240v AC that will not give shock !?

[Reloadron]

This is one of those subjects that can run on and on. Can 240 or 220 volts cause death? Absolutely if the conditions are right. Enter all the little cute current charts we have grown to know so well when electrocution is discussed followed by the needed voltage to get the current needed to stop the heart and it goes on from there. Then enter the physical condition of the person getting shocked and the current path through the body. There are so many variables it is really hard to make a difinitive statement as to what will or will not kill you on any given day under any given conditions.

Anyone or just about anyone who has worked with electricity for any length of time has been shocked. Obviously those of us still here weren't killed. There are no shortage of dead people as a result of 120 or 240 volt electrocution. They are not still here unfortunately. I seriously doubt there is any magic involved. I have been bitten more times than I care to remember. Generally as a result of my own stupidity. However, I think I can say that the odds (if we like to gamble) are less for fatality getting bitten by 120 or 240 volts than say 480 or 4160 or whatever. The greater the voltage and available current the greater the chance of ending up dead in a nutshell.

Just My Take
Ron

 

[unclejed613]

one of the techs i work with has been hit TWICE by lightning, and he's ok. however there was a tech in our shop a few years ago that was killed instantly by the charge in the capacitor in a microwave oven. personally i can't count how many times i've been bit by line voltage or zapped by the charge on a CRT, and i did once (and only once) get popped hand to hand by 300Vdc on an antique tube radio at the age of 10. that's when i learned the one hand rule (and also that speaker frames on those old radios were at B+ potential). i have also been bit by 12Vdc batteries (in damp weather, hand to elbow). so there are a lot of factors, many of them controllable, and a few of them random, which determine how dangerous a particular shock incident is. with normal safety precautions, getting zapped in the first place should be rare. with a well planned safety procedure, it should be almost nonexistent. somebody said above that "it's the volts that jolts and the mils that kills" but it's also Ohm's Law that determines how many volts it takes to make those mils, and what path they take. but your worst enemy is your own carelessness, and occasionally lack of information. you may not know that the heat sink on the primary side of that switching supply is live, because your eyes see a large exposed piece of aluminum and your brain says it's grounded, so you go to touch it to see if the transistor is overheating. well, bucky, it's NOT grounded after all. it's a painful lesson to learn, but you won't try it again, and you will be more suspicious of large exposed heat sinks from now on. there are even audio amplifiers where the heat sinks are at the output transistor rail voltages (pioneer made some receivers like that a few years ago. the heat sinks were the large ones like the ones that they still use inside their receivers, but were mounted on plastic insulators, and all of the NPN output devices were mounted on one heat sink and the PNP devices on the other. this allowed the use of heat sink grease without mica or sil-pad insulators, but it was a very large safety hazard (especially because they were not marked as being live). getting yourself across a 120V DC (+/-60V rails) potential, especially when it's stored on 10,000uF caps can be very painful.

 

[unclejed613]

so i just looked at the original question again. the answer is actually very simple. current limit the 240Vac to a few milliamps. if it's limited to the 100mA in the original question, it will still cause a dangerous shock, so it would have to be limited to less than 10mA (although 10mA would still be within the range where you would definitely know it's there).

 

[Instrotech]

LOL nope i come from a country that has 240V/415V Australia.I am not too sure what you do for a living some thing like electronics or computers maybe ?
Anyhow as for the fear factor ,i work with 240V/415V/6.4KV/10KV/22KV ,and anything from 2Amps to 4000Amps,come work with me for a day and you might understand, you would not have to work hard to kill yourself as you put it, on a 240V 100Amp Supply.And i am pretty sure if i said touch that connection at the terminal of 100 amp supply "as seems you think it is really hard to get killed on 240 V" I would bet you that you would not touch it because, if you did ,well you would not be around to complain. "remember it is not as safe as what you make it out to be" Think of fault currents at 240v that can be produced,think of the amount of current from your supply anything over 30mA can kill you.

Quote
Obviously the higher the voltage the more dangerous, but you still have to be unlucky (or seriously stupid) to get killed by 240V.

Lets make this one easy , nothing to do with luck , it's all just pure stupidity !


The higher the voltage the more dangerous ? Remember the amps are going to hurt more than the volts.

Cheers

 

[bryan1]

Well when I got zapped by using welder in very high humidity and temperature the quack at the hospital said the me you are left handed as you are still here talking to me. What happened I was in a tunnel welding Rio and my body was soaked in sweat, my welding glove got wet and was too close to the rio. The arc jumped across went up my right arm then back down leaving a hole in the end of 2 of my fingers. The quack at first couldn't workout why the current didn't go right thru my body untill I told him the full story. Working in basically a sauna and the moisture in my arms was greater than was around my body so the current found the quickest way out 'thru my fingers'. At the mining inquiry all the commisioner said to me personally was he was glad I was still alive with no bad injuries.

At the time I was welding @ 160 amps too and yes I did go buy a lotto ticket and got no win...... go figure

So yea 240 volts and more than 35 milliamps can kill, 29 volts DC @160 amps can hurt to.......

 

[Nigel Goodwin]

one of the techs i work with has been hit TWICE by lightning, and he's ok. however there was a tech in our shop a few years ago that was killed instantly by the charge in the capacitor in a microwave oven.

Microwave ovens are the most dangerous item in a house, if you foolishly take them to pieces.

240V will only very rarely kill or seriously injure you (one a week in the UK according to figures I've found), but a microwave will almost certainly prove fatal.

I don't know anyone who has ever had a shock off one, but I know someone who knows someone

The guy in qyestion was instantly 'killed', but by a VERY fortunate turn of events their happened to be paramedics right next door and been so they were able to bring him back to life with CPR.

 

[Instrotech]

That would hurt

Are you still welding at the mines ?

 

[Instrotech]

Microwave ovens are so cheap , kind of silly of the person to try and play/fix it !

Lucky he was brought back , now he should have bought a lotto ticket !

 

[arunb]

more than the voltage its the current that's important, the higher the current the more the chances of a fatality.

Static voltages can be in excess of a million volts, but carry very little current, hence they cannot cause a fatality directly.

 

[Nigel Goodwin]

Microwave ovens are so cheap , kind of silly of the person to try and play/fix it !

Lucky he was brought back , now he should have bought a lotto ticket !

He was 'brought back', but apparently he was never quite the same afterwards