I had more than my share of stupid encounters with electricity, which fortunately left me alive and able to talk about them. These "blonde moments" did furnish enough "learning experiences" for me to have avoided any unexpected encounters in the past 30 years or so. The most memorable:
My first car was a 1949 Plymouth. It had a 6 volt electrical system with a breaker points ignition. I converted it to 12 volts, so I could install an 8 track player (hey it was 1970), and added a CD ignition system. I was troubleshooting a dead cylinder when I got the brilliant idea to remove the plug wires one by one with the engine running. That car had a large curved hood, a large engine compartment and a relatively small engine. To reach the engine you leaned across the fender and most of your upper body was underneath the hood. It was a typical summer day in Miami and I was shirtless and covered in sweat. I grabbed the first plug wire and yanked it off of the plug. The lightning bolts shot out of the plug wire jumping to my hand causing my body to convulse and bang my head against the hood every time that wire sparked. A flash of light went off in my head with every spark. I could not let go of the wire, so this repeated for what seemed like eternity until my legs collapsed and I fell down ripping the plug wire out of the distributor. I lie on the ground in a semi consious state for a while. There was blood all over my head from repeated contact with the hood and I couldn't stand up for several minutes. Some memories fade with time but this one remains perfectly clear after 39 years!
That car also tought me that you can receive a noticible electric shock under the same sweaty conditions by holding a metal wrench and contacting the 12 volt battery. It was a very mild shock but I wasn't expecting it.
Another memorable event:
We had a Jacobs Ladder set up in the high school electronics lab. I was sitting at the bench throwing paper airplanes with pencil markings on them through the arc when a numb nuts decided to see what the arc would do to the pencil itself. Of course it shocked him causing him to knock the whole thing into my lap, launching me across the classroom. No one was seriously hurt, but the teacher decided that the Jacobs Ladder was not safe and must be dismantled. I used the transformer to make a seriously wicked Tesla coil that scared the school administrators so badly that it wasn't allowed in the science fair.
Looking back at that high school electronics class which was built in 1960, it seems that electrical safety was not observed or even understood. All of the work benches were metal and grounded. We learned on old radios and TV sets that were often line powered without power transformers. Students got shocked often, but no one ever got seriously hurt. I performed some spectacular "electrical deconstruction" experiments in that lab. Melted tubes and exploded capacitors were common.
I didn't really realize how dangerous this place was at the time, but I have since figured it out. I have taken my lifes electrical safety lessons, added some facts and figures and put them all here:
Electrical Safety
My first car was a 1949 Plymouth. It had a 6 volt electrical system with a breaker points ignition. I converted it to 12 volts, so I could install an 8 track player (hey it was 1970), and added a CD ignition system. I was troubleshooting a dead cylinder when I got the brilliant idea to remove the plug wires one by one with the engine running. That car had a large curved hood, a large engine compartment and a relatively small engine. To reach the engine you leaned across the fender and most of your upper body was underneath the hood. It was a typical summer day in Miami and I was shirtless and covered in sweat. I grabbed the first plug wire and yanked it off of the plug. The lightning bolts shot out of the plug wire jumping to my hand causing my body to convulse and bang my head against the hood every time that wire sparked. A flash of light went off in my head with every spark. I could not let go of the wire, so this repeated for what seemed like eternity until my legs collapsed and I fell down ripping the plug wire out of the distributor. I lie on the ground in a semi consious state for a while. There was blood all over my head from repeated contact with the hood and I couldn't stand up for several minutes. Some memories fade with time but this one remains perfectly clear after 39 years!
That car also tought me that you can receive a noticible electric shock under the same sweaty conditions by holding a metal wrench and contacting the 12 volt battery. It was a very mild shock but I wasn't expecting it.
Another memorable event:
We had a Jacobs Ladder set up in the high school electronics lab. I was sitting at the bench throwing paper airplanes with pencil markings on them through the arc when a numb nuts decided to see what the arc would do to the pencil itself. Of course it shocked him causing him to knock the whole thing into my lap, launching me across the classroom. No one was seriously hurt, but the teacher decided that the Jacobs Ladder was not safe and must be dismantled. I used the transformer to make a seriously wicked Tesla coil that scared the school administrators so badly that it wasn't allowed in the science fair.
Looking back at that high school electronics class which was built in 1960, it seems that electrical safety was not observed or even understood. All of the work benches were metal and grounded. We learned on old radios and TV sets that were often line powered without power transformers. Students got shocked often, but no one ever got seriously hurt. I performed some spectacular "electrical deconstruction" experiments in that lab. Melted tubes and exploded capacitors were common.
I didn't really realize how dangerous this place was at the time, but I have since figured it out. I have taken my lifes electrical safety lessons, added some facts and figures and put them all here:
Electrical Safety
Over the years I've collected more than enough shocks of various kinds to wonder why I'm still sucking air...
One of the most memorable was around age 15 and involved one of the many motorized contrivances that my brother and I built. Built from some soap box derby wheels, the front half of a bicycle, some 2x6 lumber, a 2.5HP Briggs and Straton gas engine an many other re-purposed parts. While attempting to do a power slide at full speed and power, the drive V-belt flew off and the throttle stuck because the throttle cable was too short. Said small gas engine was screaming at high RPM at full throttle and no load. The method of powering off the engine was to pull the spark plug cable off the spark plug. In the moment of excitement I grabbed the spark plug cable and pulled it off to kill the engine. Pulled too hard and ended up with the metal clip for the spark plug firmly grasped in my hand while my other hand was still on the handle bars. WOW! I could not let go until the engine had almost stopped turning over. I don't know how long it takes a small engine like that to slow down from 7000 RPM+ but it seemed like it was forever...
Different frequencies feel different... Got across a Fluke calibrator that was putting out 250VAC at 1Khz. Very different feel than 60Hz...
The worst shock happened working on a scope at work many years ago. Went to pull the scope forward on the work bench. Left hand was on the equipment rack. Right hand reaches for the scope to pull it forward. Ring finger on right hand touches the anode lead of the CRT. Arm to arm 7Kv. I got away from the shock by kicking with my legs to roll my chair away from the bench. Caused all the muscles in my chest to contract. Spent a couple of hours connected to an EKG monitor at the nurses station. After about an hour my body started twitching. It was like my brain was doing a self test to see what was still connected as each muscle group only twitched once. Felt like I had the flu for several days after. Root cause of shock was the CRT anode dam, a plastic cover that is glued with RTV over the anode button to which the anode lead is soldered was misplaced by about 1". Several visual inspections including the one I did missed the error.
I could go on but don't think it's necessary...
One of the most memorable was around age 15 and involved one of the many motorized contrivances that my brother and I built. Built from some soap box derby wheels, the front half of a bicycle, some 2x6 lumber, a 2.5HP Briggs and Straton gas engine an many other re-purposed parts. While attempting to do a power slide at full speed and power, the drive V-belt flew off and the throttle stuck because the throttle cable was too short. Said small gas engine was screaming at high RPM at full throttle and no load. The method of powering off the engine was to pull the spark plug cable off the spark plug. In the moment of excitement I grabbed the spark plug cable and pulled it off to kill the engine. Pulled too hard and ended up with the metal clip for the spark plug firmly grasped in my hand while my other hand was still on the handle bars. WOW! I could not let go until the engine had almost stopped turning over. I don't know how long it takes a small engine like that to slow down from 7000 RPM+ but it seemed like it was forever...
Different frequencies feel different... Got across a Fluke calibrator that was putting out 250VAC at 1Khz. Very different feel than 60Hz...
The worst shock happened working on a scope at work many years ago. Went to pull the scope forward on the work bench. Left hand was on the equipment rack. Right hand reaches for the scope to pull it forward. Ring finger on right hand touches the anode lead of the CRT. Arm to arm 7Kv. I got away from the shock by kicking with my legs to roll my chair away from the bench. Caused all the muscles in my chest to contract. Spent a couple of hours connected to an EKG monitor at the nurses station. After about an hour my body started twitching. It was like my brain was doing a self test to see what was still connected as each muscle group only twitched once. Felt like I had the flu for several days after. Root cause of shock was the CRT anode dam, a plastic cover that is glued with RTV over the anode button to which the anode lead is soldered was misplaced by about 1". Several visual inspections including the one I did missed the error.
I could go on but don't think it's necessary...
my highest was when i put the turn table aux leads in to the back of tl12 i had back then.
as i was only about 12 i just put my hand round the back and with out looking put the connectors into the 2 free holes on the power adjustment socket.
flash-bang i'm stuck to the ceiling on the other side of the room with my legs against the wall.
cartoon time look down and thank god i'm above my brothers bed, expect a soft landing.
but..oh no, fall from great hight, then bounce of the bed and land up sidedown in the middle of the room on my head.
as i was only about 12 i just put my hand round the back and with out looking put the connectors into the 2 free holes on the power adjustment socket.
flash-bang i'm stuck to the ceiling on the other side of the room with my legs against the wall.
cartoon time look down and thank god i'm above my brothers bed, expect a soft landing.
but..oh no, fall from great hight, then bounce of the bed and land up sidedown in the middle of the room on my head.
I stuck my arm in my fish tank, little did I know the seal on the heater had failed, got kind of a nasty shock when I put my other hand in...Does that count?
i had that happen too! maybe was my first electrical shock. Plenty of minor 120v shocks since then...
Had an electrician to my house when I moved in. I forget exactly what he was testing, something w/ the phases on my breaker box. He just took two fingers of one hand and started crossing the distribution bars with them...
I was shocked! (not literally) He said "it's just 120v"
I´ve seen something similar, We had an old power supply expert involved with a product design project at work once, and he said he could feel the difference between voltages between 50 and 400v!
He was almost completely hairless, but I dont know if there was any causality there.
My most memorable zaps have nothing to do with tube amps. Not that tube amps have not ocassionally bit me...
#1: In high school I worked for a local radio station. "Assistant technical director", they called me, which meant I was a high school kid with a 1st class FCC license, so I could take readings and sign logs.
The station was a 5KW AM station with a directional antenna system. One of the measurements we were required to make (don't remember if it was daily, weekly, or what) was an antenna base current measurement. Basically you went out to the antenna tuner shacks and logged the reading on an RF AC ammeter. To get an accurate reading you had to kill the modulation for a second, so we had a button wired up so that when you pushed it in the shack, it killed the modulation back at the transmitter so you could read the meter.
(I loved that transmitter, by the way. Late 1940's vintage RCA, with big MV rectifiers, and a bunch of 813's for drivers.)
In the shack were some tuning components, including an inductor made of copper tubing that stood about 5 feet tall, which provided a DC ground to the antenna (which was a 300 foot tower). The modulation kill button was located above that inductor.
So, I was out there, at night, to make a reading. I reached up for the button, and I remember seeing a big fat blue arc between my arm and the top of the coil connected to the tower. My arm pulled away in reflex, and in the process took out the light bulb in the shack. So I stood there, shaking, in the dark, with about 500V RMS @ 590kHz all around me. Finally my vision recovered enough that I got outside.
#2 - In college I worked at a particle accelerator (Cornell U. synchrotron). I worked on particle detector electronics. The particular detector I worked on was a lot like a geiger counter - basically chambers of some gas with wires strung across it. The chamber was normally charged to a high voltage - don't remember exactly what it was, over 1kV - and the AC signals from the wires were amplified and measured.
I was assigned to do leak checking on a detector one day. The detector was installed in the area where the collisions happened (forget what it was called), which meant it was about 15 feet above the floor. The detector was charged by a substantial power supply (and the detector itself was a pretty large capacitor). I was up on a ladder with a gas sniffer probe looking for leaks.
I knew the detector was charged, so I kept my left hand stuck in the back of my pants. Good thing I did.
Somehow I got one of my fingers in a position that managed to discharge the detector. It felt a lot like hitting your finger with a hammer - not like a shock, just a blow, then numbing pain. I pulled my hand away and grabbed the ladder with my other hand. My arm went numb up to my shoulder, and I inched down the ladder to the floor. Then I sat down and reflected on the fact I was lucky that I had that hand in my pants, and that I didn't fall off the ladder. Feeling slowly came back over about an hour's time, and only a small white spot on my finger remained.
I quit that job soon after, after a routine radiation survey found a lead box with Uranium in it had been forgotton on a shelf above my workbench. My radiation badge never came back unusually hot, but that scared me. I kid you not...
Pete
#1: In high school I worked for a local radio station. "Assistant technical director", they called me, which meant I was a high school kid with a 1st class FCC license, so I could take readings and sign logs.
The station was a 5KW AM station with a directional antenna system. One of the measurements we were required to make (don't remember if it was daily, weekly, or what) was an antenna base current measurement. Basically you went out to the antenna tuner shacks and logged the reading on an RF AC ammeter. To get an accurate reading you had to kill the modulation for a second, so we had a button wired up so that when you pushed it in the shack, it killed the modulation back at the transmitter so you could read the meter.
(I loved that transmitter, by the way. Late 1940's vintage RCA, with big MV rectifiers, and a bunch of 813's for drivers.)
In the shack were some tuning components, including an inductor made of copper tubing that stood about 5 feet tall, which provided a DC ground to the antenna (which was a 300 foot tower). The modulation kill button was located above that inductor.
So, I was out there, at night, to make a reading. I reached up for the button, and I remember seeing a big fat blue arc between my arm and the top of the coil connected to the tower. My arm pulled away in reflex, and in the process took out the light bulb in the shack. So I stood there, shaking, in the dark, with about 500V RMS @ 590kHz all around me. Finally my vision recovered enough that I got outside.
#2 - In college I worked at a particle accelerator (Cornell U. synchrotron). I worked on particle detector electronics. The particular detector I worked on was a lot like a geiger counter - basically chambers of some gas with wires strung across it. The chamber was normally charged to a high voltage - don't remember exactly what it was, over 1kV - and the AC signals from the wires were amplified and measured.
I was assigned to do leak checking on a detector one day. The detector was installed in the area where the collisions happened (forget what it was called), which meant it was about 15 feet above the floor. The detector was charged by a substantial power supply (and the detector itself was a pretty large capacitor). I was up on a ladder with a gas sniffer probe looking for leaks.
I knew the detector was charged, so I kept my left hand stuck in the back of my pants. Good thing I did.
Somehow I got one of my fingers in a position that managed to discharge the detector. It felt a lot like hitting your finger with a hammer - not like a shock, just a blow, then numbing pain. I pulled my hand away and grabbed the ladder with my other hand. My arm went numb up to my shoulder, and I inched down the ladder to the floor. Then I sat down and reflected on the fact I was lucky that I had that hand in my pants, and that I didn't fall off the ladder. Feeling slowly came back over about an hour's time, and only a small white spot on my finger remained.
I quit that job soon after, after a routine radiation survey found a lead box with Uranium in it had been forgotton on a shelf above my workbench. My radiation badge never came back unusually hot, but that scared me. I kid you not...
Pete
Not audio related but funny just the same. I'm sitting in the rear cockpit of an F4C fighter aircraft checking out the radar system and noticed that the radar scope needed a few tweaks. Pulled the scope out of it's mount, removed the cover and slid it back in and fired everything up again. After deciding what adjustments are needed I grab my little INSULATED tweaker (the pots are HOT, like 20KV hot, but I KNOW that so that's why I'm using an insulated tool. I stick my head down between my legs under the instrument panel and try to do the alignment, DAMN the pot is too tight to adjust, it's a locking pot. Soooo I grab my UNINSULATED socket and proceed to break the nut loose with it and you can figure the rest out on your own. I NEVER did that again.
Craig
Craig
Probably this one. It was backup to the 50 kW model at my first radio station. I know exactly what you mean. Old machines like that were close to the ultimate expression of accessible engineering, before miniaturization hid the workings. And what an incredible sight lit up.
First experience was in kindergarden. I had a D cell, lamp and a couple of strips of wire. while laying down for a nap, the battery was dead and I noticed the (unprotected) wall socket at the head of my cot. I told the teacher the battery did it.
Second was at the age of about 17 (aournd 1968). I was disassembling a TV for tubes and parts, and had it on my workbench in the garage. I thought I flipped the bench power switch off, but hit the wrong switch. One hand on the chassis and un-insulated wire cutters in the other hand.
I woke up across the garage on the floor.
That was my last, and hopefully will be my last such experience.
Second was at the age of about 17 (aournd 1968). I was disassembling a TV for tubes and parts, and had it on my workbench in the garage. I thought I flipped the bench power switch off, but hit the wrong switch. One hand on the chassis and un-insulated wire cutters in the other hand.
I woke up across the garage on the floor.
That was my last, and hopefully will be my last such experience.
I just remembered one day at school that I may never forget. During our breaks,a friend and I would always go over to the carpeted area and scuff our feet to build up a good static charge,and zap each other..mostly harmless fun. Then one day I remembered how TV screens usually built up a static charge on the front of them,we had a TV right there in the classroom,so I stuck my hand on the screen and moved it around to collect the charge from the surface,all while scuffing my feet around. The screen must have acted like a big capacitor,because when I went to touch my friends hand,there was a big arc,and we both ended up on the floor with burn marks on our fingers. Surprised the crap out of both of us,and we stopped playing that game.
Two hits: One was 1200V DC from my home made ham SSB transmitter at highschool - the PS was four old 300V B+ radios wired in series stacked above each other in a wooden frame (!!!). Had a multimeter in the output tube anode feed to monitor current, and I reached up to change ranges... I was instantly on the ceiling looking down at my body in the other corner of the room, and this awful burnt flesh smell. Picked the body up and walked it up and down, it felt weightless for a couple of minutes...
2/ Fender Twin reverb amp on the bench, had to turn it over and I reached inside the case for a good handhold - thumb right across the back of the mains switch (240V AC in Australia) - I threw that amp right up and over my shoulder onto the concrete floor behind me, also accompanied by burnt flesh smell!
Regards, Allen
2/ Fender Twin reverb amp on the bench, had to turn it over and I reached inside the case for a good handhold - thumb right across the back of the mains switch (240V AC in Australia) - I threw that amp right up and over my shoulder onto the concrete floor behind me, also accompanied by burnt flesh smell!
Regards, Allen
I've seen a lot of the HV accidents with descriptions like this. Are you guys literally being thrown (by your own muscles, I guess) up against the ceiling, and you take a sort of mental snapshot there before you're out and find yourself on the floor, or is it an almost out of body/near death type thing?
It was 100% an out of body experience. I felt no surprise being out of the body, seemed totally natural to me, and I just knew I had to pick the body up again or it would die. I just "sort of" dived into it, stood it up and started walking it around the room.
Happened to me one other time, during a near big time car crash - I jumped clear out and watched my car not hit the other car from about 50 meter above - then had to get back into the "driver's seat" or the car would have crashed 100 meters further down the road.
Regards, Allen
Happened to me one other time, during a near big time car crash - I jumped clear out and watched my car not hit the other car from about 50 meter above - then had to get back into the "driver's seat" or the car would have crashed 100 meters further down the road.
Regards, Allen
ReVox G36 Bites Back
My favorite is the ReVox G36 that bit me in high school....
I was working on a G36 for someone and somehow touched the contacts on the power switch, which it being Brussels was connected to 240V/50Hz. I made a very solid connection, and the muscles in my left arm contracted very violently.. I watched in helpless fascination, and worse while the theme song of "The Six Million Dollar Man" played in my mind, as my arm swung up in what seemed like TV style slow motion, and hit me very hard on the forehead.. I had to laugh (hysterically) even as I looked at the burn marks on my finger. Fortunately I am aware of no permanent damage..
My brother who was in the room at the time thought it was pretty funny too..
Edit: I see I posted the same story to this thread 4yrs ago..
My favorite is the ReVox G36 that bit me in high school....
I was working on a G36 for someone and somehow touched the contacts on the power switch, which it being Brussels was connected to 240V/50Hz. I made a very solid connection, and the muscles in my left arm contracted very violently.. I watched in helpless fascination, and worse while the theme song of "The Six Million Dollar Man" played in my mind, as my arm swung up in what seemed like TV style slow motion, and hit me very hard on the forehead.. I had to laugh (hysterically) even as I looked at the burn marks on my finger. Fortunately I am aware of no permanent damage..
My brother who was in the room at the time thought it was pretty funny too..
Edit: I see I posted the same story to this thread 4yrs ago..
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