Got bit for the first time tonight...

Started by drummer4gc, July 11, 2017, 11:06:48 PM

Previous topic - Next topic

drummer4gc

Had a practice amp donated to me as non functional, and realized (too late) whoever opened it up before me had reconnected the power input receptacle with the chassis ground wire connected to the hot pin. Working barefoot in the garage didn't help matters. Cheaper than coffee, not quite as pleasant.

Be safe kids.

greaser_au

Early on in one's life as a technician, one learns to check ground continuity.  Still, I've been bitten many times by shoddy or stupid workmanship.  >:(

david

graemestrat

I have had quite a few shocks lately, while developing some tube amp designs.

I now always make sure I am wearing shoes with insulated soles and have even taken to wearing those blue nitrile surgical rubber gloves for a bit of extra insurance. These gloves won't save you from a big bite, say over 150v but I am hoping that if I am bitten then they might reduce the severity somewhat. (by theoretically increasing your "skin resistance")

Then of course you should always try to follow the old guideline of always having one hand in your pocket, to avoid getting shocks that go through your heart.

antonis

Quote from: drummer4gc on July 11, 2017, 11:06:48 PM
Cheaper than coffee
Only if you have a reusable circuit breaker fuse..

Quote from: drummer4gc on July 11, 2017, 11:06:48 PM
not quite as pleasant.
Hmmmm...

Some guys may have very nasty habbits..

To be serious: I always check continuity between female plug GND & metal chassis and discontinuity between Hot/Neutral and GND before powering on any instrument.. :icon_cool:
(less than a minute job can ensure many instrument/operator happy working years..)  :icon_wink:
"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

bloxstompboxes

I work on portable xray equipment at work. I have an exploded working layout of the machine where I can put in and take out boards to test them really easy. Of course, that makes everything electrical exposed as well. 115V DC strangely feels the same to me as 110-120V AC.

Floor-mat at the front entrance to my former place of employment. Oh... the irony.

duck_arse

Quote from: greaser_au on July 12, 2017, 01:32:19 AM
Early on in one's life as a technician, one learns to check ground continuity.  Still, I've been bitten many times by shoddy or stupid workmanship.  >:(

david

early on in one's life is when you learn - don't let it happen. I got me a real gooden young, and a few other minor jolts, but no juice now for - many - days.
Froggy for the cup.

Mark Hammer

I got to see "the blue lights" a few times in my barefoot 2-prong-plug garage-band days.  Has a tendency to interfere with remembering the words to songs..., as well as your name, the day of the week, where you are, and a few other silly details.

All these years later, I'm still a little bait-shy about touching mic stands.

PRR

> rubber gloves .... theoretically increasing your "skin resistance"

Not. They make your hand sweat.

On a dry day, grab your ohm-meter hand-to-hand. You may be 100K Ohms. Put on the gloves for 10-20 minutes, whip/rip them off, ohm yourself again. Now you may be closer to 10K.

100K across 120V is a small tingle. 10K across 120V gets into the danger zone.

And those gloves rip VERY easy around sharp metal.

If you ever take 30,000V through your chest, and live, you will become VERY careful how you handle electricals.

It's just like handling poisonous vipers. Except they are invisible. And you die near-instantly.
  • SUPPORTER

GibsonGM

I once tried to 'fix' my parents trash compactor when I was 18.  Lots of junk, cig butts, etc. had gotten away from the bin and into the works.  So ok, I just started digging them out from the side behind the bin, with my finger.   From around the motor.  It was all going good...but then suddenly I was walking around the other side of the room, and didn't know why! 

It took me about 10 minutes to realize that yes, I'd been electrocuted.  A look with a light revealed a  BFC in there...and I had not de-energized the thing first.  Went messing into somewhere not meant for hands.   

That taught me about the things you can't see if you don't have intimate knowledge about a piece of equipment...to always tread slowly and carefully, as if your life depended on it...
  • SUPPORTER
MXR Dist +, TS9/808, Easyvibe, Big Muff Pi, Blues Breaker, Guv'nor.  MOSFace, MOS Boost,  BJT boosts - LPB-2, buffers, Phuncgnosis, FF, Orange Sunshine & others, Bazz Fuss, Tonemender, Little Gem, Orange Squeezer, Ruby Tuby, filters, octaves, trems...

brianq

From someone who's been bit quite a few times, I feel 4 ya! Now u know why they refer 2 it as being bit, never feels good nor do u feel right afterwards( gave me a shiver)

graemestrat

Paul, your hand sweats inside the glove, not outside the glove, so you still have the extra resistance of the rubber in the glove. And yes I have worked on 25kV radar transmitters so I am acutely aware of those risks.

graemestrat

I was watching an electricity company electrician connect a house up to the mains grid by soldering the various cables together. This operation was all done while the cables were live. How did he manage to do that safely??? He was using rubber gloves, sweaty hands and all.

Cozybuilder

#12
I'll take $1000 for electric safety, Alex
And the answer is "To avoid getting zapped with wet hands"
"What is "Why follow Paul's rule for not wearing tearable rubber gloves when working around house electricity?"
Some people drink from the fountain of knowledge, others just gargle.

GibsonGM

Household nitrile gloves are to "electric company gloves" as an ant pushing a rock is to the Saturn V.

The lineman's gloves are made expressly for insulative properties and durability...most any lineman's accident involving touching a conductor with hands involves them NOT wearing the gloves as they should be, or because the glove became damaged, wet, or compromised. 

Do the math with respect to skin resistance wet and dry, and tell me which you'd rather contact voltages greater than 30V with?   I can tell you, as a former environmental technician who had to handle gasoline-soaked soil, rock, and more with those nitriles...they WILL break at the moment you don't want them to...

  • SUPPORTER
MXR Dist +, TS9/808, Easyvibe, Big Muff Pi, Blues Breaker, Guv'nor.  MOSFace, MOS Boost,  BJT boosts - LPB-2, buffers, Phuncgnosis, FF, Orange Sunshine & others, Bazz Fuss, Tonemender, Little Gem, Orange Squeezer, Ruby Tuby, filters, octaves, trems...

graemestrat

If you bothered to read my post you would know that I suggested using the gloves as a final "insurance" that is if you do all the other things I suggested first and then you were still unlucky enough to touch something live then the gloves might lessen the impact of the shock.

I was not, note "not" in any way suggesting that you put the gloves on and proceed to grab everything that was at a high potential.

Geeeeeez, didn't any of you bother to learn to read in school???????

I have really had it with you dumb arses.

antonis

Quote from: graemestrat on July 13, 2017, 01:05:43 AM
your hand sweats inside the glove, not outside the glove, so you still have the extra resistance of the rubber in the glove.
NO rubber glove (not even the classified for surgical use..) is completely waterproof..!!  :icon_wink:

They are manufactured for opposition from out to in (enviroment to hand) according to relative humidity difference..
(their porus orifices are - more or less - conical with their tops placed like reverse biased diodes..)

If you fill a rubber glove with water and hang it in a dry room, you'll be suprised how soon it's outer surface will be "sweated"..
"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

EBK

#16
Quote from: antonis on July 13, 2017, 10:44:46 AM
NO rubber glove (not even the classified for surgical use..) is completely waterproof..!!  :icon_wink:

They are manufactured for opposition from out to in (enviroment to hand) according to relative humidity difference..
(their porus orifices are - more or less - conical with their tops placed like reverse biased diodes..)

If you fill a rubber glove with water and hang it in a dry room, you'll be suprised how soon it's outer surface will be "sweated"..
I know I'd definitely be surprised!
  • SUPPORTER
Technical difficulties.  Please stand by.

GibsonGM

Quote from: graemestrat on July 13, 2017, 09:23:36 AM
If you bothered to read my post you would know that I suggested using the gloves as a final "insurance" that is if you do all the other things I suggested first and then you were still unlucky enough to touch something live then the gloves might lessen the impact of the shock.

I was not, note "not" in any way suggesting that you put the gloves on and proceed to grab everything that was at a high potential.

Geeeeeez, didn't any of you bother to learn to read in school???????

I have really had it with you dumb arses.

Welcome to the forum; good to see you appreciating the advice you're being given here.   Do what you want; after all, YOU'RE the kV man - why are you asking us who "only" mess around with hundreds of volts?

"I have had quite a few shocks lately, while developing some tube amp designs."    Yeah, carry on...sounds like you're "acutely aware" already, are doing things the right way, and really don't need any info whatsoever...
  • SUPPORTER
MXR Dist +, TS9/808, Easyvibe, Big Muff Pi, Blues Breaker, Guv'nor.  MOSFace, MOS Boost,  BJT boosts - LPB-2, buffers, Phuncgnosis, FF, Orange Sunshine & others, Bazz Fuss, Tonemender, Little Gem, Orange Squeezer, Ruby Tuby, filters, octaves, trems...

thermionix

Isn't current at least as much a concern as voltage?  Or rather power?  My last job was at a place that made specialty CRTs (mil/aviation) and I worked with 7~40KV anode voltages daily, though currents were measured in microamps.  Got zapped a few times here and there (it will reach out and get you at those voltages!) but nothing ever felt nearly as serious as 450V from a tube amp.

karbomusic

#19
QuoteIf you ever take 30,000V through your chest, and live, you will become VERY careful how you handle electricals

I took 15k (or whatever made it) through my right arm, down my body to the cement floor when I was 15 - Got too careless with an old 1950s/60s 15k volt neon transformer while burning my name in the floor with a 1" long plasma stream. Not those little 5k ones they have today, but the big ones they used to hang on the building with insulators on the terminals like what you see on a phone pole. Took my breath straight away but it came back, it was a close call.