20 years ago when my children were younger, i was constructing a tube amp. I was working long hours and was busy taking care of the kids with sports, school work etc. Point is only time I could work on my project was late at night when the kids we asleep. Well, this night I was finishing up the amp and testing the voltages when my young son called to me from his room. He could not get to sleep and I read him a story ("Tink Tock Takes a Trip"...pictures with 3 words per page) I read him this because I was impatient and wanted to get back to the project. He fell asleep and back to the project I went. I was on my knees and went back to it. Bam!😱 the circuit was energized with 600v dc.my whole body was paralyzed and I fell away and off the contact. Just something I think about often....and I still have "Tink Tock Tuck Takes a Trip", great book! Can't wait for the movie.
Be Careful
Be Careful
I also was doing construction work in the basement late at night some 20 years ago. One night, after finishing my work on power supply with a 500 uF 400 V electrolyte, I decided to discharge the capacitor by shorting it with a screwdriver. The flash was blinding, and the sound was like pistol shot point blank. Screwdriver's tip was gone. I previously discharged capacitors with a screwdriver - just a little spark, no big deal. But those were NOT 500 uF 400 V capacitors...
When I was very young I decided I would help my dad replace the old light switches in his summer house, I was barefoot, I was sweaty and the power was on. I don't need to tell you that I got severely shocked, I remember feeling it in the lower back of my spine, I could literally feel contractions at 60Hz... Probably not as bad as 600V DC but still....
Unfortunately, AC can cause more severe muscular contractions than DC.
Alternating currents in the range 10 - 30mA result in a likelyhood of muscular contractions which may be so strong that the victim cannot let go of the wire that is shocking him.
An alternating current level >30mA introduces the probability of ventricular fibrillation.
The corresponding figures for DC are 30 - 120mA and >120mA.
At a frequency of 50Hz, even a voltage as low as 33V rms can kill someone with a weak heart. The corresponding DC (ripple-free) safe limit is 70V.
All figures are for normal dry conditions.
Information courtesy of SSERC (Scottish Schools Educational Resource Centre).
Alternating currents in the range 10 - 30mA result in a likelyhood of muscular contractions which may be so strong that the victim cannot let go of the wire that is shocking him.
An alternating current level >30mA introduces the probability of ventricular fibrillation.
The corresponding figures for DC are 30 - 120mA and >120mA.
At a frequency of 50Hz, even a voltage as low as 33V rms can kill someone with a weak heart. The corresponding DC (ripple-free) safe limit is 70V.
All figures are for normal dry conditions.
Information courtesy of SSERC (Scottish Schools Educational Resource Centre).
I am fortunate to have not yet take a DC hit above 300 vdc. On an antique radio I went to test the volume control center lug for buzz with my finger (60hz injection). By accident I touched the tone control instead. B+ runs thru many tone controls on radios. I actually pinched it not just touched it. Got my attention but I let ago. I now use a probe lead for this. The worst AC I have taken is 120 vac line voltage. Several times while doing some scratchbuilding in high school. The worst was once I took it on my tongue as a kid while baking a cake. I drew a spark off my tongue and it knocked me back and I saw colors for a few seconds. If the cord falls out of the mixer into the batter....don't lick the batter out of the recessed cord terminals and unplug the cord from the wall. I don't ever want to experience 220 440 or worse.
Some odd 30 hits on 230AC line until now, lost count. I have fenced (the sport, foil and sabre), so reflexes are fairly good (also usefull when driving on my motorbike). Everytime I promise to take drastic measures to avoid a next hit, until that next hit hit.
Recently, I had to remove CR2032 coin-batteries from old equipment. Each charged and over 3V. How to carry them all, some 25, from one place to another? Stacked them together and press firmly on both ends with your hands to lift them all at once. I went off like a grenade. Not found them back all yet.
Recently, I had to remove CR2032 coin-batteries from old equipment. Each charged and over 3V. How to carry them all, some 25, from one place to another? Stacked them together and press firmly on both ends with your hands to lift them all at once. I went off like a grenade. Not found them back all yet.
Many years ago I was working in an old Graflex photo flash and discharged the bank of 450V caps from one and to the other. Quite a jolt. One hand had little bumps and the other little holes where the current went in and out. With what was left in the caps, I still welded a screwdriver to the cap terminals.
200 joules, meaning about 2000uF @450V. I'm much more careful now.
200 joules, meaning about 2000uF @450V. I'm much more careful now.
Been zapped too many times to count, especially as a kid in the Florida heat and humidity learning the hard way about hot chassis radios and TV's, often outdoors in a metal tool shed, as I wasn't always allowed to bring my latest score from someone's trash inside the house.
Worst "shocking experience." Lightning!
I worked second Shift at the Motorola plant and spent many mornings on Ft. Lauderdale beach and the surrounding waters on a 14 foot Hobie Cat sailboat. A storm had come up and it was nearly time to head west, so I had pulled the boat on to my trailer and was in the process of tying the mast into its transport fixture. I was standing barefoot on the wet sand while holding the 20 foot aluminum mast when lightning hit the big water tower across the street.
The next thing I remember was being flat on my back in the sand about ten feet from the boat with rain in my eyes and a bunch of people gathering around me. They were "like dude, you just got hit by lightning." No, if I had been hit directly, I would be dry and crispy, not wet, alive, and acting stupider than normal.
A few people did explain the hit on the water tower, and by this time I was normal enough to finish my tie down and hop in the van. I was driving away when the paramedics showed up. I saw a couple people point at my van, so I hit the gas and vanished into traffic. I just didn't want to be late for work.
I did go to work that night, but was rather useless. Everything I drank or ate tasted like metallic vinegar, I was seeing stars and random flashes of light for a while, and just didn't feel right, but all ill effects wore off after a few days, and I was back at the beach on my Hobie about a week later.
Worst "shocking experience." Lightning!
I worked second Shift at the Motorola plant and spent many mornings on Ft. Lauderdale beach and the surrounding waters on a 14 foot Hobie Cat sailboat. A storm had come up and it was nearly time to head west, so I had pulled the boat on to my trailer and was in the process of tying the mast into its transport fixture. I was standing barefoot on the wet sand while holding the 20 foot aluminum mast when lightning hit the big water tower across the street.
The next thing I remember was being flat on my back in the sand about ten feet from the boat with rain in my eyes and a bunch of people gathering around me. They were "like dude, you just got hit by lightning." No, if I had been hit directly, I would be dry and crispy, not wet, alive, and acting stupider than normal.
A few people did explain the hit on the water tower, and by this time I was normal enough to finish my tie down and hop in the van. I was driving away when the paramedics showed up. I saw a couple people point at my van, so I hit the gas and vanished into traffic. I just didn't want to be late for work.
I did go to work that night, but was rather useless. Everything I drank or ate tasted like metallic vinegar, I was seeing stars and random flashes of light for a while, and just didn't feel right, but all ill effects wore off after a few days, and I was back at the beach on my Hobie about a week later.
Having once (briefly) experienced 480VAC, I'm sure that you don't.
Actually, it measured 495VAC.
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We have 480 in out plant. Several years ago some "yutes" tried to get the transformer for its copper I guess, they got away with nothing but there was evidence that someone got hurt.
Now the chain-linked fence has concertina wire and security cameras.
Ever throw a charged "door-knob" cap to someone?
Yeah, charged it on a TV set's ultor terminal, then tossed it to a classmate. The involuntary loss of muscular and vocabulary control earned us both a trip to the principal's office.
This was the electronics class where I learned how to melt tubes, and the teacher was just as interested in blowing stuff up as I was. On a dare, we hooked all of the class in series hand to hand, then wired the ends to a Variac in a game of "chicken". There were two of us who always won those challenges...….we would both wind up working at Motorola for a long time......coincidence?
Being the boss, I was unable to have such fun. That all happened after I went home for the day.
My mom's friend's husband built Tesla coils. He once had me over to play with one of the devices, we did the glass pane crack in the spark gap (that one will kill you, he said) and the top spike spinner, the florescent tube trick, the yardstick trick. He said that discharge coming off the top spike wouldnt hurt you, it would just run along the surface of your skin. Then he wanted to teach me the "dirty" version of how to remember the resistor color code... I told him I didnt know the colors the normal way, so that was "maybe another time".
His son had a 4 member band, "stone axis". I tried to convince him to use his fathers Tesla coil as one of the drummers cymbal stands, as the sparks would just run along his skin after crossing the drumstick - plus it would look cool. They...never bought into my idea...and I've yet to see it done.
The only time I can remember getting severely whacked was when I had a runaway Briggs engine and I thought I could grab the spark wire off the plug end "one handed". Nope. Then I tried a metal socket wrench handle short to the engine chassis. Nope - not while holding it in place till the engine spins down with a bare hand. Gave up on the spark plug wire finally and threw the choke lever closed.
His son had a 4 member band, "stone axis". I tried to convince him to use his fathers Tesla coil as one of the drummers cymbal stands, as the sparks would just run along his skin after crossing the drumstick - plus it would look cool. They...never bought into my idea...and I've yet to see it done.
The only time I can remember getting severely whacked was when I had a runaway Briggs engine and I thought I could grab the spark wire off the plug end "one handed". Nope. Then I tried a metal socket wrench handle short to the engine chassis. Nope - not while holding it in place till the engine spins down with a bare hand. Gave up on the spark plug wire finally and threw the choke lever closed.
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I shared an office with a guy who tried to wire a car ignition coil to the door knob... He couldn't get it to work so I hooked it to a power audio generator, tweaked the frequency for optimum output. It worked well. Every time one of us left the room the other one turned it on of course - but we were good at opening the door with feet, or other insulated devices.
Then I had a "smart" idea. I discretely turned it on while we were in the room... The other guy went to go to the bathroom, grabbed the handle and literally flew back across the room in a shower of expletives. It certainly worked - a bit too well! We dismantled it after that!
Then I had a "smart" idea. I discretely turned it on while we were in the room... The other guy went to go to the bathroom, grabbed the handle and literally flew back across the room in a shower of expletives. It certainly worked - a bit too well! We dismantled it after that!