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  #101  
Old 11-04-2019, 07:07 PM
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Quoth Cooking With Gas:

It's not the volts or amps or watts or hertz that kill you, it's the part where your heart stops beating. That's what kills you.
You mean, where your heart stops beating effectively. One of the two ways that electricity can kill you is by putting the heart into fibrillation, where all of the muscle fibers are marching to the beat of their own drummer. The treatment for which is actually to stop the heart from beating, because usually, when the heart stops beating, it starts back up on its own, and usually in synch. And that's what I was referring to by the hertz killing you, because fibrillation is most likely from frequencies in the range we use for house wiring.

The other way that electricity can kill is by simply cooking you. It's the same effect as if you'd had that much energy dumped into you directly as heat. And that's what I meant by the watts killing you.
  #102  
Old 11-04-2019, 10:01 PM
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Then of course there's arc flash, and maybe the post shock fall that could get you as well.
  #103  
Old 11-05-2019, 03:10 AM
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More specifically it would be the path it travels to ground. If the path is through your heart than either way your done. You can get struck by lightning and live as long as the path to ground doesnt go through any important organs your likely to survive. Also it's more a broad statement so you dont have to explain basic concepts of electricity to someone.
  #104  
Old 11-05-2019, 12:08 PM
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Electric current takes all paths simultaneously.
  #105  
Old 11-06-2019, 01:38 AM
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What is with you people? You don't work on an electrical circuit unless it's de-energized, PERIOD.
Unless you've been TRAINED to do otherwise.
  #106  
Old 11-06-2019, 08:00 AM
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Originally Posted by gogogophers View Post
What is with you people? You don't work on an electrical circuit unless it's de-energized, PERIOD.
Unless you've been TRAINED to do otherwise.
What it is, is a great example of not knowing what you don't know. People work on live circuits all the time because they're being careful not to touch the hot (usually black or red) wire. What they don't know is that an ungrounded box can be hot, a neutral can be hot, things can be miswired and the white wire could be hot and the black neutral.
What I wish is that homeowners that want to do their own electrical work won't invest in a five dollar neon voltage tester and learn how to use it.
With that in hand, you can quickly test to see if power is on, make sure the neutral isn't hot, make sure the ground is good etc.
Not only that, but understanding how to test all those things will quickly ramp up your knowledge of how residential circuits work and make an easy task like swapping an outlet a lot easier, especially if you run into a complication.
  #107  
Old 11-06-2019, 04:29 PM
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Originally Posted by Joey P View Post
What it is, is a great example of not knowing what you don't know. People work on live circuits all the time because they're being careful not to touch the hot (usually black or red) wire. What they don't know is that an ungrounded box can be hot, a neutral can be hot, things can be miswired and the white wire could be hot and the black neutral.
What I wish is that homeowners that want to do their own electrical work won't invest in a five dollar neon voltage tester and learn how to use it.
With that in hand, you can quickly test to see if power is on, make sure the neutral isn't hot, make sure the ground is good etc.
Not only that, but understanding how to test all those things will quickly ramp up your knowledge of how residential circuits work and make an easy task like swapping an outlet a lot easier, especially if you run into a complication.
It's easy.
Don't f*** with s*** you don't know anything about, especially if it's potentially lethal.
The time for this education is prior to the action of goofing around with wires... especially hot.

After 44 years of experience with such, I can say it's a terrible idea to advance the notion of a homeowner hotwiring anything. There are so many variables involved in hotwiring that can result in injury, it's not worth the risk to an improperly trained person.

Yeah, there are the goofballs here that claim that 120 volts just "tingle" and can't hurt you, and that one can "safely" handle a hot wire while not touching a grounded wire. This is all bullshit, depending on circumstance. The "circumstances" are infinitely variable... just like Russian roulette... simply take your chance.

I'd rather just kill the power and be safe. It's not that difficult. Any competent electrician with a circuit-seeker can isolate the appropriate circuit (breaker) to minimize the inconvenience.
So are you willing to bet your life on it?
  #108  
Old 11-06-2019, 06:12 PM
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I am reminded of the first dead person I ever saw at age 16 or so. I was at a boarding school and the corpse was an electrician who had been asked to fix a faulty overhead incandescent light.

The ceiling was too high for him to reach so he dragged a handy chair over and took the bulb out. (Most of this is assumption because he could not tell anyone why he put his fingers in a live socket). Before putting a new bulb in, he wanted to test the socket to see if it was live, so he put a finger in. I understand that this was quite normal practice and he was wearing rubber-soled boots, so any shock would normally have been minor.

Unfortunately for him, he hadn't noticed that the cement floor was damp, the chair he was standing on had a metal frame, and that he was holding the back of it for balance. 240 volts from one hand to the other proved to be fatal.

Last edited by bob++; 11-06-2019 at 06:12 PM.
  #109  
Old 11-06-2019, 07:23 PM
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Amen.
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Don't ask me to explain others' notions...
I can barely justify my own.
  #110  
Old 11-06-2019, 07:52 PM
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Originally Posted by gogogophers View Post
It's easy.
Don't f*** with s*** you don't know anything about, especially if it's potentially lethal.
The time for this education is prior to the action of goofing around with wires... especially hot.
I wouldn't suggest it either, all I'm saying is that if you don't know how dangerous it is or the unexpected pitfalls, well, you don't know.

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Originally Posted by bob++ View Post
The ceiling was too high for him to reach so he dragged a handy chair over and took the bulb out. (Most of this is assumption because he could not tell anyone why he put his fingers in a live socket). Before putting a new bulb in, he wanted to test the socket to see if it was live, so he put a finger in. I understand that this was quite normal practice and he was wearing rubber-soled boots, so any shock would normally have been minor.
Did he actually stick his finger in it to test it? I would have figured that the socket was wired backwards so the threads were hot instead of neutral and if he had his finger on the metal part of the bulb while threading it in, that would have done it.

Quote:
Unfortunately for him, he hadn't noticed that the cement floor was damp, the chair he was standing on had a metal frame, and that he was holding the back of it for balance. 240 volts from one hand to the other proved to be fatal.
240? [checks location] ok, got it.

An old plumber's trick is to keep one hand in your pocket while doing electrical work for exactly that reason. Plumber's specifically because it's tempting to hold on to the metal drain or copper supply while you're leaning under the sink.
  #111  
Old 11-06-2019, 08:24 PM
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Originally Posted by Joey P View Post
I wouldn't suggest it either, all I'm saying is that if you don't know how dangerous it is or the unexpected pitfalls, well, you don't know.
Precisely to the point. Electrical wiring isn't something to be fumbled through, learning as you go as say, fixing a leaky faucet.
  #112  
Old 11-06-2019, 08:32 PM
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Quote:
Originally Posted by Joey P
Did he actually stick his finger in it to test it? I would have figured that the socket was wired backwards so the threads were hot instead of neutral and if he had his finger on the metal part of the bulb while threading it in, that would have done it.
My grandfather was known for sticking his thumb into a light socket to tell if it was a burned out bulb or the less-than-reliable wiring of that era causing unwanted darkness. Apparently he had a substantial callus on his thumb, so touching hot gave only a small tingle.
  #113  
Old 11-06-2019, 08:45 PM
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Ya know, I've been in the biz for the previously mentioned 44 years and have been regaled with all kinds of tales related to such machismo nonsense from day one, yet never have I witnessed any electrician actually perform such a feat. Go figure
  #114  
Old 11-06-2019, 09:30 PM
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Originally Posted by Joey P View Post
An old plumber's trick is to keep one hand in your pocket while doing electrical work for exactly that reason. Plumber's specifically because it's tempting to hold on to the metal drain or copper supply while you're leaning under the sink.
I don't know any plumbers that do electrical work, but irrespectively, how does one perform an electrical task one handed, with their off hand stuck in their pocket while under a sink?
  #115  
Old 11-07-2019, 12:00 AM
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Originally Posted by gotpasswords View Post
My grandfather was known for sticking his thumb into a light socket to tell if it was a burned out bulb or the less-than-reliable wiring of that era causing unwanted darkness. Apparently he had a substantial callus on his thumb, so touching hot gave only a small tingle.
My grandfather would use a lighter to find gas leaks. In the majority of situations, it probably won't do much other than blow the flame out, but I'd still prefer to use bubbles.

Quote:
Originally Posted by gogogophers View Post
I don't know any plumbers that do electrical work, but irrespectively, how does one perform an electrical task one handed, with their off hand stuck in their pocket while under a sink?
Plumbers, while not doing major electrical work, still connect and troubleshoot dishwashers, ice makers, garbage disposals etc.
Also, the 'one hand rule' is an actual thing. Some places actually require their employees to keep one hand in their pocket or behind their back when working on live equipment. Granted, if you're fixing or replacing something you'll need two hands and a dead circuit, but often you need everything energized to do the actual testing. For example, if the disposal doesn't turn on when you flip the switch you need everything to be live when to find out if it's getting power and/or where the problem is.
And, just to get it out of the way, in some (many?) jurisdictions, a tradesman is allowed to do minor electrical work like making the final connection or working on the wiring within the equipment they're working on.

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Originally Posted by DesertDog View Post
Yet under the right circumstances, less than 50 volts can allow enough current to do the job. Even zombie volts.
I could be wrong here, but on the assumption that by zombie volts you're talking about showing a voltage on a circuit that's actually induced by nearby wires, I was under the impression that it carries no amperage. I've had issues tracking down problems with equipment and running into wires that are showing somewhere in the 20-60 volt range. I believe some electricians will connect something to the circuit (like a light bulb) to drive the voltage back to zero (assuming it's dead). If they have one, they can also use a low impedance DMM to place a load on the circuit.
  #116  
Old 11-07-2019, 12:18 AM
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When changing live outlets (from 2 prong to three prong) I made it a point to NOT touch anything. I used exclusively pliers with insulated grips and screwdrivers (which always have insulated handles). I know enough about electricity to know that if my fingers are in there anywhere, there's a chance they will slip and touch the wrong thing(s). I sure as heck would not work on a live circuit breaker panel itself. And changing outlets, I did blow up two of the 20 or so when I touched the metal box pushing them back in, since with pliers you have a bit less control but a lot more personal safety. If the boxes or ground ended up live, some sort of poof or breaker blowing would be the result pretty quick, unless the circuit breaker panel was extremely incompetently wired.
  #117  
Old 11-07-2019, 12:38 AM
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Originally Posted by TheBori View Post
Now, 220v (for our European friends) will take you off a ladder.
Which is, if not the most common, then is at least one of the more common ways for an electric shock to kill you in Aus (240V). Ladders are dangerous....

But the Father of my boss at work was a HV electrician. 22KV etc. He didn't regard 240V as dangerous -- more like being frightened of the dark.

Last edited by Melbourne; 11-07-2019 at 12:39 AM.
  #118  
Old 11-07-2019, 12:57 AM
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Originally Posted by Melbourne View Post
Which is, if not the most common, then is at least one of the more common ways for an electric shock to kill you in Aus (240V). Ladders are dangerous....

But the Father of my boss at work was a HV electrician. 22KV etc. He didn't regard 240V as dangerous -- more like being frightened of the dark.
An experienced electrician friend said that he considered 240V the most dangerous. Because 120V is low enough that you can generally let go, thus breaking the circuit. And 480V is strong enough to usually throw you across the room (breaking the circuit). But 240V often paralyses people, so they can't let go of the live wire. So they get shocked longer, with more chance of injury/death.

And if a bystander tries to grab them and pull them loose, the bystander also gets shocked & can't let go. He said that when doing industrial wiring, they always worked in pairs and kept a non-conductive pole (wood or plastic) handy, to use to safely break the circuit.
  #119  
Old 11-07-2019, 08:59 AM
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Originally Posted by Joey P View Post
I could be wrong here, but on the assumption that by zombie volts you're talking about showing a voltage on a circuit that's actually induced by nearby wires, I was under the impression that it carries no amperage.
I was talking about the point that the last post previous to Sirjosehime's was nine years ago.
  #120  
Old 11-07-2019, 09:24 AM
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Originally Posted by Melbourne View Post
Which is, if not the most common, then is at least one of the more common ways for an electric shock to kill you in Aus (240V). Ladders are dangerous....

But the Father of my boss at work was a HV electrician. 22KV etc. He didn't regard 240V as dangerous -- more like being frightened of the dark.
I used to work on a military base, and I was chatting with the base electricians one day about working with electricity, as they work with both high voltage (12kV and up) and house wiring (120V). I mentioned that I figured they'd have more accidents with guys moving from working on 120V stuff to 12kV stuff as there's a lot more voltage, but they told me it's the opposite. They see more accidents with the guys who go from 12kV to 120V as they are complacent ("I've handled 12,000 volt stuff! 120V is nothing.") and get fried. The guys who move up to 12kV are scared of getting electrocuted, and so don't shortcut safety.
  #121  
Old 11-07-2019, 07:33 PM
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Originally Posted by Patch View Post
I used to work on a military base, and I was chatting with the base electricians one day about working with electricity, as they work with both high voltage (12kV and up) and house wiring (120V). I mentioned that I figured they'd have more accidents with guys moving from working on 120V stuff to 12kV stuff as there's a lot more voltage, but they told me it's the opposite. They see more accidents with the guys who go from 12kV to 120V as they are complacent ("I've handled 12,000 volt stuff! 120V is nothing.") and get fried. The guys who move up to 12kV are scared of getting electrocuted, and so don't shortcut safety.
Industry, too, and this is so much the truth. No one (for the most part) dies in the substation.
  #122  
Old 11-07-2019, 07:58 PM
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Back when I was working as an electrician's assistant, I learned that you should always have at least three points of safety: That is to say, three separate precautions, any one of which, if it works properly, should be enough to guarantee safety. So, for instance, you switch off the breaker, and use one hand at a time, and use insulated tools. Or if one of those isn't practical, you add another one (rubber gloves, maybe). That way, if any one, or even two, points of safety fail, you're still safe.
  #123  
Old 11-08-2019, 01:51 PM
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I grabbed an energized 345KV line with my bare hands!

It's true. I had the opportunity to visit an AB Chance lab.
Wearing a Faraday suit I was to climb a 12 foot fiberglass ladder while holding a fiberglass stick which held a hook that ran along a cable to my Faraday suit.

Once close enough to the line (it was 15 feet off the ground, inside a laboratory) I used the stick to connect my tail and energize my suit.

Climbed up three more steps and grabbed the conductor with my right hand.
Just for fun I gave it a kiss.

I was the human equivalent to a bird sitting on a wire.

The Faraday suit was for protection from the line's EMF field. If I wasn't wearing the suit I would have currents running through my body based on my feet being further away from the conductor than my hand.

The Faraday suit was like an elastic jump suit. The legging section fit around my ankles. Since right below my ankles was uncovered I could feel corona discharge there. It felt like a 70 MPH wind was blowing against my feet.
  #124  
Old 11-08-2019, 02:43 PM
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Originally Posted by Tim@T-Bonham.net View Post
An experienced electrician friend said that he considered 240V the most dangerous. Because 120V is low enough that you can generally let go, thus breaking the circuit. And 480V is strong enough to usually throw you across the room (breaking the circuit). But 240V often paralyses people, so they can't let go of the live wire. So they get shocked longer, with more chance of injury/death.
What also factors into it (and is probably a more significant factor than muscle paralysis) is how much current flows across the heart. At lower voltages, you don't get enough current to reliably throw your heart into fibrillation. As the current increases, the heart is more reliably thrown into fibrillation, so the fatality rate rises. Your heart has kind of a weird design in that the fibrillation state is stable. In other words, if you can get your heart into fibrillation, it won't get out of that state on its own. This is why you need a defibrillator.

At higher voltages and currents though, a funny thing happens. Instead of the electricity just screwing up your heartbeat and throwing the heart into fibrillation, all of the heart muscles tend to just clamp. I should probably point out that in this state the heart is still not pumping blood, so if you don't somehow get removed from the source of the current you're still toast. But unlike the fibrillation state, once your heart comes out of this muscle clamp, it generally tends to go back into a normal rhythm all by itself.

And then at even higher voltage and current levels, the electricity just cooks you to death.

So it's kinda weird that if you start at zero and increase the current, electricity generally gets more and more dangerous, but then the fatality rate decreases once you get to the point where your heart muscles clamp, and then the fatality rate increases again with the current once you get past that.

Quote:
Originally Posted by Patch View Post
I used to work on a military base, and I was chatting with the base electricians one day about working with electricity, as they work with both high voltage (12kV and up) and house wiring (120V). I mentioned that I figured they'd have more accidents with guys moving from working on 120V stuff to 12kV stuff as there's a lot more voltage, but they told me it's the opposite. They see more accidents with the guys who go from 12kV to 120V as they are complacent ("I've handled 12,000 volt stuff! 120V is nothing.") and get fried. The guys who move up to 12kV are scared of getting electrocuted, and so don't shortcut safety.
I design industrial controls for a living, and I'll add a "me too" to this. I don't think anything of climbing into an area or poking around in a cabinet as long as it's all 240 volts or less. I don't just blindly walk up and touch exposed contacts or anything quite that stupid, but I really don't get as concerned as I probably should about safety until the voltage gets to 480 and above.

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Originally Posted by BubbaDog View Post
I grabbed an energized 345KV line with my bare hands!
Um... yeah. No thanks. I'll stay way over here in the control room while you go ahead and do stuff like that. No, I don't care if you're offering me a Faraday suit. I don't wanna.

At those kinds of voltages you have to be careful about pointing at anything because your fingertip might draw an arc.
  #125  
Old 11-08-2019, 04:14 PM
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So, where do we all stand on using those V-belt tensioning tools while the engine is running? Or adding a new plumbing line with the pressure on?
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