Young Players & The Dangers of Mains Electricity

[German_EE]

Board members may remember that I have a regular visitor to my workshop, the son of a neighbor who is rather eager to learn as much as he can about electricity and electronics. At seven years old he is at a very impressionable age and here is where I have a small problem.

What do I do about mains powered devices?

I know that everything in my workshop is safe, if it wasn't then I would not be using it, but there is nothing to stop my curious young friend from pulling the back off the nearest TV set (with the mains connected) and having a look around. I need some way to teach him about the dangers of mains electricity but without turning him into a younger version of Photonic Induction where, having experienced something dangerous, he wants to try it again and make a bigger bang.

So far all I have is a promise from him that all his experiments will be battery powered. What else can I do?

[Simon]

Explain that anything with a wire going to the wall that is plugged in is dangerous which I guess you have. Show him an insect killer (don't mention that it's 6KV in reality) and what it does to insects. Do sparks demonstrate dangers ? show how the mains will destroy even a power resistor whereas the batteries won't.

Teach him to use a power supply brick and to treat it as a black box not to be opened.

[tautech]

It's not JUST mains.
Youngsters must get in their heads, there are tools to see this invisible stuff that BITES.
We already have the benefit of experience, your and me, but how do we effectively pass it on?

Some thoughts. No particular order.

Get or make a battery powered electric fence, a very simple one will look very innocent until you touch the wrong end. Old lawn mower ignition is a good experience, just a gentle rotation while holding the lead will do the trick.
Boys especially can be tactile learners, a harmless shock will make them think twice about where their fingers investigate.
My first shock was from a small engine ignition lead at ~10 yrs old.....45 yrs later and I still haven't forgotten.
Visual aids can be good too, set the electric fence to jump a tiny gap(after he's been shocked) then take him to an engineers to observe welding.
Warn him, if you ever find out he's been doing stupid stuff, don't come back.
Get him a DMM, even an old AVO, turn the process into a project, get manuals, demonstrate safe use, get Croc clips for the leads(safer for nervous hands).
Glass fuses are impressive when they blow, remember safety glasses.
End of rant.

Never had any problems with my 2 boys, their mother wacked their fingers if they went near power sockets. Every kid is different, you'll have work out what suits him.
Good luck.

[tggzzz]

I know that everything in my workshop is safe, if it wasn't then I would not be using it,

So far all I have is a promise from him that all his experiments will be battery powered. What else can I do?

Is a soldering iron safe? Life is about understanding, predicting and avoiding unacceptable risks, but I'm sure you know that!

Ultimately, if he "wants" to hurt himself, he will. If that is his personality then you should keep him out of your workshop. I have come across children (of any age) like that. If, on the other hand, he is curious and inexperienced but listens and understands and acts appropriately, then you'll have great fun.

I used these techniques with my daughter, so they might be relevant:

• get him to describe a situation in which he was in pain, then say that the equipment in the workshop could cause more pain for longer
• tell him stories about how you had lucky escapes, and why you really don't want them happen again
• tell him that everything can hurt him if he misuses it
• tell him that if he uses things properly, he will be OK - and that you will show him how to do things properly
• make sure he knows to ask before touching/using new things, and then do an informal "risk assessment" with him
• make sure that he doesn't try to cover up his mistakes - he should learn from them
• deliberately stage a small accident, and show him how you work out why it happened and how to avoid it in the future
• let him realise that fear/panic are unhelpful. (When somebody at school had the chemicals in a test tube catch fire, he calmly put an asbestos mat over the flame and extinguished it. The teacher looked up, saw what happened, and said "Well done, carry on")
• vaccinate him, e.g. give him a 20kV static shock (e.g. a Milty Zerostat) and make him realise mains is much worse

and most importantly, sit near him while he is doing things, so you can let him get near trouble - before you deliberately go "cough cough" to warn him that he's treading on thin ice.

That last technique also works when they are on the internet/web, and when they are learning to fly a glider. (Since you in Germany you will have plenty of opportunity to let them start learning to fly at 12 before going solo at 14! Such youngsters are mature beyond their age)

[Ian.M]

Batteries only is no guarantee of safety.  By age 13 I had a 1.5KV stack of date expired but still good 90V dry batteries!   

At that age there is rarely enough common sense for self-preservation against invisible hazards without continuous reinforcement.  Discuss the issues with the parents so they know he's promised NOT to mess with mains powered stuff and what to watch for.  Spare mains plugs or detatchable mains leads must not be kept in an accessible location.  Explain to the parents which types of appliances are likely to have dangerous high voltage capacitors or readily accessible dangerous, toxic or corrosive substances inside (e.g CRTs, large lithium batteries or Asbestos insulation)   Any other electrical/electronic junk is fair game for dismantling, but any mains leads must be cut off and mains plugs MUST be destroyed by cutting the pins off before he's allowed to open them.   Suggest he asks you first before dismantling anything complete in case its a candidate for an easy/cheap repair.  Assist in salvaging components he can use and by soldering long enough leads for breadboarding onto them.

Consider finding/building him a safe current limited low voltage PSU.  If you build it, use tamperproof case screws.

[Simon]

hm is he into taking stuff apart or making stuff from scratch ? making stuff from scratch is more controllable as he only has what he is given to mess with, I'd tell him that existing appliances don't have anything useful in them.

[opty]

• vaccinate him, e.g. give him a 20kV static shock (e.g. a Milty Zerostat) and make him realise mains is much worse

When I was around 10yo (and stubbornly didn't believe electricity could be dangerous) my father allowed me to get controlled 220v shock (through a Christmas lights chain though). I still remember this 'funny' event, my shock (and my mother screaming at my father - what probably even strengthtened my perception of seriousness of the situation  ) But point is, it did teach me a sound lesson about voltate/current.

Perhaps you could give the kid a lighter to tear down with piezo-electric element to play with later?

[tggzzz]

• vaccinate him, e.g. give him a 20kV static shock (e.g. a Milty Zerostat) and make him realise mains is much worse

When I was around 10yo (and stubbornly didn't believe electricity could be dangerous) my father allowed me to get controlled 220v shock (through a Christmas lights chain though). I still remember this 'funny' event, my shock (and my mother screaming at my father - what probably even strengthtened my perception of seriousness of the situation  ) But point is, it did teach me a sound lesson about voltate/current.
Perhaps you could give the kid a lighter to tear down with piezo-electric element to play with later?

Alternative: find an old electromagnetic relay and wire it up in such a way that when power is applied the contacts open, which remove power, which.... Connected to a battery this makes a nice spark-gap transmitter (ahem), and provides a suitably shockign experience.

[Ian.M]

@Simon: If you lie to a child and they catch you out, you loose their respect and they are far less likely to keep any promises they have made to you.   IMHO its not worth risking that when the internet is full of instructions and videos of salvaging cool stuff from gadgets and appliances that the child is highly likely to encounter.  Better to have clear policies on dismantling stuff in that house agreed with and enforced by the parents.

The bug-zapper demonstration may be worthwhile but for %DEITY%'s sake get the parents fully involved before planning ANY safety demos or similar education.

If you introduce him to relay circuits, he's likely to find for himself the buzzer configuration and find out that back EMF bites! That would be a good point to introduce the bug zapper and a newspaper article of a local death by electrocution (as a local newspaper article wont be too graphic but should 'hit home').

[smjcuk]

• vaccinate him, e.g. give him a 20kV static shock (e.g. a Milty Zerostat) and make him realise mains is much worse

When I was around 10yo (and stubbornly didn't believe electricity could be dangerous) my father allowed me to get controlled 220v shock (through a Christmas lights chain though). I still remember this 'funny' event, my shock (and my mother screaming at my father - what probably even strengthtened my perception of seriousness of the situation  ) But point is, it did teach me a sound lesson about voltate/current.
Perhaps you could give the kid a lighter to tear down with piezo-electric element to play with later?

Alternative: find an old electromagnetic relay and wire it up in such a way that when power is applied the contacts open, which remove power, which.... Connected to a battery this makes a nice spark-gap transmitter (ahem), and provides a suitably shockign experience.

This was my first zap experience on a radio shack 100-in-1 kit. I built it by accident and gave myself a zap. Then I did it again. Then I found a relay inside something else and made a bigger more painful one. Then I zapped my sister. Then I got told off. Then I learned (I'm a slow learner )

[Simon]

@Simon: If you lie to a child and they catch you out, you loose their respect and they are far less likely to keep any promises they have made to you.   IMHO its not worth risking that when the internet is full of instructions and videos of salvaging cool stuff from gadgets and appliances that the child is highly likely to encounter.  Better to have clear policies on dismantling stuff in that house agreed with and enforced by the parents.

If e is learning to design with new parts then salvaged parts are of no use at the moment. Moving on to how to salvage higher value and harder to find parts like transformers etc can come later.

[opty]

We are talking about 7 year old boy here. In all seriousness a battery and a few basic components to do a flashing diode and beeping thing should be just enough. Anything above 9V is out of question, imo.

You will probably achieve more by showing him a proper methodological approach, following/exaggerating safety rules and maintaining a tidy desk...

[zerorisers]

pfffffft. The mains has never hurt me.  When I was a kid i had a few shocks from the mains. I just sat there because it felt funny. I have not yet been shocked by a capacitor and am scared to sh*t to get shocked by one.  I have been induced to high voltage but never anything like that. Always when working on something if I get shocked by a transformer I'm fine, but if I get near big caps I turn it off and hit them with a prybar.

[KerryW]

Teaching electrical safety by giving him a shock is like teaching fire safety by setting his hair on fire.

Tell him about Galvani and dead frogs.  Luigi Galvani discovered that electricity causes muscles to contract.  He was 43 at the time.  I discovered the same thing at age 3.  We lived in a trailer park, and one of the neighbor kids dared me to grab their awning pole.  Due to a miswiring, it was hot and I could not let go.  Fortunately, the kid's father heard my screams and rushed out and pulled me off.

Between that and my Navy training, there are 3 lessons:
1 Never intentionally take a shock
2 Don't wear rings or watches when working with electricity
3 Never work with electricity alone

You should also equip your shop with groung fault devices.

[Simon]

pfffffft. The mains has never hurt me.  When I was a kid i had a few shocks from the mains. I just sat there because it felt funny.

That is just childish, I left another forum because it has such statements of stupidity from so called knowledgeable people. 

[rolycat]

pfffffft. The mains has never hurt me.  When I was a kid i had a few shocks from the mains. I just sat there because it felt funny.

That is just childish, I left another forum because it has such statements of stupidity from so called knowledgeable people. 

Well technically zerorisers is a child - he is 17 according to his profile. And he does not describe himself as knowledgeable, but as a 'young noobie'.

Having said that, 'noobies' should be aware that if you treat mains electricity casually and have not been seriously hurt, it is because so far you have been lucky, not because it is remotely safe. Part of the danger is that the shock you get can differ wildly according to where you are, what else you are touching, the humidity and many other things over which you have little or no control. A mild shock today could be fatal tomorrow.

[BradC]

2 Don't wear rings or watches when working with electricity

It took me quite a while to explain to my (now) wife why I don't wear any jewelery, and therefore why I'll never actually wear a wedding ring. Once she understood the concept of the surface area significantly reducing the resistance to shock she's never even mentioned it.

Now *this* is a wedding ring. Symbolic, and never to be worn in anger.

[Zero999]

pfffffft. The mains has never hurt me.  When I was a kid i had a few shocks from the mains. I just sat there because it felt funny.

That is just childish, I left another forum because it has such statements of stupidity from so called knowledgeable people. 

Don't forget he's in the US with only wimpy 120VAC for mains. He should come over to Europe and connect himself up to the real mains. 

It's not JUST mains.
Youngsters must get in their heads, there are tools to see this invisible stuff that BITES.
We already have the benefit of experience, your and me, but how do we effectively pass it on?

Some thoughts. No particular order.

Get or make a battery powered electric fence, a very simple one will look very innocent until you touch the wrong end. Old lawn mower ignition is a good experience, just a gentle rotation while holding the lead will do the trick.
Boys especially can be tactile learners, a harmless shock will make them think twice about where their fingers investigate.
My first shock was from a small engine ignition lead at ~10 yrs old.....45 yrs later and I still haven't forgotten.
Visual aids can be good too, set the electric fence to jump a tiny gap(after he's been shocked) then take him to an engineers to observe welding.
Warn him, if you ever find out he's been doing stupid stuff, don't come back.
Get him a DMM, even an old AVO, turn the process into a project, get manuals, demonstrate safe use, get Croc clips for the leads(safer for nervous hands).
Glass fuses are impressive when they blow, remember safety glasses.
End of rant.

Never had any problems with my 2 boys, their mother wacked their fingers if they went near power sockets. Every kid is different, you'll have work out what suits him.
Good luck.

You could show him some scary photos of people who have been seriously injured by electric shock.

It's common sense really. The fact it's used as a method of execution should be enough to deter anyone with any sense from sticking their fingers in the sockets.

[Simon]

On a European system to get a "funny" electric shock you just need to take the house main earth wire from the earthing point of the house in one hand and touch the wall with the other hand........

[Lightages]

Scaring the shit of a 7 year old with horrible pictures, dying bugs, and shocks, are all likely to make him too afraid of the subject to continue. He is 7, and at that age he will only remember the fear and drama, not the lesson.

As said before, children learn by observation. Always demonstrating proper procedure and being consistent is what will work the best in the end. Explain calmly that anything that plugs into the wall can be dangerous and demonstrate proper procedures with some examples. Give him some things that are safe to work on himself, and have a collection of things put aside that you insist that he only touches when you are together.

[jlmoon]

I have had a service lab for over 30 years now.  Back during my sons formative days,  they grew up in this environment, I demonstrated to them (hoping they would learn 'common sense') the effects of what I consider high power and the various attributes and derivations of.   In various ways I demonstrated how you can derive energy transfer in the form of Heat, Light, Sound and the by products of these.  Such as how electricity can act like a hammer, you just can not see the hammer hiding within the wires.  Sparks & Fire were pretty impressive to them when charging up large high voltage caps and making them pop or when you can take a high power audio amplifier (they were thinking those speaker wires were harmless!) and dump the raw power into some nichrome wire loads turning them into glowing red hot curly things and catching paper towel on fire, not to mention the lethal voltages present on those wires.  To this day, I truly believe these common sense lessons instilled into them a bit of respect for power in general.  When working with mains based equipment they continue to call dad over to do their dirty or risky business.  Basically it is all about COMMON SENSE and how people perceive that.  My teachings must have worked!   

[mikeselectricstuff]

pfffffft. The mains has never hurt me.  When I was a kid i had a few shocks from the mains. I just sat there because it felt funny.

Yea but in the USA you don't have real mains - only 110V!
Stick your finger in 240 of Her Majesty's Volts & you'll know all about it for sure 

[jlmoon]

pfffffft. The mains has never hurt me.  When I was a kid i had a few shocks from the mains. I just sat there because it felt funny.

Yea but in the USA you don't have real mains - only 110V!
Stick your finger in 240 of Her Majesty's Volts & you'll know all about it for sure 

LOL.  Mike, I hope I never run into a chic named that.  No here in the USA we have 120 and 120 you just have to work hard a using one leg as the common or return.     people have tried though!

[tggzzz]

pfffffft. The mains has never hurt me.  When I was a kid i had a few shocks from the mains. I just sat there because it felt funny.

Yea but in the USA you don't have real mains - only 110V!
Stick your finger in 240 of Her Majesty's Volts & you'll know all about it for sure 

When I was holding a neutral in one hand and lightly touched a live thyristor can with a finger on the other hand, both biceps contracted very rapidly and caused me to drop the circuit (fortunately).

Personally I'm at least as concerned by the EHT on a CRT's capacitor, and am aware of the stories regarding dielectric absorbtion.

[Simon]

pfffffft. The mains has never hurt me.  When I was a kid i had a few shocks from the mains. I just sat there because it felt funny.

Yea but in the USA you don't have real mains - only 110V!
Stick your finger in 240 of Her Majesty's Volts & you'll know all about it for sure 

I thought yankee volts and her majesty's volts where the same (unless there's a bloody imperial volt too now!) it's just that he majesty packs twice as many.