Big Clive video: 10mA hand to hand electric shocks

[Psi]

[EEVblog]

I haven't watched it all, but 

[Mr.B]

Fark!  My heart was racing just watching it.
That is simply borderline stupidity.
I hope nobody out there in copycat land watches that one.

[amyk]

This is not his first time:

[Mr.B]

Deathwish?

[tautech]

Deathwish?

Probably and also the handle of a dear departed member. 

https://www.eevblog.com/forum/profile/?u=107683

[Psi]

Come on, 10mA isn't "safe" but it's far from lethal except in very specific circumstances.

If he was doing that at or above 30mA i would be very concerned.

[GadgetBoy]

It takes 50-70 mA to cause a serious interruption in the heart.

[Psi]

It's not an exact science as everyone's heart has a different tolerance to current.

There have been lots of different current thresholds given by various sources about the point where it becomes 'deadly'.

It's put somewhere from 30mA to 100mA for an average person.

 
 

[Cnoob]

How is an average person defined because a 4 year old is totally different to a 30 year old and a 30 year old is totally different to an 80 year old?

[joeqsmith]

I thought the idea wasn't to show what was safe but at what point he couldn't release the probes.   I would have ran a strap to my shoulder and left one hand free. 

Interesting comment about the mid range current causing the most problems.  Does make some sense but I wonder if there is any data that supports it.   

I ran a similar test with a non-contact Fluke meter with my hand on a metal plate while holding the meter in the same hand.   I did make some sort of body model for one of these tests to avoid pushing my luck.    Basically this was done to demonstrate the meters internal network after watching a video from AEV.     

https://youtu.be/k8hhtTtWfVc?t=2632

https://youtu.be/QsRwQIuTNmE?t=412

[MT]

Electroboom soon to do a followup!

[Psi]

How is an average person defined because a 4 year old is totally different to a 30 year old and a 30 year old is totally different to an 80 year old?

All the stats/tables are intended for people working in industry. So tend to ignore people to old/young to work.

[richard.cs]

Electrical safety thresholds are mostly based on a set of research papers from the 1950s which basically involved applying electricity to US soldiers (not exactly general population in terms of age/fitness) and the occasional secretary. It's not exactly the kind of thing that could easily be repeated today.

Based on that data, which is generally accepted, 10 mA hand to hand is considered safe indefinitely for a normal, healthy person.

[janoc]

Based on that data, which is generally accepted, 10 mA hand to hand is considered safe indefinitely for a normal, healthy person.

Except how do you know that you don't have an undiagnosed heart problem? This is really a very dumb thing to do.

[apis]

Found a series of interesting slides, not sure how accurate they are though:
https://www.slideshare.net/YassirAliHassan/electrical-safety-41590043

Summary:
Unlucky that 50-60 Hz is the frequency we are most sensitive to.
Mean let go current for men 16 mA (min 9.5). For women it's 10.5 mA (min 6 mA).
Respiratory arrest has been observed at 18 - 22 mA.
Main cause of death is ventricular fibrillation and for an average sized human varies from 75 to 400 mA.

You would need to seriously zap someone to defibrillate!

Clive got a contact resistance as low as 2615 ohm, that translates to let go voltage for women of min 16V@50Hz, mean 27V. For men min 25V, mean 42V. That's less than I would have expected to be honest. For children it would be even less I assume.

Based on that data, which is generally accepted, 10 mA hand to hand is considered safe indefinitely for a normal, healthy person.

Except how do you know that you don't have an undiagnosed heart problem? This is really a very dumb thing to do.

Yes.

[golden_labels]

I wonder how many people, who are criticizing Big Clive, worked on 30VAC circuits with bare hands…

Science works and this is why Big Clive wasn’t even close to affecting his heart or chest muscles, much less the nervous system or other organs. I am really disappointed: the narrative I see in the responses is approximately the same as I would expect from people thinking “grapheme increases heating efficiency”, “power lines produce dangerous EM fields” and “mobile phones cause cancer because they microwave brain” . Fix your mental image of the situation. 230V is very dangerous, but not simply by being somewhere in the equation. Similarly there are currents which will cause fibrillation, but that doesn’t mean that any current will. And heart diseases are not magically lowering the threshold. 

My main problem with Big Clive’s experiment? If some kid will see his video, try to repeat that and harm themselves in the process, people will tear Big Clive apart. This, and not pushing 10mA through his body, is the main danger to which he exposed himself.

The second issue is the way the experiment was conducted. It was sketchy as hell. As long as Big Clive was gripping both electrodes I wasn’t expecting anything bad. But careless manipulating the mess of live wires is a different thing. This is giving a bad example.  Having a 10–30mA fuse on the input would also be nice in case something goes wrong (I know they are expensive, but $5–10 is not that extreme price too).

[janoc]

And heart diseases are not magically lowering the threshold. 

You are needlessly patronizing all the while making dangerous assumptions here. There are many other ways your heart could give out when hit by an electric current, not only by fibrilation. Had the current triggered arrhythmia (which is a common condition many have and don't even know about), he could easily have fainted - while still clutching the wire.

The issue isn't the 10mA being safe or not but that nobody, most likely not even him, can be sure they are 100% healthy. A lot of heart problems are discovered only when you collapse and wake up in a hospital with a heart attack. Why to expose oneself to danger for no reason than a few minutes of Youtube fame? Feeling lucky, punk?

[Psi]

My main problem with Big Clive’s experiment? If some kid will see his video, try to repeat that and harm themselves in the process, people will tear Big Clive apart.

yeah, but there are videos of far more dangerous things on youtube than what Clive did.

[apis]

My main problem with Big Clive’s experiment? If some kid will see his video, try to repeat that and harm themselves in the process, people will tear Big Clive apart.

yeah, but there are videos of far more dangerous things on youtube than what Clive did.

You mean the ones where Cody play with nitroglycerin (that was seriously stupid)? I prefer if Clive (and Cody) continue making videos.

People who take a lot of risks often die in accidents it seems. Not from the really dangerous stuff but they get too comfortable around danger and so they become careless and eventually do some stupid mistake and something trivial kill them. Proper safety mentality is to always mitigate risk, not constantly challenge fate.

[thm_w]

I thought the idea wasn't to show what was safe but at what point he couldn't release the probes.   I would have ran a strap to my shoulder and left one hand free. 

Interesting comment about the mid range current causing the most problems.  Does make some sense but I wonder if there is any data that supports it.   

Statistically he is right, there are a lot more electrocution deaths in US (110V) than UK (230V). Although that doesn't necessarily mean one voltage is safer than the other. I'm not sure if any study exists to actually back that up.
https://www.quora.com/Which-one-has-more-fatality-110-volts-or-220

[janoc]

Statistically he is right, there are a lot more electrocution deaths in US (110V) than UK (230V). Although that doesn't necessarily mean one voltage is safer than the other. I'm not sure if any study exists to actually back that up.
https://www.quora.com/Which-one-has-more-fatality-110-volts-or-220

That would be impossible to infer from something like that. From a purely physical point of view, 110V should be safer due to the lower voltage so it should be harder to get lethal amount of current through the body. One would thus expect lower amount of fatal injuries from it. 

However, that completely ignores the different standards between the countries (UK's being notorious for being obsessed with safety), different plug and outlet designs (safety again), general state of the wiring and levels of code compliance between the countries, etc.

Possibly even education levels and attitude of people to electricity ("Ah, it's just 110V, will be alright!" vs "YOU DIE if you even look at that outlet wrong!").

[drescherjm]

When he hit 9 mA I wanted him to give up. I did not want to watch anymore.

[dnwheeler]

...careless manipulating the mess of live wires is a different thing.

I don't think he ever manipulated live wires. The whole setup was switched by a foot switch which he only depressed during the actual tests.

I still wouldn't do it, though.

[Psi]

My main problem with Big Clive’s experiment? If some kid will see his video, try to repeat that and harm themselves in the process, people will tear Big Clive apart.

yeah, but there are videos of far more dangerous things on youtube than what Clive did.

You mean the ones where Cody play with nitroglycerin (that was seriously stupid)? I prefer if Clive (and Cody) continue making videos.

I was mainly referring to other videos where people do something dangerous but secretly fake-it for the camera so it was actually totally safe for them.
People watching don't know it was faked and may actually try it themselves for real.
The risky part of videos like that is people thinking... "it was ok for him, it will be ok for me"  when he actually never did it because actually doing so would be lethal.
And a "Don't try this at home" warning on those videos does nothing to let people know the video was faked.

Those kind of videos are way more dangerous that any video with a proper detailed safety warning at the start like what Clive did

...careless manipulating the mess of live wires is a different thing.

I don't think he ever manipulated live wires. The whole setup was switched by a foot switch which he only depressed during the actual tests.

I still wouldn't do it, though.

The foot switch only cut neutral. He picked up the resistor array a few times when it was live. However the two last resistors had a heatshrink cover, so the risk was just that he might accidentally touch the highest resistor tap and get the full 12mA.