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In article , "K Wind"
writes: "Paul Burridge" wrote in message .. . The question seems daft, but bear with me, gentlemen. Has anyone ever had an electric shock that they feel lucky to have survived? Would 1,500VDC with 6mA capability flowing through one arm and out the other be considered lethal? At one time, I knew how much current was considered lethal, but have forgotten. Think of "30-30" as a mnemonic. If the source has over 30 Volts and can supply over 30 milliamperes through the cardiac region, you will go into cardiac fibrilation. High voltage with little supply current will affect the nerves and the resulting muscle spasms can cause other kinds of injuries, some that may be fatal. DON'T DO IT. PAY ATTENTION! Len Anderson still living in the same reality I was born into... |
In article , "RP Henry" richard.p.henry@saic dot
com writes: "Tom Sevart" wrote in message ... "WB3FUP (Mike Hall)" wrote in message ... 10KV to fire magnetron in counter battery radar. Took six marines to stop me from burying my screw driver in the chest of the asshole that thought it would be cute to push the radiate button. I remember hearing the story of an Air Force tech working on a 30' radar dish. For some dumb reason, someone energized it and promptly microwaved him to death. Some of these stories are hair rasing... and I'm too much of a weenie to stick my tongue on a 9V battery... A Raytheon corporate legend is that one of the engineers discovered the microwave oven principle when a radar melted a chocolate bar in his shirt pocket. That's been an Urban Legend for decades...probably a PR plant from someone at Raytheon's Santa Barbara, CA, division that deveeloped the RadaRange (originally a trademark of Raytheon before they sold that consumer line to Amana). ======== While all the war stories and chit-chat are entertaining, please consider a real-life tragedy that happened to a TV broadcast van in Los Angeles last year. The van had stopped and erected its field-to-transmitter link dish to Mount Wilson where the TV transmitter was. Standard procedure here to get a clear shot above buildings and obstructions, all the field vans have such erectable dishes. Nobody in the field crew seems to have noticed that the van was under a "high-line" of higher-voltage lines common in local area power distribution. The dish and its two-section small crane came in contact with the high-line. Somehow the kind of contact sent a good-sized electrical power flow down into the van. A woman reporter was severely burned in addition to being knocked unconscious...burns severe enough to require amputation of part of an arm and part of a leg. She survived but spent many months in the hospital and physical therapy, had to use a wheelchair to get around even though active and healthy and not yet 40 before the accident. This incident was clearly a result of STUPID NON-ATTENTION by the TV field crew. That high-line distribution is common all over this city and adjoining cities. To erect the link dish right into power wiring of any kind was just compounding the stupidity. I mention this because amateur radio nearly always involves outside antennas in urban areas close to utility power wiring on poles. The possibility of fatal or terrible electric shock isn't confined to some radio-electronic box interior...it exists out in the open, in plain sight. Keep it in mind to avoid frying that mind. Len Anderson retired (and still living) electronic engineer person |
In article , "RP Henry" richard.p.henry@saic dot
com writes: "Tom Sevart" wrote in message ... "WB3FUP (Mike Hall)" wrote in message ... 10KV to fire magnetron in counter battery radar. Took six marines to stop me from burying my screw driver in the chest of the asshole that thought it would be cute to push the radiate button. I remember hearing the story of an Air Force tech working on a 30' radar dish. For some dumb reason, someone energized it and promptly microwaved him to death. Some of these stories are hair rasing... and I'm too much of a weenie to stick my tongue on a 9V battery... A Raytheon corporate legend is that one of the engineers discovered the microwave oven principle when a radar melted a chocolate bar in his shirt pocket. That's been an Urban Legend for decades...probably a PR plant from someone at Raytheon's Santa Barbara, CA, division that deveeloped the RadaRange (originally a trademark of Raytheon before they sold that consumer line to Amana). ======== While all the war stories and chit-chat are entertaining, please consider a real-life tragedy that happened to a TV broadcast van in Los Angeles last year. The van had stopped and erected its field-to-transmitter link dish to Mount Wilson where the TV transmitter was. Standard procedure here to get a clear shot above buildings and obstructions, all the field vans have such erectable dishes. Nobody in the field crew seems to have noticed that the van was under a "high-line" of higher-voltage lines common in local area power distribution. The dish and its two-section small crane came in contact with the high-line. Somehow the kind of contact sent a good-sized electrical power flow down into the van. A woman reporter was severely burned in addition to being knocked unconscious...burns severe enough to require amputation of part of an arm and part of a leg. She survived but spent many months in the hospital and physical therapy, had to use a wheelchair to get around even though active and healthy and not yet 40 before the accident. This incident was clearly a result of STUPID NON-ATTENTION by the TV field crew. That high-line distribution is common all over this city and adjoining cities. To erect the link dish right into power wiring of any kind was just compounding the stupidity. I mention this because amateur radio nearly always involves outside antennas in urban areas close to utility power wiring on poles. The possibility of fatal or terrible electric shock isn't confined to some radio-electronic box interior...it exists out in the open, in plain sight. Keep it in mind to avoid frying that mind. Len Anderson retired (and still living) electronic engineer person |
On Sat, 09 Aug 2003 12:11:19 -0700, Mark Fergerson
wrote: Now that you've explained what you meant, I'll mention that I must be on at least my fifth parallel Universe. Don't bother counting. You have a *lot* more to go, it seems. -- "I believe history will be kind to me, since I intend to write it." - Winston Churchill |
On Sat, 09 Aug 2003 12:11:19 -0700, Mark Fergerson
wrote: Now that you've explained what you meant, I'll mention that I must be on at least my fifth parallel Universe. Don't bother counting. You have a *lot* more to go, it seems. -- "I believe history will be kind to me, since I intend to write it." - Winston Churchill |
Ian White, G3SEK wrote:
. . . An interesting thing happens when you switch off to isolate part of the house wiring, and then cut the "dead" three-wire cable. (We call it "flat twin and earth". It has PVC-insulated hot and neutral wires with a bare ground wire in between, all in a flattish grey or white PVC sheath. Is this what you call "Romex"?) Yes, that's "Romex". The official designation is type NM (for Non-Metallic). 12 gauge wire, for 20 amps maximum, is "12-2 with ground" and 14 gauge, for 15 amps, is "14-2 with ground". Those are the most common sizes for residential lighting and outlet circuits. If you cut the hot and ground wires together, nothing happens; but if you cut the neutral and ground wires together, the RCD trips. That's a puzzle the first time it happens, but it's because that cable isn't quite as "dead" as you think. the isolating switches interrupt only the hot wire, so the neutral and earth are still being shared with everything else that's switched on in the house. Does that happen in the USA, or do you have two-pole isolating switches for individual sub-circuits? I don't quite follow where you're cutting the wires or where the RCD is located. Here, you can get a GFCI as either a circuit breaker you install in the service box to protect a whole circuit, or incorporated in a duplex outlet. Both are easily identifiable by the conspicuous test button. The breaker differs from an ordinary breaker in that the neutral wire is also routed through it. Circuit breakers interrupt only the "hot" wire. It's been a long time since I studied the code (NEC - National Electrical Code), but I'm sure that switching the neutral is still a no-no. Neutral wires are all brought back to the service box, where they're all connected to the central power feed wire. The safety grounds are brought back to the service box separately, where they're connected to the same point as the neutrals. Neutral and safety ground are connected together only at the service box, nowhere else. This isn't totally idle curiosity. If there's an electrical problem while we're staying with the in-laws in Atlanta, I'm the one who's supposed to know about these things... I'd at least get a home-handyman book on electrical wiring, and a real code book if you'll be doing anything other than pretty simple wiring. The rules are quite complex, dictating things like how close to a junction box wires have to be supported, how they can be routed, what size junction box is required for various combinations of entering/exiting wires, etc. In Oregon, wiring can legally be done only by the homeowner or a licensed electrician, but each state and many localities have their own rules. I think all, or just about all, the states now at least have agreed to use the NEC. (You're probably technically forbidden to touch the wiring, depending on Georgia and Atlanta regulations.) The presence of non-code wiring could result in non-payment of insurance if a home were to have an electrical fire. I wired the addition to our home, which involved adding seven circuits including outside outlets and lights. I also replaced and upgraded the service box. Those jobs were done with electrical work permits, and both were inspected and passed. So I have done a bit of this before. But it was a lot of years ago now, the code evolves, and my memory fades. Roy Lewallen, W7EL |
Ian White, G3SEK wrote:
. . . An interesting thing happens when you switch off to isolate part of the house wiring, and then cut the "dead" three-wire cable. (We call it "flat twin and earth". It has PVC-insulated hot and neutral wires with a bare ground wire in between, all in a flattish grey or white PVC sheath. Is this what you call "Romex"?) Yes, that's "Romex". The official designation is type NM (for Non-Metallic). 12 gauge wire, for 20 amps maximum, is "12-2 with ground" and 14 gauge, for 15 amps, is "14-2 with ground". Those are the most common sizes for residential lighting and outlet circuits. If you cut the hot and ground wires together, nothing happens; but if you cut the neutral and ground wires together, the RCD trips. That's a puzzle the first time it happens, but it's because that cable isn't quite as "dead" as you think. the isolating switches interrupt only the hot wire, so the neutral and earth are still being shared with everything else that's switched on in the house. Does that happen in the USA, or do you have two-pole isolating switches for individual sub-circuits? I don't quite follow where you're cutting the wires or where the RCD is located. Here, you can get a GFCI as either a circuit breaker you install in the service box to protect a whole circuit, or incorporated in a duplex outlet. Both are easily identifiable by the conspicuous test button. The breaker differs from an ordinary breaker in that the neutral wire is also routed through it. Circuit breakers interrupt only the "hot" wire. It's been a long time since I studied the code (NEC - National Electrical Code), but I'm sure that switching the neutral is still a no-no. Neutral wires are all brought back to the service box, where they're all connected to the central power feed wire. The safety grounds are brought back to the service box separately, where they're connected to the same point as the neutrals. Neutral and safety ground are connected together only at the service box, nowhere else. This isn't totally idle curiosity. If there's an electrical problem while we're staying with the in-laws in Atlanta, I'm the one who's supposed to know about these things... I'd at least get a home-handyman book on electrical wiring, and a real code book if you'll be doing anything other than pretty simple wiring. The rules are quite complex, dictating things like how close to a junction box wires have to be supported, how they can be routed, what size junction box is required for various combinations of entering/exiting wires, etc. In Oregon, wiring can legally be done only by the homeowner or a licensed electrician, but each state and many localities have their own rules. I think all, or just about all, the states now at least have agreed to use the NEC. (You're probably technically forbidden to touch the wiring, depending on Georgia and Atlanta regulations.) The presence of non-code wiring could result in non-payment of insurance if a home were to have an electrical fire. I wired the addition to our home, which involved adding seven circuits including outside outlets and lights. I also replaced and upgraded the service box. Those jobs were done with electrical work permits, and both were inspected and passed. So I have done a bit of this before. But it was a lot of years ago now, the code evolves, and my memory fades. Roy Lewallen, W7EL |
On Fri, 08 Aug 2003 10:05:43 +0100, Paul Burridge
wrote: On Fri, 08 Aug 2003 03:29:47 GMT, Eric Immel wrote: Paul, are you asking if anyone has been killed, then revived? That's pretty close to what I'm getting at. What I *am* actually get at is that theoretical physicists are coming around to the rather extraordinary view that one cannot from one's own perspective be killed by any sudden and dramatic life event. No matter how bad the shock, you will always 'come around' to find that you've survived. The tricky bit is that you'll probably have found yourself in a different reality to the one you left. In the one you've left, observers will see your cold, dead, smoking body lying sparko on the ground. Your relatives will grieve, your obituary will be written. But *you* won't know anything of that. You'll just believe you've had a lucky escape; you'll go home and tell your friends and family all about it and years later maybe you'll tell others via the Internet. Sounds nuts? Incredible as it may seem, the majority of physicists currently Well that is funky! Got electrocuted pretty well as a teenager. Fiddling about with an ex-Army ZC1 set I'd converted to mains, managed to take 230vac from arm to arm for what seemed like several minutes, but was probably a second. Was sick, shaking, sore and sweaty for a couple of hours, still had sore muscles for several days. Not at all funny. But the universe I came back to seemed pretty normal. Did the NDE thing after drowning in the school pool as a kid though, can pretty clearly recall looking down on myself, and the teacher "bringing me back" I suspect she still wanted to hassle me about the unfinished homework, and drowning was not going to be accepted as an excuse! Still the same universe though! Barry Lennox |
On Fri, 08 Aug 2003 10:05:43 +0100, Paul Burridge
wrote: On Fri, 08 Aug 2003 03:29:47 GMT, Eric Immel wrote: Paul, are you asking if anyone has been killed, then revived? That's pretty close to what I'm getting at. What I *am* actually get at is that theoretical physicists are coming around to the rather extraordinary view that one cannot from one's own perspective be killed by any sudden and dramatic life event. No matter how bad the shock, you will always 'come around' to find that you've survived. The tricky bit is that you'll probably have found yourself in a different reality to the one you left. In the one you've left, observers will see your cold, dead, smoking body lying sparko on the ground. Your relatives will grieve, your obituary will be written. But *you* won't know anything of that. You'll just believe you've had a lucky escape; you'll go home and tell your friends and family all about it and years later maybe you'll tell others via the Internet. Sounds nuts? Incredible as it may seem, the majority of physicists currently Well that is funky! Got electrocuted pretty well as a teenager. Fiddling about with an ex-Army ZC1 set I'd converted to mains, managed to take 230vac from arm to arm for what seemed like several minutes, but was probably a second. Was sick, shaking, sore and sweaty for a couple of hours, still had sore muscles for several days. Not at all funny. But the universe I came back to seemed pretty normal. Did the NDE thing after drowning in the school pool as a kid though, can pretty clearly recall looking down on myself, and the teacher "bringing me back" I suspect she still wanted to hassle me about the unfinished homework, and drowning was not going to be accepted as an excuse! Still the same universe though! Barry Lennox |
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Good point for safety, year or so ago, a new ham lost his life
while putting up an antenna on the roof of a friends home, also a new ham. The antenna contacted house power lines. 73 joe Avery wrote: clipped.... I mention this because amateur radio nearly always involves outside antennas in urban areas close to utility power wiring on poles. The possibility of fatal or terrible electric shock isn't confined to some radio-electronic box interior...it exists out in the open, in plain sight. Keep it in mind to avoid frying that mind. Len Anderson retired (and still living) electronic engineer person |
Good point for safety, year or so ago, a new ham lost his life
while putting up an antenna on the roof of a friends home, also a new ham. The antenna contacted house power lines. 73 joe Avery wrote: clipped.... I mention this because amateur radio nearly always involves outside antennas in urban areas close to utility power wiring on poles. The possibility of fatal or terrible electric shock isn't confined to some radio-electronic box interior...it exists out in the open, in plain sight. Keep it in mind to avoid frying that mind. Len Anderson retired (and still living) electronic engineer person |
hi,
A gfci monitors for a current imbalance between the Hot and Neutral conductors. A ground connection is not necessary. Per NEC 210-7 http://www.leviton.com/sections/techsupp/faq.htm#2 wire gfi Regards. "Gary S." wrote: On Fri, 08 Aug 2003 17:01:16 -0400, Alex wrote: GFCI? Ground Fault Circuit Interruptor. It detects a sudden rise in current to ground and shuts the circuit off in a fraction of a second. Fuses protect the circuit, GFCI protects people. The present US Electrical Code requires them in areas where water is nearby, including bathrooms, kitchens, garages, and outdoors. You are encouraged to use them in other places where there is danger of zapping yourself. They are not a guarantee, but they boost the odds in your favor. |
hi,
A gfci monitors for a current imbalance between the Hot and Neutral conductors. A ground connection is not necessary. Per NEC 210-7 http://www.leviton.com/sections/techsupp/faq.htm#2 wire gfi Regards. "Gary S." wrote: On Fri, 08 Aug 2003 17:01:16 -0400, Alex wrote: GFCI? Ground Fault Circuit Interruptor. It detects a sudden rise in current to ground and shuts the circuit off in a fraction of a second. Fuses protect the circuit, GFCI protects people. The present US Electrical Code requires them in areas where water is nearby, including bathrooms, kitchens, garages, and outdoors. You are encouraged to use them in other places where there is danger of zapping yourself. They are not a guarantee, but they boost the odds in your favor. |
In article , Paul Burridge
writes: On 09 Aug 2003 19:46:02 GMT, (Avery Fineman) wrote: If the source has over 30 Volts and can supply over 30 milliamperes through the cardiac region, you will go into cardiac fibrilation. Sorry, Len, but I can't see it. I routinely check for HV on the anodes of certain smallish valves with bare fingers and can't even begin to feel anything under about 80 volts (at very much more current capability than 30mA) at the low end. However, I read somewhere that some guy died from just a 12V 'shock' - must have been a world record.. :-( I'm not concerned with what YOU do personally, nor will I set any "standards" for all humans based on what one human can or can't do or feel. I got the "30-30" phrase while working at Birtcher Instruments, a semiconductor test instrument maker and a division of Birtcher Medical that made several different medical electronic instruments (EKG, RF knife/cautery, defibrilators,etc.). Someone at Birtcher Medical told me about it. I was Chief Engineer at Birtcher Instruments in Monterey Park, California, a suburb of Los Angeles (not the upstate Monterey, CA, where some FedEx deliveries went, hi). I don't think that my employer at the time would give me false information. The City of Los Angeles building and safety codes don't require inspection of 24 VAC wiring in residences and that sort of wiring is common here for furnace and HVAC controls, doorbells, etc. That AC voltage is never considered "high voltage." That is probably true of the USA National Electrical Code although I haven't read one recently (I've only read the coding in the Numeric Electromagnetic Code recently, quite different from the other "NEC"). I really don't know the medical-biological low threashold for direct cardiac stimulation through an opening in the chest cavity. I don't care to know. I care to know NOT to futz around with my or anyone else's body with anything above the "30-30" limits. If YOU want to experiment with your own body, feel free. Then you transport yourself to that other "reality." When you get there, ask someone there to shock themselves into this reality and tell us all what it is like "over there." I live in THIS reality where survival depends on not treating electricity cavalierly like it was words in a newsgroup. Happy zapping. Len Anderson retired (from regular hours) electronic engineer person |
In article , Paul Burridge
writes: On 09 Aug 2003 19:46:02 GMT, (Avery Fineman) wrote: If the source has over 30 Volts and can supply over 30 milliamperes through the cardiac region, you will go into cardiac fibrilation. Sorry, Len, but I can't see it. I routinely check for HV on the anodes of certain smallish valves with bare fingers and can't even begin to feel anything under about 80 volts (at very much more current capability than 30mA) at the low end. However, I read somewhere that some guy died from just a 12V 'shock' - must have been a world record.. :-( I'm not concerned with what YOU do personally, nor will I set any "standards" for all humans based on what one human can or can't do or feel. I got the "30-30" phrase while working at Birtcher Instruments, a semiconductor test instrument maker and a division of Birtcher Medical that made several different medical electronic instruments (EKG, RF knife/cautery, defibrilators,etc.). Someone at Birtcher Medical told me about it. I was Chief Engineer at Birtcher Instruments in Monterey Park, California, a suburb of Los Angeles (not the upstate Monterey, CA, where some FedEx deliveries went, hi). I don't think that my employer at the time would give me false information. The City of Los Angeles building and safety codes don't require inspection of 24 VAC wiring in residences and that sort of wiring is common here for furnace and HVAC controls, doorbells, etc. That AC voltage is never considered "high voltage." That is probably true of the USA National Electrical Code although I haven't read one recently (I've only read the coding in the Numeric Electromagnetic Code recently, quite different from the other "NEC"). I really don't know the medical-biological low threashold for direct cardiac stimulation through an opening in the chest cavity. I don't care to know. I care to know NOT to futz around with my or anyone else's body with anything above the "30-30" limits. If YOU want to experiment with your own body, feel free. Then you transport yourself to that other "reality." When you get there, ask someone there to shock themselves into this reality and tell us all what it is like "over there." I live in THIS reality where survival depends on not treating electricity cavalierly like it was words in a newsgroup. Happy zapping. Len Anderson retired (from regular hours) electronic engineer person |
I had a NDE when I congratulated a young lady on her pregnancy, and it
turned out she wasn't pregnant. Near-fatal shock, it was, too. Roy Lewallen, W7EL |
I had a NDE when I congratulated a young lady on her pregnancy, and it
turned out she wasn't pregnant. Near-fatal shock, it was, too. Roy Lewallen, W7EL |
Paul Burridge wrote:
On Fri, 08 Aug 2003 21:36:08 GMT, Gary S. Idontwantspam@net wrote: On Fri, 08 Aug 2003 17:01:16 -0400, Alex wrote: GFCI? Ground Fault Circuit Interruptor. How splendid! We call them Residual Current Circuit Breakers in England. Typically they trip out at just over the amount of current required to kill someone. Keeps the bills down that way. In *this* universe, anyway. They're Earth Leakage Detectors in Australia. ;-) Rob |
Paul Burridge wrote:
On Fri, 08 Aug 2003 21:36:08 GMT, Gary S. Idontwantspam@net wrote: On Fri, 08 Aug 2003 17:01:16 -0400, Alex wrote: GFCI? Ground Fault Circuit Interruptor. How splendid! We call them Residual Current Circuit Breakers in England. Typically they trip out at just over the amount of current required to kill someone. Keeps the bills down that way. In *this* universe, anyway. They're Earth Leakage Detectors in Australia. ;-) Rob |
Paul Burridge wrote:
On Fri, 08 Aug 2003 15:52:03 GMT, Spehro Pefhany wrote: Does that mean that my smoking/exploding MOSFETs have narrowly survived their "both sides of the half-bridge on" event in some parallel universe? How about my dog who got runned over (sic) when I was 12? Is he happily chasing various critters somewhere? The world's brightest minds would have it so, strange as it seems. For a gentle introduction into the subject, check out 'The Universe Next Door' by Marcus Chown. Naah. Never was into Science Fantasy ... Rob |
Paul Burridge wrote:
On Fri, 08 Aug 2003 15:52:03 GMT, Spehro Pefhany wrote: Does that mean that my smoking/exploding MOSFETs have narrowly survived their "both sides of the half-bridge on" event in some parallel universe? How about my dog who got runned over (sic) when I was 12? Is he happily chasing various critters somewhere? The world's brightest minds would have it so, strange as it seems. For a gentle introduction into the subject, check out 'The Universe Next Door' by Marcus Chown. Naah. Never was into Science Fantasy ... Rob |
On Sun, 10 Aug 2003 10:30:03 +1200, Barry Lennox
wrote: Still the same universe though! How would you know? -- "I believe history will be kind to me, since I intend to write it." - Winston Churchill |
On Sun, 10 Aug 2003 10:30:03 +1200, Barry Lennox
wrote: Still the same universe though! How would you know? -- "I believe history will be kind to me, since I intend to write it." - Winston Churchill |
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Dave Platt wrote:
Seems to go along well with "keep one hand in your back pocket" and "don't work on this stuff while standing in a puddle of water". When I am around high voltages, I practice the "two-hand rule" - I keep both hands in my pockets and don't touch anything. Blake -- Drop 'pants' to reply by email |
Dave Platt wrote:
Seems to go along well with "keep one hand in your back pocket" and "don't work on this stuff while standing in a puddle of water". When I am around high voltages, I practice the "two-hand rule" - I keep both hands in my pockets and don't touch anything. Blake -- Drop 'pants' to reply by email |
Had big time Electric Shocks -- never fatal obviously
Had big time shocks that should (could) have been fatal -- ART- 13 Dynamotor Navy. 440 AC - steel mill, etc. But tis the current that does you in, not the voltage. Coupla hundred milliAmperes will do it --- URL: http://hypertextbook.com/facts/2000/JackHsu.shtml Guess my Irish hide has lots of ohms! Steel Mill Stories from the 40's (Maybe Urban Legend) 1. A lunch eater sat down and rested his head on a huge copper bus bar (voltage unknown), someone turned on the switch, he was reduced to a frazzled lump with a half a sandwich! 2. A careless electrician up high on an overhead crane, got across a high voltage line and fell into one of those giant ladles that pour out the molten steel. Not found. Maybe the old steel mill hands -- told this to the new guys to scare the hell out of em, Worked for me! Lock the distribution box, take off all jewelry, keep one mitt behind you, keep away from the chassis, -- all good advice, mostly learned the hard way. Then there was a color TV High Voltage supply ---- oocchhh !!! A teeth rattling experience. |
Had big time Electric Shocks -- never fatal obviously
Had big time shocks that should (could) have been fatal -- ART- 13 Dynamotor Navy. 440 AC - steel mill, etc. But tis the current that does you in, not the voltage. Coupla hundred milliAmperes will do it --- URL: http://hypertextbook.com/facts/2000/JackHsu.shtml Guess my Irish hide has lots of ohms! Steel Mill Stories from the 40's (Maybe Urban Legend) 1. A lunch eater sat down and rested his head on a huge copper bus bar (voltage unknown), someone turned on the switch, he was reduced to a frazzled lump with a half a sandwich! 2. A careless electrician up high on an overhead crane, got across a high voltage line and fell into one of those giant ladles that pour out the molten steel. Not found. Maybe the old steel mill hands -- told this to the new guys to scare the hell out of em, Worked for me! Lock the distribution box, take off all jewelry, keep one mitt behind you, keep away from the chassis, -- all good advice, mostly learned the hard way. Then there was a color TV High Voltage supply ---- oocchhh !!! A teeth rattling experience. |
On Sun, 10 Aug 2003 13:06:23 +0100, Paul Burridge
wrote: On 10 Aug 2003 03:22:06 GMT, (Avery Fineman) wrote: I really don't know the medical-biological low threashold for direct cardiac stimulation through an opening in the chest cavity. I don't care to know. I care to know NOT to futz around with my or anyone else's body with anything above the "30-30" limits. As a general safety rule I'm sure you're right. However it does overlook the fact that different individuals have different tolerance levels, hence the fatality at 12V (the only recorded one, I believe) and that Polish electrician who checks for the presence of 230VAC by It also matters what the surface resistance of your skin is, and how good a "connection" to the nervous system and heart. For example, You could put dry fingers on a 9V battery and not feel a thing, but if you lick your fingers first, get a real tingle. Same voltage, but the moisture allows current to flow. In medicine, the defibrillator paddles are covered with a conductive gel, and use a precise pulse of voltage and current. In open heart procedures, lower voltage and current is used, with paddles applied directly to the heart. Of course, disrupting the heart rhythm may happen with lower voltage, especially AC or RF. Why is being careful such a problem for some? Happy trails, Gary (net.yogi.bear) ------------------------------------------------ at the 51st percentile of ursine intelligence Gary D. Schwartz, Needham, MA, USA Please reply to: garyDOTschwartzATpoboxDOTcom |
On Sun, 10 Aug 2003 13:06:23 +0100, Paul Burridge
wrote: On 10 Aug 2003 03:22:06 GMT, (Avery Fineman) wrote: I really don't know the medical-biological low threashold for direct cardiac stimulation through an opening in the chest cavity. I don't care to know. I care to know NOT to futz around with my or anyone else's body with anything above the "30-30" limits. As a general safety rule I'm sure you're right. However it does overlook the fact that different individuals have different tolerance levels, hence the fatality at 12V (the only recorded one, I believe) and that Polish electrician who checks for the presence of 230VAC by It also matters what the surface resistance of your skin is, and how good a "connection" to the nervous system and heart. For example, You could put dry fingers on a 9V battery and not feel a thing, but if you lick your fingers first, get a real tingle. Same voltage, but the moisture allows current to flow. In medicine, the defibrillator paddles are covered with a conductive gel, and use a precise pulse of voltage and current. In open heart procedures, lower voltage and current is used, with paddles applied directly to the heart. Of course, disrupting the heart rhythm may happen with lower voltage, especially AC or RF. Why is being careful such a problem for some? Happy trails, Gary (net.yogi.bear) ------------------------------------------------ at the 51st percentile of ursine intelligence Gary D. Schwartz, Needham, MA, USA Please reply to: garyDOTschwartzATpoboxDOTcom |
On Sun, 10 Aug 2003 09:28:41 -0400, tk wrote:
Years ago (50's) I was sitting on a 240 volt 600 amp circuit breaker inside the Power Distribution Frame of an IBM 704 installed at the Air Force Computing Center in the Pentagon. A civil service operator came in early and hit the power on button...... I survived and so did the operator.... murder is murder.... whatever the reason. The full version of OSHA-approved (the US Occupation Safety and Health Administration of the Department of Labor) safety lock-out/tag-out procedure includes safety procedures such as locking out the electrical power to a piece of equipment while it is being worked on. There is one device applied to the breaker box that locks it off, and then each worker places their own personal padlock to keep that device locked, as well as a supervisor and possibly a safety engineer. The equipment cannot be turned on until every single person is finished and has cleared the area. Seems obsessive, but it doesn't produce stories like on this thread. Happy trails, Gary (net.yogi.bear) ------------------------------------------------ at the 51st percentile of ursine intelligence Gary D. Schwartz, Needham, MA, USA Please reply to: garyDOTschwartzATpoboxDOTcom |
On Sun, 10 Aug 2003 09:28:41 -0400, tk wrote:
Years ago (50's) I was sitting on a 240 volt 600 amp circuit breaker inside the Power Distribution Frame of an IBM 704 installed at the Air Force Computing Center in the Pentagon. A civil service operator came in early and hit the power on button...... I survived and so did the operator.... murder is murder.... whatever the reason. The full version of OSHA-approved (the US Occupation Safety and Health Administration of the Department of Labor) safety lock-out/tag-out procedure includes safety procedures such as locking out the electrical power to a piece of equipment while it is being worked on. There is one device applied to the breaker box that locks it off, and then each worker places their own personal padlock to keep that device locked, as well as a supervisor and possibly a safety engineer. The equipment cannot be turned on until every single person is finished and has cleared the area. Seems obsessive, but it doesn't produce stories like on this thread. Happy trails, Gary (net.yogi.bear) ------------------------------------------------ at the 51st percentile of ursine intelligence Gary D. Schwartz, Needham, MA, USA Please reply to: garyDOTschwartzATpoboxDOTcom |
(Avery Fineman) wrote in message ...
In article , (Bill Bowden) writes: Watson A.Name - 'Watt Sun' wrote in message ... In article , richard.p.henry@saic mentioned... "Tom Sevart" wrote in message ... "WB3FUP (Mike Hall)" wrote in message ... 10KV to fire magnetron in counter battery radar. Took six marines to stop me from burying my screw driver in the chest of the asshole that thought it would be cute to push the radiate button. I remember hearing the story of an Air Force tech working on a 30' radar dish. For some dumb reason, someone energized it and promptly microwaved him to death. Some of these stories are hair rasing... and I'm too much of a weenie to stick my tongue on a 9V battery... A Raytheon corporate legend is that one of the engineers discovered the microwave oven principle when a radar melted a chocolate bar in his shirt pocket. When I was in the army at Ft. Monmouth, NJ, we trained on a radar trainer, had a klystron that put out 1W to the horn on the top of the unit. We could put our finger over the horn and feel it get mildly warm from the RF. Big deal. The Real Thing put our 5 megawatts! Sure, but the pulse width is only a microsecond, so the average power is only 5 watts at one pulse per second. I forget the rep rate of the one I woked on but at 6uS per mile and 400 miles round trip, the rep rate would be about 400 Hz. So it's 400 times 5, or 2KW. -Bill A very rough estimate of "radar range" (time out to return of echo) is 500 feet per microsecond. For a 200 mile search radar the time out to echo return is 2+ milliseconds, depending on whether it is calibrated for statute or nautical miles. Typical PRF for those 200 mile search radars was 400 Hz (PRT of about 2.5 mSec). Average power output is Peak x ((pulse width)/(repetition time)) or 5 MW divided by 2500 = 2 KW. 2 KW concentrated in a 2 to 5 degree cone can have a devastating heating effect on human tissue. One may or may not be "in" the cone of the beam right up close to the feedhorn but, with the construction of most search radars (maritime or ground) there isn't much walk-around space to get away from the feedhorn or the very close in-person effects of microwave radiation. When working on HIGH POWER RF at any frequency, believe in the inverse square law and put as much distance from the antenna as possible...or have a trusted person down on the power controls who keeps the thing OFF while up there doing whatever. I think it would be an interesting subject to compare peak power RF effects versus average power RF effects. I can't seem to find much on that in hundreds of pages of medical-biological reports on the effects of RF radiation on human tissue. Unfortunately, that has been pretty well shunted aside so that someone can get their pet "alternate universe" speculations going on in here. :-) All this gee-whizzy speculation stuff leaves me shocked. But not fatally so... Len Anderson retired (from regular hours) electronic engineer person There are a few refs and calculations in http://arXiv.org/pdf/physics/0102007 Lu, et al (referenced) found that peak power was responsible for spark-gap transmitter injury in rats. Microwave hearing (referenced somewhat; see a review Supplement to Radio Science in 1977) also seems to be because of peak, not average, power. John John Michael Williams |
Some of these stories are hair rasing... and I'm too much of a weenie to stick my tongue on a 9V battery... That's how we tested batteries when I was a kid. 'Course there was the dufus that tried it with a 90v B battery! |
Some of these stories are hair rasing... and I'm too much of a weenie to stick my tongue on a 9V battery... That's how we tested batteries when I was a kid. 'Course there was the dufus that tried it with a 90v B battery! |
"K Wind" wrote in message
.. . Would 1,500VDC with 6mA capability flowing through one arm and out the other be considered lethal? At one time, I knew how much current was considered lethal, but have forgotten. No. It is actually quite hard to kill yourself with electrical shocks. There are tons easier and more likely things to die from in everyday life. 60Hz AC is most dangerous in the range of 100 to 300 mA. Current in that range sometimes causes ventricular fibrillation, whereas currents above that usually cause the heart to temporarily contract and protect itself. Very high currents, however, can dissipate lots of power in your organs and cook them, leading to a painful death if nothing stops the electrocution for several minutes. High frequency AC (like many kilohertz and beyond) should be less dangerous since it will be bound by "skin effect" and not penetrate as far into your chest cavity. DC is considerably safer than 60Hz AC, and I've read some estimates saying you need 4 times as much current to die from DC shocks. I don't know if I believe that though; I suspect there are too few cases to draw significant statistical conclusions. As I understand it (and I may be wrong here), DC is safer than AC because it doesn't cause ventricular fibrillation, so death by these shocks occur from organ damage and falling off ladders and things. Howard Henry Schlunder -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 80,000 Newsgroups - 16 Different Servers! =----- |
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