Shock vs. Electrocution

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Electrocute:
1) to execute by electricity.
2) to be killed by electric shock.
See also, Electrocuted, Electrocuting & Electrocution

Folks, you can obtain many electrical shocks in a life time, but you are only allowed one electrocution. :checked: Just thought I’d point that out.

When I was a child my friend’s dad lost one of his arms working on high voltage power lines. Every time a kid asked him about being electrocuted, he first corrected them by explaining how he suffered from a severe electrical shock.;)

I hooked up a transformer in reverse once while I was experimenting, I lit up on 1200 volts or so. It was a very bad experience and I felt it through both arms and in my chest. When I work on tubes I use only one hand with my test probe and I keep my shoes on. I think it is a good practice regardless how low the voltage is.

I was on an electrical crew working in a factory when one of the guys dropped his linesman pliers across a 600 amp buss. The pliers exploded leaving almost nothing behind and the guy was blown near 20 feet back and was blind for a few moments. He was slightly physically hurt but walked to the ambulance with the medics. It was weeks before we could get back in that place to finish the work.:att'n:

Cheers,

Shawn.
 
The right sequence of connecting GND and Plus is depending on if you put the battery in or out:

We have to avoid a short circuit if the plus gets connected to the car chassis with the wrench by accident. So simply don't srew around at plus, when GND is connected. Means:

Putting the battery out:
Disconnect GND first.
Disconnect Plus second.

Putting the battery in:
Connect Plus first.
Connect GND second.
 
Shawn has touched on a good subject. There are never too many reminders on electrical safety.

Today I made a mistake by not checking the voltage left in a power supply I was building and I took several hundred volts.

If I had been more careful I would have installed a bleader resistor in the supply. I was in a hurry to try the supply so I didn't.

Today I was lucky. In the future I might not be.

Something to think about ........

Thanks for the reminder Shawn.:bigeyes:
 
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Hi burnedfingers,
Excellent point to add to Shawn's.

Keep in mind that there are amplifiers that do not discharge some rather high DC voltages. Even after a day. Always measure first!!

I've been zapped a few times through carelessness and stupidity. Some people only get zapped once and it's game over.

-Chris
 
burnedfingers said:

Today I made a mistake by not checking the voltage left in a power supply I was building and I took several hundred volts.


Burnedfingers,

So you are basically telling us that you picked an internet moniker and then waited for something to happen? Aren`t you sorry now you didn`t call yourself `multi-millionaire lottery winner` instead? :D
 
When I was about 13 or so my dad and I were working on an old house he bought to rent. In the shed there was a cable hanging very low from the roof with two bare ends exposed (no doubt ready for a lamp fitting). Little Quasi thought, " I wonder if they're live" and grasped an end in each hand.

They were. My whole body shook uncontrollably and somehow I was able to let go.

I ran to the rear of the yard to collect myself and re-regulate my breathing without being seen by my Dad, who would have killed me if he found out electricity nearly did.

I recall it took about a week for me to get over it.

Imagine a world without Quasi.....friends sometimes note that Quasi now has one hand in his pocket while the other is poking around.

For the record it's 240v @ 50Hz down here.

Cheers
 
Today I made a mistake by not checking the voltage left in a power supply I was building and I took several hundred volts.

I have done this as well. I try to always have an LED on my PS boards powered after the bridge (from caps to resistor to led). If there is charge in the caps, LED is on. Even with bleeders (like to use those as well) it can take some time to drain.
 
I remember as a kid, trying to plug in a lamp in my dark bedroom. I was holding the two prongs of the plug between my fingers, so that my finger tips could feel where the holes were. Zap. Luckily most of the charge went finger to finger on the same hand, but I still felt it all over.

I went into the next room where my older brother was watching television, and told him I just zapped myself. He asked, "Did you see anything?" I asked what he meant. He then told me that when you get zapped like that, your eyes light up.

Yes, I soon zapped myself again to see if I could see in the dark. I like to blame the stupidity on the first shock and a lingering detatchment ;)

Sorry for the lighter (ha) story.

Both of my brothers are electricians, and can tell lots of good stories that make you think twice.
 
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Joined 2005
Always check to make sure high voltage electronic devices are unplugged from the mains if you're going to perform repair work or are going to leave them unattended for any period of time. I opened up a CRT monitor one time to replace some components inside to see if I could get the tube to work again and plugged it in and turned it on to see if it worked. It didn't and I got called away to do something else. 15 minutes later I came back and accidentally touched the CRT while the monitor was still plugged in and turned on. Luckily the current went down the side of my body and not across my chest. I often wonder if that incident is the reason my arm muscles twinge unexpectedly once in while...

That may also be part of the reason I have come to appreciate efficient speakers that work very well with low power class d amplifiers :scratch2:
 
TomWaits said:
Electrocute:
1) to execute by electricity.
2) to be killed by electric shock.
See also, Electrocuted, Electrocuting & Electrocution

Folks, you can obtain many electrical shocks in a life time, but you are only allowed one electrocution. :checked: Just thought I’d point that out.

I hooked up a transformer in reverse once while I was experimenting, I lit up on 1200 volts or so. It was a very bad experience and I felt it through both arms and in my chest. When I work on tubes I use only one hand with my test probe and I keep my shoes on. I think it is a good practice regardless how low the voltage is.

I was on an electrical crew working in a factory when one of the guys dropped his linesman pliers across a 600 amp buss. The pliers exploded leaving almost nothing behind and the guy was blown near 20 feet back and was blind for a few moments. He was slightly physically hurt but walked to the ambulance with the medics. It was weeks before we could get back in that place to finish the work.:att'n:

Cheers,

Shawn.

I recall building a Tesla coil when I was 14... :cool:

Unfortunately, I wound the secondary 3' coil on a 3" glass core (being chemically inclined even back then, it was the only long thin insulator I had laying around... :xeye:

I had trouble fixing it to the board the project was mounted on, so I just stuck it in some modeling clay and fired it up... uh..oh...

Got about a 14" spark off the top... ozone spewing out all over the room, deafening crackling from the high frequency fixed spark gap driving the thing... felt like Dr. Frankenstein and all that... when the thing started to fall over... while running...:smash:

I reached out to.....test the true meaning of high frequency "skin effect" b4 I even knew what that meant... :bigeyes: lucky for me the thing was tuned to ~500Khz

...about 5 minutes and 60KV later, I woke up with the thing running on the ground, a HV burn on my hand, and a REALLY sore butt... I learned to turn things off and use a fail safe device on all future projects

... and NOT to grab live projects no matter what was at stake...:hot:


John L.
 
taking a hit

One I do rember was years back when fiddling with my diy 100Mhz single tube (ECC83) FM transmitter.

In this particular circuit there is a variable capacitor between the anode's of each half of the tube which regulates the frequency you were transmitting.

I had a tool for trimming, but could not find it when needed. So i grabbed the capacitor with thumb and index finger and :bulb:
forgot to switch of the 400V DC.

Well, it did hurt for some days, and i'm just a bit more careful since then.
 
Re: Re: Shock vs. Electrocution

auplater said:


I recall building a Tesla coil when I was 14... :cool:

Unfortunately, I wound the secondary 3' coil on a 3" glass core (being chemically inclined even back then, it was the only long thin insulator I had laying around... :xeye:

I had trouble fixing it to the board the project was mounted on, so I just stuck it in some modeling clay and fired it up... uh..oh...

Got about a 14" spark off the top... ozone spewing out all over the room, deafening crackling from the high frequency fixed spark gap driving the thing... felt like Dr. Frankenstein and all that... when the thing started to fall over... while running...:smash:

I reached out to.....test the true meaning of high frequency "skin effect" b4 I even knew what that meant... :bigeyes: lucky for me the thing was tuned to ~500Khz

...about 5 minutes and 60KV later, I woke up with the thing running on the ground, a HV burn on my hand, and a REALLY sore butt... I learned to turn things off and use a fail safe device on all future projects

... and NOT to grab live projects no matter what was at stake...:hot:


John L.


Skin effect as an explanation why you don`t get a shock from low power tesla coil type devices when handling the discharge is a MYTH. The currents DO penetrate the body and actually travel along the nerves which are much better conductors of electricity (that is how they work) than the surrounding tissue. Such bodily contact with such high frequency, high voltage causes long term nerve damage.

The lack of shock pain is because the nerves cannot react to the HF waveform, like the ears cannot hear above a certain frequency, although the eardrums can still be damaged by loud HF sounds.

You likely came in contact with the primary coil circuit which would have definitely put you on your rear end. Lucky you are around to tell about it.

How do I know this? I have some experience with these devices.
 

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Re: Re: Re: Shock vs. Electrocution

rcavictim said:



Skin effect as an explanation why you don`t get a shock from low power tesla coil type devices when handling the discharge is a MYTH.

You likely came in contact with the primary coil circuit which would have definitely put you on your rear end. Lucky you are around to tell about it.

How do I know this? I have some experience with these devices.

The skin effect reference was "tonque in cheek"...I've worked for NRAO, JPL, NASA and many other rf operations building waveguides for decades now

Nope, I grabbed the secondary about halfway up to try to stop the fall... if I'd gotten hit with the 15 KV primary circuit, I'd probably be dead, as the spark gap spark was about 1/2 inch thick...

John L.
 

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I remember a few years ago I was working on an arcade game. In order to remove the chassis to take back to the lab and test it, (the games are in the field) the anode wire from the top of the tube must be discharged and removed. After discharging the tube completely, reparing it, then comes the fun part of installing it a couple of hours later. You had to either remove the whole tube or reach one arm up behind the neck in the back of the machine and use "feel" to find the anode plug socket for the anode plug....or I could've taken the whole tube out...:rolleyes:. Now I was sure I had discharged that tube compleatly before by shorting the plug to gnd, but when searching for the anode plug :bulb: I knew I had found it :hbeat:. I did almost compleatly discharge it, or it may have gained some charge, but I only got a quick tingle...enough to gain attention but no residual damage. However, if that tube was fully charged....

:att'n:ALWAYS respect high voltage equipment and never put yourself in a position where you can't see exactly what you are doing.;)
 
What shocking tales!! Heheeheee...

Lucky to be alive from messing around with a Paillard tube radio 50 years ago. That's also when I was taught some rather nice additions to my budding vocabulary while the house fuses got blown during the old man's favourite detective serials.

The biggest danger here is repetitive jobs you have done many times before...as you get cocky about your own abilities.

Thanks for reminding me!

bulgin
 
CBS240 said:
I remember a few years ago I was working on an arcade game. In order to remove the chassis to take back to the lab and test it, (the games are in the field) the anode wire from the top of the tube must be discharged and removed. After discharging the tube completely, reparing it, then comes the fun part of installing it a couple of hours later. You had to either remove the whole tube or reach one arm up behind the neck in the back of the machine and use "feel" to find the anode plug socket for the anode plug....or I could've taken the whole tube out...:rolleyes:. Now I was sure I had discharged that tube compleatly before by shorting the plug to gnd, but when searching for the anode plug :bulb: I knew I had found it :hbeat:. I did almost compleatly discharge it, or it may have gained some charge, but I only got a quick tingle...enough to gain attention but no residual damage. However, if that tube was fully charged....

:att'n:ALWAYS respect high voltage equipment and never put yourself in a position where you can't see exactly what you are doing.;)


You experienced the memory effect that plagues capacitors with glass as a dielectric. They do not release all of their charge when you short them out. After discharging the cap with a shorting wire, charge will continue to leak out of the dielectric recharging the plates allowing another spark, smaller than the first, to be had upon re-shorting with the discharge wire. Your hand became the 2nd discharge path.
 
Auplater,

I was not suggesting that you were misinformed about skin effect, but the truth is MOST tesla coil types, including trained EE`s are not aware of the truth regarding skin effect and how HF tesla currents flow in human tissue. The human body is not a homogenous metal conductor.

That coil looks familiar. Did I see it years ago on the Tesla List at pupman which I left because in practice it became the `perpetual newbie list`?

The contact I suggested that may have occured with the primary circuit could have been capacitive in nature. Did the ground connection on the bottom of the HV resonator become disconnected when the coil tipped? That would have likely knocked you for a loop without physical contact with the primary tank.

I was offered a job at NRAO, GB when the GBT was in the design stage which I turned down. That would have been a good career choice if I could handle beating someone else`s drum, to their rhythm.
 
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