Circular saw won't ground, safe?

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toller wrote:

You are? Wow! I have worked with other degreed people who were completely clueless. It's still remarkable to me when I meet another. Now do you mean engineer -- or technologist? There is a difference. You might want to see if your old alma matter has a rework dept...

I think that is the debate here.

Did people not dispute at least one thing? I could too -- waste of time. You ignore facts contrary to your experience or opinions.
Post as much as you like -- it's a somewhat free country you live. Movies out for two people cost $30 to $50 -- otoh -- your posts are free and far more entertaining.

Always the helpful one I see.

--
Will
Occasional Techno-geek
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wrote:

fact. Right...
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One fact that you seem to have a little trouble grasping is that you have a lengthy history, both in rec.woodworking and in alt.home.repair, of offering electrical "advice" that is demonstrably incorrect and often dangerous.
Want an example?
About a month ago, over in ahr, somebody was asking about wiring up a range hood, or a stove, I forget which - and you told him to connect the green wire (hint: green = equipment ground) to the circuit *neutral*.
Want another?
A couple days ago, again in ahr, you told a guy to connect both hot legs of an Edison circuit to a single-pole duplex breaker, because you don't know the difference between that, and a double-pole breaker.
You're *dangerous*, toller. Quit trying to answer electrical questions. You don't have the first idea what you're talking about, and you're going to kill somebody some day.
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On Mon, 16 May 2005 14:49:00 +0000, BobS wrote:

There is no apostrophe in the word "always".
--
Rich Grise, Self-Appointed Chief,
Apostrophe Police
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wrote:

Actually, such information is available many places, including the EPRI book on EHV power lines. The 100ma level is about the 0.5% probability level for fibrillation. However, fibrillation is time dependent so that on prolonged contact, the level drops (i.e. at a let-go current of 9-10ma it takes about 10 minutes to cause fibrillation). In many cases, design is based on a 5ma level which is considered at or below the let-go level (not painless) for both adults and children.
--
Don Kelly
snipped-for-privacy@peeshaw.ca
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wrote:

For what contact time is that 0.5% figure for 100a? Or is it just an average figure for all contacts?
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A few problems with this:
1. Perspiration is salty. A sweaty hand on a metal power tool could have resistance down to about 1k ohms or so.
2. Electric shock can stimulate sweat glands.
3. Electric shock at a few 10's of mA or maybe around 10 mA can stimulate muscles and cause you to involuntarily grip what is shocking you.
4. Most sources say 100-1,000 mA is a range of current that is likely to cause ventricular fibrillation, with a few saying this deadly range starts at 50 mA. (Also a few sources make the upper limit of this "most deadly range" lower.) The changes of death do not decrease to zero at 99 or 49 mA. I have heard of electrocution by 30 mA from a neon sign transformer, although people *usually* survive this.
5. Electrocution is unreliable. With electric chairs, they use enough current to either:
* Cook vital organs * Paralyze breathing muscles long enough to deprive the brain of oxygen to the point that breathing will not restart when the shock ends
Lack of electrocution is simularly unreliable.
6. The low fatality rate of 110-120V shocks lulls people into a false sense of security that leads to this voltage achieving a body count. On US Navy ships, most power circuits are 440V rather than 110V, and most electrocution deaths are from 110V. (Another factor could be that lights and ordinary outlets - where exposure to less-trained people is greater than that of 440V stuff - are 110V.) (Yes, US Navy ships have 110V at least nominally rather than 120V.)
- Don Klipstein ( snipped-for-privacy@misty.com)
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Sure is. The problem is that I'm made of 70% salt water
(and no jokes about 30% tequila and lime juice)
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toller wrote:

What colour of flowers would you like at your funeral? Best you let us know now. If you believe that shit, you are going to take a chance some day.
Risks are one thing -- chance is another.
--
Will
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The situation that you described is worse than standing in salt water. If you really had one hand on the Hot and the other on the Neutral, then the current went right through your chest.
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In low voltage the injuries are not usually from the electricity but the secondary reaction. If you are on a ladder and have an electrical induced muscle contraction it can throw you off the ladder killing you when you hit the ground. Likewise if you are holding a screwdriver, you might stab yourself in the eye/brain. (has happened) You could twitch and drill a hole in your leg. If it's an electric chain saw .....Did you ever see a chain saw injury? It gets right to the arteries and you bleed to death fast. So a properly grounded power tool is safer and a GFI plug is better.
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I just get annoyed by the guys warning about the dangers of electrocution.
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<snippage>
properly grounded. I was merely making a comment about the fact that it doesn't have to be a high voltage or high current that can kill you. There are so many variables in an electric shock situation that it is nearly impossible to set a hard & fast rule about what may or may not be fatal.
As Toller said, electricians often get "tingles". Not my idea of how to test a circuit, but I've seen many USN electricians mates test circa WWII shipboard fuse panels(cylindrical fuses on both hot & common) by walking two fingers down the line of fuses. When they get a tingle across one fuse, it's the bad one. Still not my idea of fun.
--
Nahmie
The greatest headaches are those we cause ourselves.
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On Sun, 15 May 2005 12:07:53 -0400, Norman D. Crow wrote:

It's a common myth that a defribrillator (like you see on TeeVee, when they go "CLEAR!" and zap the guy) "jump-starts" the patient's heart. It actually does the opposite. The heart is in fibrillation, and the jolt from the defibrillator causes the heart to cramp up momentarily, stopping the fibrillation. That is, it actually kills the guy. But an otherwise relatively normal heart will restart itself spontaneously, as you've noted.
Cheers! Rich
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Your heart operates on considerably less potential. You're betting that the jolt won't find the proper pathway to interfere or stop it? Foolish wager.
Two in my experience on 120 Volts, but that's 50% of electrocution fatalities I've had.
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On Sun, 15 May 2005 12:08:58 -0400, George wrote:

When I was an electronics tech in the US Air Force, one of the stories that circulated was some guy who killed himself with a PSM-6 VOM. They come with sets of different probes, one of which is needle-sharp. It seems he wanted to measure his body resistance, so he took a probe in each hand and punctured his thumbs. Oh, yeah - on the higher-resistance ranges, that meter uses a 9- or 12-volt battery. Poking through his skin to the wet parts let more than 15 mA go through his heart. I don't know how to find out if this was true or just a scare story. We also were required to take off all rings and watches, and it was strongly recommended to put one hand in your pocket.
There was also the UL about the guy who ohmed out the igniter on an AIM-7 or AIM-9 missile, and the fins cut off both of his hands.
Cheers! Rich
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Rich Grise wrote: ...

Did he then keep one of them in his pocket?
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DUH! *Both* of them!
-- Regards, Doug Miller (alphageek at milmac dot com)
Nobody ever left footprints in the sands of time by sitting on his butt. And who wants to leave buttprints in the sands of time?
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Doug Miller wrote:

But that would have been against the reg's... :)
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Once again demonstrating that you have _no_business_ giving electrical advice to anyone. _Of_course_ it's almost impossible to get a lethal shock under "normal circumstances" because "normal circumstances" don't include doing stupid stuff like putting your hands across a live circuit. It's _abnormal_ circumstances that are dangerous, and it is indeed quite possible to receive a fatal shock from 120V when something has gone wrong - like installing a stove with its equipment ground connected to the circuit neutral conductor, as you recently told someone to do.
And only an idiot would assume that "the other guy" had opened the breaker, and not check first. Hell, I check before touching even when *I* am the guy that opened the breaker - just to make sure I opened the right one.
If you work on your own wiring, I hope you live alone. I'd hate to see anyone else's life jeopardized by your ignorance.
-- Regards, Doug Miller (alphageek at milmac dot com)
Nobody ever left footprints in the sands of time by sitting on his butt. And who wants to leave buttprints in the sands of time?
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