Electrical Shock Log Book

[JohnRoberts]

109VAC @ 375 uA

I don't know if this qualifies as a full blown shock, but yesterday while using my trusty Kitchen-aid mixer, I felt a tingle when a metal spoon in my right hand was touching the metal bowl, and my left arm burshed up against the metal trim on the edge of the wood kitchen counter. 

I confirmed with my VOM that there was 109V between mixer chassis and metal trim, then with the same VOM I measured 375 uA of AC current. These appliances are  going into a GFCI outlet that would trup at 5mA of current leakage, but the 2 circuit wiring in my house means that all of the leakage, from all of my appliances plugged into that outlet will combine and show up on all grounded chassis that are floating.

In an ideal world I would pull new 3 circuit (grounded) wiring. Not crazy to at least ground my kitchen and laundry room. A few hundred uA are not really dangerous but annoying.

JR 

 

[dfuruta]

Put my hand across a cap inside of a broken tube turntable I was turning into a dreamachine;  thing had been unplugged for a good while, so I wasn't expecting it.  Had a nice jolt and localized numbness for the next few minutes.

 

[Matt Nolan]

Ooh, blimey, well not so many lately, but plenty when I first started tinkering in my mid teens. I think I got the count up to 12 mains shocks. That was 240V AC in the UK back then. I think we've standardised to something more in line with the rest of Europe now, 230 +5% -10% or something like that.

Repairing P.A. gear, CRT TVs, etc. The worst one was when I was working on a P.A. power amp stage in my dad's basement. I was toggling the mains on and off, changing things, probing things. My hand was on the earthed, metal mains socket box, my other hand was in the amp. I had a "lapse" and my toggling got out of phase. One hand earthed, the other hand with fingers on 240V AC. By far the worst mains shock I ever got. Straight across the chest. Real gripping spasms and shaking arms so it was hard to let go. That may have been the last one. I think I decided to get more careful after that.

Though, there was that one time when I phoned a TV repair shop for advice and they told me to connect a 60W light bulb between the electrode on the back of the CRT (not the gun) and chassis ground to get a diagnostic based on whether it lit up or not. I don't know if they deliberately didn't tell me, for a laugh, or if they assumed I must have known what I was doing. I must have been 15 or 16 years old. But I didn't discharge the tube first. Even though it was switched off, it was only just a few seconds earlier. It was a pretty big TV. We're talking a few kVs of static charge. I was thrown across the room. It felt like being kicked in the chest by a horse and having my fingers snapped in a mousetrap.

Since then I've been quite well behaved. The occasional screwdriver tip vaporisation when I've been lazy and tried to fix something without turning it off and then fumbled.

No belts so far from building valve mics and their PSUs. So far...

 

[CJ]

june 22, 4:43 PM,

376 volts DC across left pinky, Marshall Mk 2 HT fuse was blown due to shorted Electro Harmonix EL34 tube,
did not replace fuse, so C1 still charged, Zap!

no biggy,

 

[joaquins]

june 22, 4:43 PM,

376 volts DC across left pinky, Marshall Mk 2 HT fuse was blown due to shorted Electro Harmonix EL34 tube,
did not replace fuse, so C1 still charged, Zap!

no biggy,

You should be more careful, you're taking all this topic for yourself!

Discharging across the fuse seems a bad idea, when someone HAVE to open the case (because the amp is blowing fuses) the caps remain charged! Bleeding resistors just across the caps looks like a better idea...

JS

 

[FETlife]

Had a dodgy extension lead intermittently putting 150v AC onto earth connection and hence chassis of equipment. Mains is 230v so not sure how it was only 150v but never mind, things in the bin!

 

[CJ]

tuesday 3:31 PM 7-7-15  139 volts (after human bleeder resistor applied)

pwr tubes pulled on JCM 900 dual reverb to check for hi fi osc and burned grid resistor, so HV cap not drained thru tubes,

left hand to right index finger knuckle,

 

[JohnRoberts]

A shock from hand to hand is bad because the current passes through your core and by your heart. Good news a cap will usually run out of charge before you expire, but a large enough cap who knows?

The old "keep one hand in your pocket" when working around tube amps may apply here.  ;D

JR

 

[Gustav]

"I wonder what that sound is"

"Yeah, better stick my head in real close and take a look"

I dont know if it counts, but it gave me quite a shock when the hissing cap opened up and took a leak on my face.

Luckily, it only hit my glasses.

(25V cap in 30V territory. Must have thought I could get away with it when I was stuffing the board).

Gustav

 

[joaquins]

"I wonder what that sound is"

"Yeah, better stick my head in real close and take a look"

I dont know if it counts, but it gave me quite a shock when the hissing cap opened up and took a leak on my face.

Luckily, it only hit my glasses.

(25V cap in 30V territory. Must have thought I could get away with it when I was stuffing the board).

Gustav

Well, you have developed the reflex to move away when hearing a cap, and and you got a cheap one this time... A friend of mine has a story about one of those but it ended with the cap case nailed to the ceiling and a black stain all around, good luck he had already moved himself out of the way. Now days caps doesn't do that anymore, they got reliefs to brake the casing and only leak, not blowing pieces of aluminum all around.

JS

 

[JohnRoberts]

Decades ago when I was a young technician working on then novel switching power supply, I managed to blow up a film cap. They don't put pressure relief on those puppies. Luckily I was away from my bench when it blew because it sounded like a firecracker, and littered my bench with a rain of small pieces of foil.

JR

 

[CJ]

thursday 12:51 PM 

Vox Pathfinder no power,

fuse inside chassis, left index finger across mains as we forgot to unplug the amp after the pre-test,  120 V-ac,  no big...

 

[JohnRoberts]

This is not a competition. We do not win anything for most reported shocks.

The final one probably won't be written up, at least not as a first person experience.

JR

 

[Electrobumps]

Korg MS10 2012,  Fixed a fault so excited that it was working forgot to unplug after test.  Right hand touched live connection on back of power switch/volume pot on reassemble.  240v AC right hand quite a buzz up the arm, screamed like a 12 year old girl.  A huge amount of natural adrenaline released into my body.  Which I have to say was comparable to coming up on an E......... Neither of the forementioned are clever or to be condoned. 

 

[CJ]

i am just trying to see how many times i get shocked in a year, not trying to glorify bad safety practices, but just to see if enuff shocks have been survived so i don't have to go to treatment anymore,  ;D

oh, and after yesterdays shock, we got bit again by touching the metal backs of a transistor bank for a Carvin  B1500 bass amp which gave me both rails to the left ring finger, no big, 120 dc,

 

[Axelerator]

First AC 230 v when i was 5 years old, trying to mount my blanket on my bedlight for building a tent...maybe this was good because what would happened with my blanket leaving it over a lightened bulb!

-My first (working) diy kit i made with maybe 9 years: battery to HV converter for "pulling out worms for fishing"-->never tested this , but me and my friends had alot of fun  ;D
It converted 1.5 volts to 300 volts ,sure only uA but funny.
Then came the day my parents having aparty , and my friends were also there, knowing this kit from before, so no one was
sceptical,when i invited my best friend for an shock execution... :-X. i build a ´electric chair ´with some lead- plates i gatherd from
a nearby housebuild and a chair.
nobody knew i had changed the small lytic cap to the biggest i had around from my father (dissasambling old tv and stuff)
and i did take a 12 volt fat block akku with 6.7 ah..... ???
For everybodys luck my friend just completly killed the chair we had tied him to in the half of the first second..chair really went to pieces !
That would have been a poor party otherwise..
-after that i left electro-diying before i got to this forum

I am not going to diy tube stuff. this i leave to the pros.

 

[DaveP]

Servicing  the contacts on a 440V  heating transformer size of a large fridge in 1971.  An idiot threw a metal drum lid at me like a Frisbee and made me jump, my hand hit a 240V contact and jumped onto some metal work and hurt like hell.  He was in hysterics until I hit him.

In the African jungle in 1977 I had my face next to a metal mesh mosquito screen over the open window, while watching a tropical storm. lightning strike nearby and a spark jumped onto my nose.

1994, servicing a TV, didn't wait long enough for the tube discharge and got 20kV,  gave me a funny heart rhythm for a few minutes, na,na na no lastingggg dddammmaggge .

DaveP

 

[Unit7]

I shouldn't post in this thread because I'm the cautious type and, knock on wood, I've never been zapped. But I've followed the thread with mixed amusement and horror, and Dave's fridge story reminded me of a very good friend of mine that as a youngster in the 70s lived in a house with a couple of friends. Very poor circumstances and they had this fridge that would occasionally zap you. So it was early morning Christmas time and my friend wanted to surprise everybody with newly baked gingerbread. Time to put it in the stove, which was placed opposite to the fridge, and just as the plate in his hands touched the stove his rear touched the fridge and bam all dough stuck in the ceiling. All buddies waken of the noise and obviously not the surprise he'd aimed for.. One of those stories that in hindsight are fun. Close call.

 

[benqbasic]

I work in the HV industry you don't often come back from those shocks. I do find DC shocks from large battery banks give you sore joints though...

 

[CJ]

Tues, 11/14/17 - 1:58 PM, Marshall JCM 900, 525 VDC left hand only,

Brits too cheap for bleeder resistors, 

I'm sorry, i mean frugal, not cheap,

like pouring the booze in last in case a bomb goes off while mixing, 

US pours booze first, mixer second,