Does the project shown in this video work? And if so, is it safe?

[Maniacal Doodler]

I want to try this for fun, and possibly to trick my friends a little... Thought I'd turn to some people who knew what they were doing first as the video looks a little sketchy and I don't want to electrocute myself.

Thanks!

[exchemist]

17 minutes ago, Maniacal Doodler said:

I want to try this for fun, and possibly to trick my friends a little... Thought I'd turn to some people who knew what they were doing first as the video looks a little sketchy and I don't want to electrocute myself.

Thanks!

At the risk of being thought racist, I would NOT trust a video from the Indian subcontinent showing somebody putting a screwdriver into an electric socket. When I was in Dubai we were constantly stopping people from that part of the world from doing dangerous things with electricity. Their safety culture around it seemed non-existent. 
 

You can safely send sparks between people if you have a van de Graaf generator, but don’t even think of doing anything involving mains electricity.

[Maniacal Doodler]

2 hours ago, exchemist said:

At the risk of being thought racist, I would NOT trust a video from the Indian subcontinent showing somebody putting a screwdriver into an electric socket. When I was in Dubai we were constantly stopping people from that part of the world from doing dangerous things with electricity. Their safety culture around it seemed non-existent. 
 

You can safely send sparks between people if you have a van de Graaf generator, but don’t even think of doing anything involving mains electricity.

Doesn't this build use a battery pack though? I get what you mean about the dangers of mains voltage but this particular one doesn't seem to use it at all.

[exchemist]

32 minutes ago, Maniacal Doodler said:

Doesn't this build use a battery pack though? I get what you mean about the dangers of mains voltage but this particular one doesn't seem to use it at all.

I didn't watch it all. The guy's accent is so strong it's a real challenge to understand him. What do you think he is proposing, then?  

A rule of thumb is it's the amps that kill you not the volts. A battery sounds dangerous to me as it can store a lot of charge, i.e. can supply a lot of amps in a short space of time. A van der Graaf generator on the other hand supplies a high voltage but only stores a tiny amount of charge.

Edited June 3, 2023 by exchemist

[TheVat]

Batteries are AFAIK less dangerous because the current is DC.  It's AC that interferes more with the heart's sinus rhythm.  

But don't try it with a high amperage battery, like a car battery.   I have heard 5 mA is the ceiling for safe shocks.  That's a conservative figure, so you could factcheck that, if you have something that's like 10 mA and are unsure.  

I am uncertain of my figures, because I know a AA battery (which the video guy seems to be using) is around 50 mA (normal load) and does not seem dangerous.  But of course if you used all that battery's amp hours to charge a capacitor, it could deliver a nasty shock.  So, the moral here is: educate yourself thoroughly on what sort of circuit is being made in that video.

[Mordred]

DC is actually considered more dangerous. High DC amps can literally blow a hole through you. Also with AC you have a chance in letting go of a conductor  not so much with DC.

Either way it's the AMPS that kills 

[TheVat]

1 hour ago, Mordred said:

DC is actually considered more dangerous. High DC amps can literally blow a hole through you. Also with AC you have a chance in letting go of a conductor  not so much with DC.

 

While I can't say if that's correct or not, it is weird that multiple people in my life who worked with electrical equipment, as well as an instructor in an electronics course way back in undergrad days, all told me quite the opposite of that.  Also worth mentioning that the electric chair uses AC, because of its more effective lethality.  Is there an EE here who can account for these seeming contradictory ideas about AC v DC?  

I did find this...

Quote

Low-frequency AC produces extended muscle contraction (tetany), which may freeze the hand to the current's source, prolonging exposure. DC is most likely to cause a single convulsive contraction, which often forces the victim away from the current's source.

https://www.allaboutcircuits.com/textbook/direct-current/chpt-3/physiological-effects-electricity/#:~:text=Low-frequency AC produces extended,away from the current's source.

[Mordred]

Well ways to interpret that paragraph. Often doesn't imply always. The convulsion can also prevent you from letting go of a live conductor. 

AC will cause muscle spasms so your more likely be able to let go. From personal experience of having felt both at 20 and higher Amp services. I'd much rather be hit with AC. Trust me you can feel the difference.

 Regardless both are highly dangerous. Both can cause serious injury or death if they aren't carefully handled.

[Sensei]

On 6/8/2023 at 4:55 AM, Mordred said:

I'd much rather be hit with AC. Trust me you can feel the difference.

...it all depends on how the wires are touched, dry or wet, etc. if it is the left hand one wire and the right hand, the other wire, all the current, whether it is AC or DC, flows through the heart area, which can affect the functionality of the organ passing through..

@TheVat @exchemist

One hand on the pantograph plus rubber boots do not make/close the circuit..

(as long as the clothes are dry )

ps. Don't try at home John..

Edited June 15, 2023 by Sensei

[John Cuthber]

On 6/3/2023 at 10:31 PM, exchemist said:

A rule of thumb is it's the amps that kill you not the volts.

As a rule those are not independent variables.
Ohms law tells you how to calculate on from the other.

Does anyone know why this myth persists?

On 6/3/2023 at 11:19 PM, TheVat said:

But don't try it with a high amperage battery, like a car battery. 

Why not?
Twelve volts is twelve volts.
 

[exchemist]

1 hour ago, John Cuthber said:

As a rule those are not independent variables.
Ohms law tells you how to calculate on from the other.

Does anyone know why this myth persists?

Why not?
Twelve volts is twelve volts.
 

Surely the operation of something like a Van de Graaf generator would explain why this isn't entirely a myth? High voltage, but very little charge, so you get a shock but little current and no danger.  

[John Cuthber]

1 hour ago, exchemist said:

Surely the operation of something like a Van de Graaf generator would explain why this isn't entirely a myth? High voltage, but very little charge, so you get a shock but little current and no danger.  

What evidence do you have that the current is low?
What would limit it?

[exchemist]

Just now, John Cuthber said:

What evidence do you have that the current is low?
What would limit it?

The limit is due to the amount of static charge that can accumulate on the ball at the top of the generator before discharge occurs. There is no capacitor present. Once discharged the belt has to run for a number of seconds before a second discharge is possible. 

It's diving back into my ancient A-Level physics but, as I recall,  you can calculate the charge present on a conducting sphere to generate a given electric field strength. And you know when the breakdown field strength of air is exceeded, because that's when it discharges, to whatever object is brought a certain distance away from it. 

Thinking more about it, though, you may have a point in that the above is arguing the charge is low, rather than the current i.e. the rate of charge flow, during the instant of discharge. If it all discharges in a microsecond, ten the instantaneous current could be high, I suppose.

 

[John Cuthber]

The ball is a capacitor- that's what it's for.
 

45 minutes ago, exchemist said:

If it all discharges in a microsecond, ten the instantaneous current could be high, I suppose.

And; fast as lightning, you worked out what the issue is.

[TheVat]

4 hours ago, John Cuthber said:

Why not?
Twelve volts is twelve volts.

Thanks for asking.  (I used to tinker a bit with old cars)  With lower voltage, high amperage that flows from an automobile battery presents a strong danger of burns rather than shock.  It won't toss your heart's sinus rhythm in a blender, so it is not likely to be life-threatening.  Also worth noting that the high-voltage portion of the car ignition system IS a shock hazard. The wire from the coil to the distributor, and the wires from the distributor to the spark plugs, don’t run at 12 volts, but at tens of thousands of volts.  On a car with a high-energy ignition system, the voltage level is high enough that it can potentially interfere with your heart rhythm. So you wouldn't want to handle the coil or plug wires without wearing rubber gloves.

[xkalibur08]

I gotta say, that project looks pretty cool, but we can't be 100% sure if it works or if it's totally safe just from watching a video. It's always a good idea to do some extra research, check out reviews, and maybe even consult with an expert about electrical or any related field to get their take on it. Since he is not an expert and just doing some experiment it's better to avoid those kind of process. Safety first, right?