Stupidity is the Mother of Invention?

Those are excellent Tony - thank you.

I once found someone replacing fuselinks with bits of wire. I asked how do you know the value of the wire to use? He replied "1 wire = 5 amps, easy!"

I often wonder if he is still alive.

"....I often wonder if he is still alive...."

Yes I am. Thanks for asking.

Yikes!

It looks like plumbers are moonlighting as electricians!

Famous last words: Is this hot? It doesn't look hot! ......poof!

Hey, it's juice, so of course plumbers can do it. Just don't let any juice leak out onto your fingers.

actually electrical contractors or Home Owner (shade tree) Electricians. As in....

Dear CR4, I have a problem, When ever I turn my kitchen faucet on, I get a terrible shock........

Great pictures, I'm going to add them to my collection of Stupid Electrical Tricks...

Share some others please?

Are those clamps copper to aluminum rated?

Normal Brit Std bi-metalic jubilee clips rated at xxx +/- 50% amps.

I got some hose clamps rated for 100amps/480v for sale - real cheap. Insulated screwdriver & gel filled burn blanket included.l

So, to be clear, in place of a fuse they've hammered the edges and inserted a copper pipe? Is that right? I hope that's right cause that would be awesome.

Well of course¡¡ How else do you fix the problem of continually blowing fuses¿¿

Can you say arc flash !!!

Ah yes, the fragrant pungency of copper vapor in the air early in the morning! Almost as good as the odeur of napalm.

"Arc flash". There.

So this electrician (named Noah) walks into a bar...

Oh come now. Remember the glass fuses on American cars. A .22 Cal short fit perfectly. However an spent .22 Long rifle is much safer.

As for the pictures above, those are very unsafe, they should have a loop of insulated wire making it possible to remove the "fuse" when it is live.

I seem to remember reading about someone who used a live .22LR as a substitute for an auto fuse == I think it was in an earlier Darwin's. And then there is the old penny behind the burned out fuse trick. Amazing number of those I've found over the years. Changing to circuit breakers was a great improvement. But then there was the one company that made CBs that wouldn't trip! SIGH!

I would like to add - the old rolling the blown glass fuse in the aluminium foil trick.

Frank Zappa, actually....

He sure can make that dynamoe humm.

LOL!!

I bet there is a lot more where they came from!!

Indeed, some of the bodge artistry I've seen is quite amazing, Russian and Chinese Academic's wiring up UK 13A 3 pin plugs when PAT testing was always 'interesting'...

Update: went to look at a lifting bench that is having issues, electric motor driven screw ram keeps dropping, and was asked to take a look at an old compressor that's playing up whilst I was there. The 45 year old pressure switch is worn out and has no hysteresis/dead band so it keeps switching the new motor (why the old one failed?) on and off, suggested they fit a new switch, and a contactor to keep the load off the switching elements, also the pull the tank inspection hatches and actually see if it's still safe to use (in a damp location). But the best bit was when the owner produced a brand new push button zero volts drop out start/stop contactor, his 'electrician' couldn't work out how to fit it as it's a 3 phase and neutral 4 pole contactor to a single phase supply, worked through the electricians cut leads/bodged bridge cables and got it working, the electricians answer was to fit a 13A switched fuse cable outlet, with an old nail replacing the fuse as a 2.2HP motor needs more than 13A!

A little bit of artistic license needed here.

I have got a domestic compressor that needs more than a 13a fuse for starting (sometimes it blows sometimes it doesn't).

So I made my own fuse (old fashioned 5a fuse wire x 3) soldered into a fuse cartridge (you drill a small hole in each end cap). Similarly for a spotwelder that blows a 13a fuse.

Horace40: If you insist on fiddling, you should try joining a band!

Drilling holes in fuses entices the smoke release from the circuit.

Its sad that so many countries only use a single phase for domestic housing.

Here (boasting!) we get 3 phase into every house....love it!!!!

Here those devices would have 3 phase motors....though the DB has 16 amp CBs in it, so maybe the single phase version would have worked....

Hello Andy. A 3-phase domestic supply in Germany?. Interesting - and useful. Is it 4-wire. I have never given it a thought before - you live and learn.

But I assume it reduce to single phase to each socket outlet, and what voltage? - 50Hz ?

All houses have 3 phase, or better said, all the ones I have ever looked at.

Apartments are mixed (my daughter and SIL have 3 phase into theirs, but there is usually a 3 phase (5 wire) socket in the basement for machines that blow wet plaster on walls. I have one of those too, for that exact same reason.

Also people who make their own firewood general use a saw with a 3 phase motor.....very common here.

Also, when we had big parties in the garden, especially in winter, I would run a big 5 wire ( 3 phases, neutral and separate earth) cable into the garden and supply a DB with plenty of single phase for electric cooking and heating plus music etc..

I have even helped a neigbour who had some damage due to an old DB till they got a new one installed.....

You don't need it often, but its there when you do!!

What are your line-line and line-neutral voltages? Are they unified through all Germany, or are there holdover east/west differences? (Just curious.)

Theoretically they are all identical, but the distance to the substation makes a difference. But from memory it should be 380 VAC line to line.

They are unified in Europe.

Andy: You say you run a 5-wire supply to a DB, but what do you connect to at the house, do you have 5-pin socket outlets - or is hard wired at the incoming DB.

Like Tornado, just curious.

Everyone is allowed to be curious, I am too!!

Its a large socket, european standard for 3 Phase.......

Can you guess which is earth?

Does that mean you have 5-pin sockets around the house, or just one at the incoming DB - and a long lead.

I guess the 'fat' pin is the earth.

.....and before I started work.....DB was Dick Barton.......of "Dick Barton - Special Agent" radio serial fame - with his side-kicks Jock Anderson and Snowy White.... and compulsive tea-time listening......those were exciting days for us kids.

I actually only have one 3 phase socket, in the cellar near to a window. One does not need it THAT often......

But I do have a 25 meter cable and a portable "Dick Barton" in the garage for when required.....

I'm not sure how well 3 phase current would work in homes in the US. We're not used to it. I mind a DJ I knew in NJ before I moved who plugged his amps into a 3 phase supply and fried everything. Wasn't there when he did it so don't know exactly what he did, but it was an expensive mistake and probably dangerous also.

That can only happen, anywhere, where an idiot is involved.

3 Phase and single phase plugs and sockets are completely different and impossible to plug them wrongly.

BUT, if someone attaches the WRONG plug, WRONGLY, then all bets are off...or rewires the wrong socket.......you get my drift!!!

I have even had a fully qualified electrician blow up a $100,000 printer due to mixing phase and ground if I remember correctly. He was suddenly unemployed!!

--------------------------------------------------

By the way, although I measure in our fusebox a little over 380 VAC Phase to Phase, it should be around 400 VAC....we are about a mile from the substation....I also usually get about 220VAC single phase....sometimes more, sometimes less....

I wished we had 3-phase to our residences here in the U.S., then we could have the 'good' machine tools at home.

I suspect the reason we only have single phase power to most residences is economics. Three-phase pole pigs would be considerably more expensive, not to mention carrying twice as many conductors in the distribution network.

Um, the power lines down the alley ARE 3-phase. At each pole where the transformers are, it's a set of three transformers, each taking two 'legs' as a source, stepping the voltage down from whatever they're distributing it at down to 120/240 split phase.

The 'load balancing' of the three phase is done by evenly distributing the houses between the three 'outputs' and assuming each house will pull 'about the same' power.

Unless the transformer is from 1 line to ground. Also often there is NOT 3 wires only 1 or 2. Once you get out of the city, there are a lot of places where the closest 3 phase is miles away. -- JHF

The power distribution in Chicago is 3-Phase Delta (3-wire, no ground), and the center tap of the secondary windings of the transformer are tied to earth ground at the house.

In places that are three phase Wye, you still get the center tapped secondary grounded at the house, but the nominal voltage is around 117/234V instead of 120/240V.

If a rural area is only getting two wires, then it's likely a hot and (ungrounded) 'neutral,' with the transformer's secondary windings center-tapped to produce the 120/240V service.

(Pardon me if I'm unfamiliar with power service 'outside the city,' here in Chicagoland, you can drive for miles and miles without even SEEING farmland. So it's tricky for me to keep abreast of the power needs of farming machinery.)

I understand. Arkansas is just the opposite. I came from Los Angeles 40 years ago and drove a new freeway that is less then 10 miles form the State Capitol, the banking district and the medical area. There were no buildings! I was thinking 'where is town?'.

The lack of 3 phase is a big problem for many and is hard to explain to non-electrical people.

Even now, after 40 years it is only a short drive to the country. I work on the edge of Little Rock, a 13 mile drive home puts me in the country, 1 traffic light and 2 stop signs gets me there. Thats why I don't miss LA! -- JHF

I too live "rural". Craig Co. VA is apparently about half the size of Rhode Island, has less than 5,500 residents and no three phase, except possibly to feed the school complex. BTW, one public high school, no private. One public grammar school and possibly one private. For most shopping, I travel about 25 miles to Salem/Roanoke. My urban friends complain about 'rush hour' and I look around and say "What traffic?" hving grown up in and near NYC. BTW did you know that parts of Manhattan are still using DC?

Not any more. The last of the old Edison DC power was removed in 2007.

Thanks for the update. I moved south at about that time.

That answer only applies in Arkansas, Kansas, some backward parts of Missouri, Alabama, and all of Oklahoma.

Not really. It's been a while since I left California, but I clearly remember seeing the 3 phase lines running down the main streets with a tap on 1 conductor running down a side street, the next block same thing but from a different phase, next block ditto, then back to the first phase at the next block. So, no 3 phase in the housing develoment. -- JHF

"I clearly remember seeing the 3 phase lines running down the main streets with a tap on 1 conductor running down a side street, the next block same thing but from a different phase, next block ditto, then back to the first phase at the next block."

That could only be done with three phase Wye, but in a bizarre way, since the 'return conductor' appears to be absent, meaning that they're using the ground⁽¹⁾ as the return conductor. They also would only be able to provide single phase 107 volts, instead of the split phase 107/214 that most houses (and most breaker panels) are designed around.

Notes:

1. Not Ground Wire, the ground beneath your feet. That can get pretty dangerous, unless the area is so dry the current cannot find any moist ground to flow through⁽²⁾.
2. Then again, this *IS* California, the drought has been going on so long there, most of the residents have probably FORGOTTEN what water looks like.
   

My take was that the 3 wires in the street were the 3 phases and that the transformer inputs are Delta connected, but over 3 separate house transformers, each having a single phase input and output at 220VAC.

So going to each house transformer would be 2 phase wires and a ground......

Wildly guessing only.....but only 3 wires and a ground (if I correctly understood) rather reduce the possibilities......

I found this:

Pole Mounted Distribution Transformer

Which seems to support my theory:-

Both pole-mount and pad-mount transformers convert the high 'primary' voltage of the overhead or underground distribution lines to the lower 'secondary' voltage of the distribution wires inside the building. The primaries use the 3 phase system. Main distribution lines always have three wires, while smaller "laterals" (close to the customer) may include one or two phases, used to serve all customers with single-phase power. If three-phase service is desired, one must have a three-phase supply. Primaries provide power at the standard distribution voltages used in the area; these range from as low as 2300 volts to about 35,000 volts depending on local distribution practice and standards; often 11,000 V (50 Hz systems )and 13,800 V (60 Hz) systems are used but many other voltages are standard.

Which implies to me that US streets have VERY high voltages running above them, far higher than here for example, where the houses get 230VAC from a substation.

Which is of course supplied with the higher voltage, but only one time, 3 phases, usually underground, supply.....

Isn't that more inefficient? Lower voltage 3 PH will suffer more resistive losses in the neighborhood. Line down on ground during storm is about equivalent danger. The substation should trip that circuit within a few milliseconds of a line down condition anyway.

If we all started having 3 PH appliances, and gizmos in our backyard work sheds, the next big thing would be 3 PH power inverters running off car batteries for when we take that gear camping/fishing.

The stuff that runs off motors could possibly benefit from 3 PH at any rate, since the 3 PH induction motors are beautiful instruments of motion and power.

It takes proper planning and the underground cables cost more to both purchase and install to do it properly, I have to agree, but its far safer and as you see nothing, it also looks better....

I don't know if any animals or birds get harmed by the Pole transformer system, but it appears to be quite dangerous to me looking at one....for wildlife and stupid teenagers....

I found this:-

Dr. David Carpenter, Dean of the School of Public Health, SUNY, has reported that up to 30 percent of all childhood cancers may be due to exposure to residential power lines.
Learn more:-

http://www.naturalnews.com/023078_EMF_EMFs_power.html#ixzz458xyVfg9

http://www.buergerwelle.de/assets/files/grn/omega162.htm

I think if that has any founding in fact, our "buried" cables at only mains voltages to our houses are far less likely to be a problem.....

When i see pictures like this one:-

I feel that birds could accidentally be electrocuted when they spread their wings quite easily.....

The number of bird electrocutions at pole mounted transformers is far less than stupid idiot copper thieves who want to steal conductors, and who invariably get quite a charge from it, and the pictures are not pretty.

At our house, we have doves and squirrels that are all over the distribution system at all times, and never have we witnessed an event, or the result of one. My feeling is that only very large birds as buzzards, or large hawks and eagles or gulls could be harmed, and that surprisingly feathers may be sufficient insulation to prevent high enough current to stop their heart beat.

As to "residential power lines" causing cancer, I feel that is a myth that has been debunked, with rare exception for those that might live directly under high tension transmission lines. I think parents would be better served to look at the free-radical input in their children's diet, Chinese leaded paint (maybe), and pollution from small scale "Love Canal" style dumps of things like PCB's, aromatic hydrocarbons, and diesel soot, even some red food dyes were confirmed carcinogens back in the 1970's. I hope the food industry revolved some of these matters along the way.

If overhead lines (and maybe cell phone towers if we are going to address EM radiation hazards) were actually causative to cancer, it sort of makes a good case to go back to "land line" telephones, ban cell phones, and transmit only local DC power.

There was a study some years ago that claimed that above a certain age, that we were not affected by cellphone towers and the like.....only children CAN be affected....

I do not have details only a memory, sorry. (No cellphones when I was a kid, so I DO have a memory!!)

Here, certain masts with high voltage had to have special covers made and fitted to stop bords being electrocuted, especially when it was raining....

This is not Germany, but its the same type of pylons:-

Bird Safety on Pylons

Also this is Germany:-

electrocution_of_birds_on_pylons

"I feel that birds could accidentally be electrocuted when they spread their wings quite easily....."

The wire separation is supposed to be set so the larger local birds cannot touch two wires at once.

In areas where this is infeasible, due to the size of the local raptors, a fourth wire, bonded to Earth ground, is run above the power lines, so the raptors, who always love the highest perch available, are kept safely above the power lines (most of the time, accidents do happen, and then the Bald Eagle Depository gets another specimen to use as resources when a Native American tribe is asking for eagle feathers for their religious services.)

Those links are to sites that don't seem to be credible sources. Laboratory testing has shown that the human body does not react in significant ways to EM fields, unless they are very strong, as in MRI strong.

I really don't know myself, I was just trying to be helpful....

One has to make choices in life......

Well, the birds apparently don't have trouble with it. Growing up in Jersey City, NJ it was normal to see birds perched in the wires all the time. Never any carcasses on the ground either.

Its not the wires that are the problem for birds!!!

"Which implies to me that US streets have VERY high voltages running above them, far higher than here for example, where the houses get 230VAC from a substation."

Close, you get the high voltage in the alley, and the transformers IN THE ALLEY step it down to the 'mains voltage' (I refuse to call it 'low voltage,' even though that is the official title for the 50-999V range) for the last hundred feet or so to the house.

WOW!!

No thanks!

3,000 VAC or higher (according to Wiki), is not something I would like to play with......Trees get blown or knocked down and take overhead wiring with them....forgetting what storms and tornados can also do!!!

I prefer our system.....

The NFPH (National Fire Prevention Handbook) (Assuming I haven't mangled that all to hell) has the official designations for voltage levels, as regards to fire and personnel safety:

less than 50V - Very Low Voltage, considered 'effectively harmless.' This is why your doorbell wires (24VAC) can be run through the walls with no protection.

50V and up, but less than 100V - Low Voltage, primary risk: Electrical Shock

100V and up, but less than1,000V - Medium Voltage, primary risk: Electrical Shock

1,000V and up, but less than 10,000V High Voltage, primary risk: Arc Flash.

It continues from there, but over 200V and I prefer to keep my distance from energized parts. My favorite range is working in 24VDC, that's what PLCs use, mostly, and you man get servos and solenoids that operate at that voltage, so unless the process itself requires high power, (for a heater coil, or a multi-ton press/ram, for example) the entire machine can run at 'finger-safe' voltages.

Yeah, we got all that recently during arc flash refresher course. No one wants to "play around" when there is a remote chance of copper vapor at 6000 C.

The NFPA codes are based on electric power distribution installations. They make it very confusing for electrical safety and scientists when one works in a research lab. A Piezo manipulator can require a 10kV driver that current limits at less than a milliampere. Testing one of these on a bench is safe. They hurt just like a Tazer but it's not lethal. Add several hundred feet of coaxial cabling between crystal and driver is another story. The scientist usually grasps that the motion speed of the piezo will be significantly reduced by the cable capacitance. However both safety and scientist get startled that the cable capacitance can now store enough energy to do real harm.

Then there's the myth that low voltage is safe. Ask any automotive mechanic that forgot to remove the grounding terminal of a battery first if 12V is always safe. I have 5V instrumentation banks that are fed by 1000 ampere supplies. Arc flash can and does happen at low voltage.

5V at 1000 amperes requires source and cable impedance to be what? I get 5 milliohm, but that is only if the entire 5V drops through the source and bus.

If the source is required, on the other hand, to deliver the 5V within 95% of value, then we have only a 0.25V drop, and the combined impedance to load must be less than 250 microohms!!! That must be on hell of a bus.

Then there's the superconducting magnets. They really do have zero resistance.

I don't know what kind of bus you have. I just want to watch it "leave the station".

That is from the old joke about the farmer sitting in the bus station in Seminole, TX asking about the next bus out to Hobbs, NM. The ticket master states: Well sir, the bus leaves here in Seminole at 5 pm. Farmer, "What time does it arrive in Hobbs?" Ticket Master, "Sir, the bus arrives at 5 pm. Would you like to purchase a ticket?"

Farmer, "Hell no, I just want to sit here and watch that bus take off!"

Wouldn't the bus get there at 4:30?

	Seminole, TX Download Free App
		1. Start out going north on SW 2nd St toward W Avenue A / US-62 E / US-180 E.Map	0.07 mi 0.07 mi total
		2. Take the 1st left onto W Avenue A / US-62 W / US-180 W. Continue to follow US-62 W / US-180 W (Crossing into New Mexico).Map If you reach NW Avenue B you've gone a little too far	28.5 mi 28.6 mi total
		3. Turn slight right onto E Broadway St.Map E Broadway St is 0.1 miles past E Alameda St	0.9 mi 29.5 mi total
		4. Welcome to HOBBS, NM.Map Your destination is just past S Dalmont St If you are on W Broadway St and reach N Shipp St you've gone a little too far
	Hobbs, NM

Total Travel Estimate: 29.50 miles - about 30 minutes

It's a bus, doggone it! Surely or Shirley they had to stop and let someone on/off? The old routes used to do that, especially for farm boys coming home from war.

Dem boys bounce purty gud. Y stop?

ROFLMAO one more time!

Well, I 'spose there is the bustling metropolis of Bugtussel, TX along US-62. Why they even have their OWN rest stop.

I know . . . . I know . . . .

"If the source is required, on the other hand, to deliver the 5V within 95% of value, then we have only a 0.25V drop, and the combined impedance to load must be less than 250 microohms!!! That must be on hell of a bus."

That also means the LOAD (aka, the person) has a resistance down in the microohm range, hard to get that without being submerged in salt water, or having copper wires run under your skin.

You might want to back up on that last answer. To get 5.0V to hit the load at 4.75V with 1000A current, indeed required the source and lead resistance to be 250 microohms.

The actual load resistance would be 0.00475 Ω, 4.75 mΩ. Are we clear on that point now?

I wasn't double-checking his math, just extrapolating from his numbers.

I see that somebody doesn't understand what is an arc flash.

The true statement of all DC arc flash calculation is that it is "chicken and egg" scenario, where one needs the current to get the resistance of the arc, but one needs the resistance to get the current. Also the part about maximum power transfer to the arc at 50% potential of the source being dissipated through the arc. This is true of any power application for maximum power transfer through a load resistance (for a purely resistive system).

Arc flash is apparently the only way short of a nuclear explosion to get 4th degree burns (where the flesh is simply burned away from the bones), and that is some really nasty hot plasma.

I've heard 4th decree burns described as 'charred bone/bone marrow,' so in some scenarios, (arc flash in through the palm and out through the elbow) the flesh along the forearm won't be burned off/falling off the bone⁽¹⁾, but the bones (I forget the names of the forearm pair) will have died.

Notes:

1. I hope I can brain-bleach that description out of my head. otherwise i may never be able to eat well-prepared, tender ribs again.
   

I know. Of all the ways to get injured, I think this one puts even more fear of God into me than chlorine gas. Although chemical burns, respiratory poisons really really suck.

I'm really 'gun-shy' around gasses, vapors, and fumes myself.

When I was in the Army, our barracks had this shower room that was pretty large, about 40' x 40' x 7' with no windows, one 3" drain the the center of the floor one 3" vent in the middle of the ceiling, and doorway that would not have been out of place on a submarine, it was that small. This was a Training Barracks, so multiple companies shared space in it, each one assigning X trainees to each chore.

I was in the group cleaning this shower room, and some genius decided that undiluted Pine-Sol was just the thing to clean the grout between the tiles. I was working on a section of wall opposite the door, so when the fumes became too strong, I had to cross the entire fume-filled room to get out. By the time I got through the submarine-hatch door, my lungs were burning like the CS gas training.

Due to inter-company politics⁽¹⁾, it was decided that nobody was going to be blamed, and that the incident was not going to be officially reported, which also meant that nobody was being sent off to the medics to be looked at. To this day, I still do not know what damage those caustic vapors did to my lungs, or how much of that damage has healed over time, but I still avoid any cleaners with a strong pine or citrus scent, and even 'common' soap smells can send me fleeing a room if they seem a bit strong.

Notes:

1. There's that word again, it seems to keep creeping up whenever I'm getting screwed over through no fault of my own.
   

Pine Sol is some mild alcohols and glycolic acid. The pH is 2 to 3, not very harsh. The SDS doesn't list any severe reactions other than mild irritation. The acidic component does have an LC50 of 7.7mg/L at 4 hours. So, it can kill rats. That is 7.7 parts per million if you're wondering. For comparision, you're advised to limit CO exposure to 9 ppm for 8 hours to once per year. However, we have no idea what percent of product is the acid. We can guess at it. A 40% solution of glycolic acid and water puts it in that pH range. Now go figure the room volume and the amount of Pine Sol on the floor and you can get your ppm exposure.

Add to that whatever chlorine compounds were in the water also being used for cleaning, since that low of pH value will certainly turn them into essentially HOCl (chlorine gas associated with water) and probably exceeding the PEL of about 5 ppm per 8 hour day.

The alcohols in that cleaner would probably have a higher vapor pressure than glycolic acid, which has far less vapor pressure than the parent compound of acetic acid.

I am no fan of Pine Sol being used neat, and I do not believe the instructions on the container state this is the intended use.

There are far better things for cleaning grout lines, although I suppose Pine Sol might be suitable for that, if personnel could be "evacuated" for a given radius and time.

For the safety standards, I believe a 'dry human body, fingertip to toe' is estimated to have a resistance of one MegaOhm (1,000,000 Ohms) This means to get 1 amp of current, the voltage needs to be one Megavolt, for shorter distances, say fingertip to fingertip, there's less resistance, and if the person is sweaty, or standing in a puddle, or sitting in a filled bathtub, the resistance can drop to dangerously low levels.

I'm sure we all know that it's not the volts that kill, but the volts are easier to measure, and the volts and wattage ratings will tell us how many potential amps we can get. 10kV x 1mA = 10W system, less power than a dim incandescent bulb. Add a capacitor to the output, and the rules change, I don't remember the Farad to Amp-Hour capacity ratio off the top of my head, so I'll just talk Amp-Hours. You take a 1 Amp-Hour capacitor, and charge it with a 1 amp current source for one hour, then discharge it in one second, and you get 1 x 60 x 60 = 3,600 amps. Just for a second, mind you, but a second is all you need to electrocute Mr. "Hold my beer and watch this."

This is all true. When I was at University of Illinois at Champaign-Urbana, our group was setting up a "theta pinch" experiment where we made a spectrographic spark in a tube, then passed the current from a 3-4 ft tall capacitor charged to X kV (I think it was 3-4 kV), and I have forgotten the actual capacitance value, but the current I recall (being passed through 1" thick copper 6" width, with parallel buses, and essentially one complete inductive turn around the spark tube for induced magnetic field) was upwards of 100,000 amps. The resulting compression of the spark could remove electrons from such atoms as Al down to the fifth ionization. Needless to say, even though we had this Texan in the lab, there was no beer, and no "hold my beer, and watch this."

"... the entire machine can run at 'finger-safe' voltages."

I can recall an interesting incident from my 'skoolkid' days, and an early lesson in electrical shock - both physically and mentally.

I found an old 'wireless' (they were not called radios in those days) at the rubbish dump with a big chunky HT battery (throw away and replace with a new one) and missing was the 'glass jar' accumulator (that you had recharged every so often). I was poking around inside the wireless when I suddenly got an electric shock - nothing painful as such - but definitely a shock.

I didn't really know at the time, but I guessed it was the big battery (I vaguely recall it market HT+ 90 volt)(whatever that meant - HT? volts?). I pulled the wires off and poked around again - and got another shock.

I played a trick on my friend and asked him to touch the same wires - but nothing - strange? So I touched them again - and nothing. Nobody believed I got a shock.

To cut a long story short, and I am guessing to this day, that it must have been from a 'condenser' (they were not called capacitors in those days) - in the HT circuit. Which had a residual charge, enough to give a single 'poke'.

So with the battery disconnected it would have been zero volts - but still a source of electric shock.

It is not an issue. It was finger-safe I guess. I only mention it for the novelty value.

Its a warning for kids:-

HT = Highly Touchable