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Old 19th September 2005, 04:00 PM   #1
beamnet is offline beamnet  Netherlands
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Default your 100volt plus moment

I've had some lately and was wondering if others lived to tell.

My first one was 400-600Volts dc.

Opened a Photo camera, aware of the high voltage i put it at save distance. let my screwdriver fall, wanted to pick it up, got unbalanced and grabbed right in the guts of the cam. I was affected for two weeks.

the second was last week. I bought a small flipswitch (with metal lever) for AC/mains switching. soldered the bastard in and tried switching the switch. BANG and i was laying on my bed a good 2 meters away. Opended the switsch and discoverded they forgot an insulating piece of rubber.

(don't ever open such a switch! You never want to tuch one again if you see how crappy they are constructed)

Allthough rated 250 Volts, Use insulated switches in the future!

I had a few near misses with measuring cables, accidentally plugged out of the measuring devices, but not out of the amp, leaving banana plugs loaded with 800volts in the open...

Bas
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Old 19th September 2005, 04:11 PM   #2
EC8010 is offline EC8010  United Kingdom
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So you had a mains switch with a metal toggle? Good commercial practice is to have some means of earthing such a switch (which would have prevented your accident). I'd never heard of such a precaution genuinely being needed before but use it because I'm a "belt and braces" sort of fellow when it comes to electrical safety.
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Old 19th September 2005, 04:17 PM   #3
Nordic is offline Nordic  South Africa
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hahaha too many too mention, but 2 occasions I do remember ...
One I was still pretty young and had one of these bedlamps that clamp to the headboard... anyway, sometime after I went to bed a light blew somewher in the house, and for some reason, my parents decided to come and talke the bulb from my lamp... so somewhere in the night I half woke up, tried to switch on the light, but it stayed dark... so I started feeling around where the lamp is, only to manage to stick my fingers dead centre into prongs of the now empty, and switched on lightsocket.... made a loud bang in my head and I couldn't hear anything except a loud ringing for an hour or so...

the other time, a had too many powercables needing plugs by my workstation, so I ended up with one open plug I used to just wire directly (don't do this at home kids) anyhow, this jobby was standing on the floor and so one afternoon while soldering I managed to step right onto the open plug, barefoot!
Ended up laying behind the chair I was sitting it, while the chair didn't even seem to move.

P.S. havent had one of these blonde moments in 12 years or so, some of us just won't take warnings at face value...

250V/15A is fun!
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Old 19th September 2005, 04:23 PM   #4
beamnet is offline beamnet  Netherlands
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In a house with no grounded wallplugs, i do not see how you could earth a mains switch...
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Old 19th September 2005, 04:25 PM   #5
kevinkr is offline kevinkr  United States
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Worked on a pair of Marantz 9's some 10 years ago, and one of the first things I discovered was that the power switches in both had developed a dead short to the bat when in the "on" position, connecting one side of the power line directly and inadvertantly to the chassis. These amplifiers had unpolarized plugs on them, and one of the things the owner complained about was getting an electric shock when turning them on and off.. LOL Fortunately no one was injured as both amplifiers were plugged in the same way to neutral.

My own story was as a teenager getting two fingers across the 240V mains in Brussels whilst repairing a Revox G36.. The involuntary contraction of my arm muscles while I watched in fascinated horror as my arm swung towards my face and hit me **hard** in my forehead has left an indelible memory. While very quick I even had enough time to think of the time lapse photography in the opening sequences of the "Six Million Dollar Man" and the stupid noises that accompanied it. To this day when I think about that incident I hear those noises..

I have been very careful since that time and have not had any encounters with high voltages which is a good thing since many of my designs employ voltages of up to 700V. One such 572-3 based amplifier operated on 1100Vdc, and that was an amplifier I truly feared...
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Old 19th September 2005, 04:34 PM   #6
EC8010 is offline EC8010  United Kingdom
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Quote:
Originally posted by beamnet
In a house with no grounded wallplugs, i do not see how you could earth a mains switch...
Ah, that would pose a problem. Everything you make will need to be double insulated, and as you've already decided, that means mains switches must have insulating actuators.
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Old 19th September 2005, 04:42 PM   #7
amperex is offline amperex  United States
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Default 450 VDC zap

At age 11, I was building a PS for an old WWII shortwave radio. Got across 450 vdc. I can report 45 years later never getting zapped since.

I was a bit unusual at age 11 as I like shortwave radios & taught myself the basics from reading a ARRL (Ham radio) Handbook cover to cover many times. At age of 16 everyone else was experimenting in human biology except me still experimenting in the electronics lab.
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Old 19th September 2005, 06:03 PM   #8
beamnet is offline beamnet  Netherlands
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A friend of mine had an 8Kv high capacity encounter. He was in coma for two weeks. The 3cm thick wire he was working on was molten through the concrete. The spanner he was working with was never found....

He still has concentration problems (20 years later) and reduced ability to sense things..
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Old 19th September 2005, 06:15 PM   #9
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Quote:
250V/15A is fun!

You mean you can tell a difference with 250v/100mA? Allow me to doubt this is possible in a DBT.
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Old 19th September 2005, 06:21 PM   #10
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One of the guys in the ham radio club in my high school (decades ago) thoiught it would be funny to rig up the code practice key to turn on a 1,500V power supply hooked to the metal chair frame.

On a nice warm day with no air conditioning, I went in to practice my code. I jumped over the back of the chair and hit the wall a yard or so behind me, probably still a couple feet in the air. Fortunately he'd thought to put a current limiting resistor in the circuit, but it sure didn't feel like it had been limited much.

I should have pounded that kid to a pulp - but I am sure someone has since.
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