 750
Resistance = 500ohms If charcol gary is all hot and sweaty
Resistance = 10,000 if charcol gary is dry


Resistance is a variable, as i mentioned several times it all depends on how sweaty he is body fat etc etc etc

therfore

I=V/R

volts/Resistance=current
750/500= 1.5amp
750/10,000=.075amp

The human body cannot draw 250amps.

http://van.physics.illinois.edu/qa/listing.php?id=6793

Operating voltage has nothing to do with what is being carried on the line supplying it. There are probably multiple trains on the one feed.

 

[Sea Moose]

Originally posted by: alkemyst
Most really underestimate electricity. I have had a few close calls, one had me feeling really off for months.

This is an interesting read:http://www.physics.ohio-state....ety/fatal_current.html

Yeah close calls give you a reminder of what you are dealing with. I got thrown to the floor once when i was rushing on a job. Never again will i let that happen

 

[alkemyst]

Originally posted by: Sea Moose

Originally posted by: alkemyst
Most really underestimate electricity. I have had a few close calls, one had me feeling really off for months.

This is an interesting read:http://www.physics.ohio-state....ety/fatal_current.html

Yeah close calls give you a reminder of what you are dealing with. I got thrown to the floor once when i was rushing on a job. Never again will i let that happen

My last was in my workshop. I was working with live current (yeah stupid I know)...however the previous owner didn't wire anything by code. It seemed he used whatever lead he wanted (he also used 4 wire in a 3 wire setup adding an extra variable).

Luckily it was my screwdriver that found that voltage, yet I felt some of it during the disassembly.

When I re-side my workshop i am going to redo all the electrical.