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Sorry for the slow response but the Internet connection to the "other
side" is soooooooo slow! Yes, I have had a a fatal electric shock in the past. Yours truly, William Kemmler |
Sorry for the slow response but the Internet connection to the "other
side" is soooooooo slow! Yes, I have had a a fatal electric shock in the past. Yours truly, William Kemmler |
In article ,
mentioned... On Sat, 9 Aug 2003 01:18:38 +1000, "Alex Gibson" wrote: From my own experiance, rf burns hurt more than standard 50Hz ac or dc shocks even though I would have to rate car iginition systems a close second. I think I may have experienced rf burns some years ago. Is this when you touch a metal object close to an rf field; it feels thermally *hot* enough to burn you, but when the field is killed, said object *instantly* feels normal room temperature again? No, RF burns is when the skin is actually burnt. -- -- @@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@ h@e@r@e@@ ###Got a Question about ELECTRONICS? Check HERE First:### http://users.pandora.be/educypedia/e...s/databank.htm My email address is whitelisted. *All* email sent to it goes directly to the trash unless you add NOSPAM in the Subject: line with other stuff. alondra101 at hotmail.com Don't be ripped off by the big book dealers. Go to the URL that will give you a choice and save you money(up to half). http://www.everybookstore.com You'll be glad you did! Just when you thought you had all this figured out, the gov't changed it: http://physics.nist.gov/cuu/Units/binary.html @@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@ u@e@n@t@@ |
"Watson A.Name - 'Watt Sun'" wrote: In article , mentioned... A former member of the Air Force told me about a safety training video narrated by a transmitter tech who did not observe *all* the procedures. He survived to make the video, but as a double amputee. I was told that this training video was part of the curriculum for so many years that the principal character became somewhat of a celebrity. Perhaps someone with more direct knowledge can add or correct the details. Tom, N3IJ Well, that's a helluva way to become a celebrity! But on observation, the amputee must've been a DOD civilian, because he couldn't have remained in the AF without his legs. Or whatever was amputated. Or maybe he did the narration after he had recovered and was discharged. I wouldn't count on it. My Brother-in-Law lost a leg while in the airforce and served more than 20 years after that before he retired, picked up quite a few promotions along the way. I think you will find that amputees have served in the USAF, RAF, RCAF, RCN and probably several other military services over the years. Admittedly they lost their limbs after they joined the service. From what I can recall one USAF aircrew member lost a limb in a (B-47)? crash, the RCN guy lost one after his aircraft went off a carrier and he passed under the carrier and lost, I think a leg. The most famous is probably Douglas Bader who lost both legs and went on to serve as a fighter pilot in WWII. One thing they all have in common is that they fought like hell to stay in. Dave |
"Watson A.Name - 'Watt Sun'" wrote: In article , mentioned... A former member of the Air Force told me about a safety training video narrated by a transmitter tech who did not observe *all* the procedures. He survived to make the video, but as a double amputee. I was told that this training video was part of the curriculum for so many years that the principal character became somewhat of a celebrity. Perhaps someone with more direct knowledge can add or correct the details. Tom, N3IJ Well, that's a helluva way to become a celebrity! But on observation, the amputee must've been a DOD civilian, because he couldn't have remained in the AF without his legs. Or whatever was amputated. Or maybe he did the narration after he had recovered and was discharged. I wouldn't count on it. My Brother-in-Law lost a leg while in the airforce and served more than 20 years after that before he retired, picked up quite a few promotions along the way. I think you will find that amputees have served in the USAF, RAF, RCAF, RCN and probably several other military services over the years. Admittedly they lost their limbs after they joined the service. From what I can recall one USAF aircrew member lost a limb in a (B-47)? crash, the RCN guy lost one after his aircraft went off a carrier and he passed under the carrier and lost, I think a leg. The most famous is probably Douglas Bader who lost both legs and went on to serve as a fighter pilot in WWII. One thing they all have in common is that they fought like hell to stay in. Dave |
"Watson A.Name - 'Watt Sun'" wrote in message .. . In article , mentioned... Paul Burridge wrote: On Thu, 07 Aug 2003 12:33:24 GMT, "Harris" wrote: Several people have and of course they are all dead. Well I don't believe the answer's that simple. I'll explain in due Yes it is. 'Fatal' doesn't have any slack in its definition. You could modify it by adding 'near' as a prefix. I agree. He said one thing, but meant another. Snot what you think! Answer this question: Q: Twenty years ago, a plane is flying at 20,000 feet over Germany. If you will recall, Germany at the time was politically divided into West Germany and East Germany. Anyway, during the flight, TWO of the engines fail. The pilot, realizing that the last remaining engine is also failing, decides on a crash landing. Unfortunately, the engine fails before he has time and the plane crashes smack in the middle of "no-man's-land" between East Germany and West Germany. Where would you bury the survivors - East Germany or West Germany or in "no-man's- land?" Land in no-man's-land and they might be, burying the SURVIVORS.... at that time. Jeff DOH! For the answer, and other similar Qs, see http://dailyfunnies.org/archives/000637.html -- @@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@ h@e@r@e@@ ###Got a Question about ELECTRONICS? Check HERE First:### http://users.pandora.be/educypedia/e...s/databank.htm My email address is whitelisted. *All* email sent to it goes directly to the trash unless you add NOSPAM in the Subject: line with other stuff. alondra101 at hotmail.com Don't be ripped off by the big book dealers. Go to the URL that will give you a choice and save you money(up to half). http://www.everybookstore.com You'll be glad you did! Just when you thought you had all this figured out, the gov't changed it: http://physics.nist.gov/cuu/Units/binary.html @@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@ u@e@n@t@@ |
"Watson A.Name - 'Watt Sun'" wrote in message .. . In article , mentioned... Paul Burridge wrote: On Thu, 07 Aug 2003 12:33:24 GMT, "Harris" wrote: Several people have and of course they are all dead. Well I don't believe the answer's that simple. I'll explain in due Yes it is. 'Fatal' doesn't have any slack in its definition. You could modify it by adding 'near' as a prefix. I agree. He said one thing, but meant another. Snot what you think! Answer this question: Q: Twenty years ago, a plane is flying at 20,000 feet over Germany. If you will recall, Germany at the time was politically divided into West Germany and East Germany. Anyway, during the flight, TWO of the engines fail. The pilot, realizing that the last remaining engine is also failing, decides on a crash landing. Unfortunately, the engine fails before he has time and the plane crashes smack in the middle of "no-man's-land" between East Germany and West Germany. Where would you bury the survivors - East Germany or West Germany or in "no-man's- land?" Land in no-man's-land and they might be, burying the SURVIVORS.... at that time. Jeff DOH! For the answer, and other similar Qs, see http://dailyfunnies.org/archives/000637.html -- @@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@ h@e@r@e@@ ###Got a Question about ELECTRONICS? Check HERE First:### http://users.pandora.be/educypedia/e...s/databank.htm My email address is whitelisted. *All* email sent to it goes directly to the trash unless you add NOSPAM in the Subject: line with other stuff. alondra101 at hotmail.com Don't be ripped off by the big book dealers. Go to the URL that will give you a choice and save you money(up to half). http://www.everybookstore.com You'll be glad you did! Just when you thought you had all this figured out, the gov't changed it: http://physics.nist.gov/cuu/Units/binary.html @@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@ u@e@n@t@@ |
Paul Burridge wrote:
The question seems daft, but bear with me, gentlemen. Has anyone ever had an electric shock that they feel lucky to have survived? p. -- "I believe history will be kind to me, since I intend to write it." - Winston Churchill Nothing like that, yet. Rewired some factory emergency lights and replaced several more, one leg of a 480V circuit, live. Work careful and no problems. Removing a high-pressure bulb from a high-voltage circuit, glass envelope broke in my hand while trying to unscrew it, didn't know I could move that fast. Rewiring a conveyor, co-worker said the power was off, sparks flew when I cut the cable. I just stared at the remains of my pliers and then at him. ONE HAND in contact with the work, nothing else, work on insulated surface, heavy rubber sole boots, and anything else I can think of. Worked at one plant that had had a color blind electrician, that really taught me caution, never knew what color wired carried what voltage. |
Paul Burridge wrote:
The question seems daft, but bear with me, gentlemen. Has anyone ever had an electric shock that they feel lucky to have survived? p. -- "I believe history will be kind to me, since I intend to write it." - Winston Churchill Nothing like that, yet. Rewired some factory emergency lights and replaced several more, one leg of a 480V circuit, live. Work careful and no problems. Removing a high-pressure bulb from a high-voltage circuit, glass envelope broke in my hand while trying to unscrew it, didn't know I could move that fast. Rewiring a conveyor, co-worker said the power was off, sparks flew when I cut the cable. I just stared at the remains of my pliers and then at him. ONE HAND in contact with the work, nothing else, work on insulated surface, heavy rubber sole boots, and anything else I can think of. Worked at one plant that had had a color blind electrician, that really taught me caution, never knew what color wired carried what voltage. |
"Bob Yates" wrote in message ... Rewiring a conveyor, co-worker said the power was off, sparks flew when I cut the cable. I just stared at the remains of my pliers and then at him. ONE HAND in contact with the work, nothing else, work on insulated surface, heavy rubber sole boots, and anything else I can think of. I worked college summers as an electrician. Cut a live lamp circuit with my brand new pliers, leaving a 14-ga notch. Years later, I saw "my" pliers in the lab tech's toolbox. He said he had done the same thing a few years back. I didn't really believe they were his until I found my old pliers in the bottom of my garage toolkit. |
"Bob Yates" wrote in message ... Rewiring a conveyor, co-worker said the power was off, sparks flew when I cut the cable. I just stared at the remains of my pliers and then at him. ONE HAND in contact with the work, nothing else, work on insulated surface, heavy rubber sole boots, and anything else I can think of. I worked college summers as an electrician. Cut a live lamp circuit with my brand new pliers, leaving a 14-ga notch. Years later, I saw "my" pliers in the lab tech's toolbox. He said he had done the same thing a few years back. I didn't really believe they were his until I found my old pliers in the bottom of my garage toolkit. |
Chris1 wrote:
In article , "Michael A. Terrell" wrote: I find that very interesting, since every chocolate bar I have ever had was wrapped in aluminum foil. I always thought it was just shiny paper. There's not much Aluminum there, if any. Chris A very thin aluminum foil, with a paper backing. Use an Ohm meter on a piece to see that it is conductive. -- Its August 5, 2003, so I'm 51 today! Michael A. Terrell Central Florida |
Chris1 wrote:
In article , "Michael A. Terrell" wrote: I find that very interesting, since every chocolate bar I have ever had was wrapped in aluminum foil. I always thought it was just shiny paper. There's not much Aluminum there, if any. Chris A very thin aluminum foil, with a paper backing. Use an Ohm meter on a piece to see that it is conductive. -- Its August 5, 2003, so I'm 51 today! Michael A. Terrell Central Florida |
Eric in the Evening wrote:
Hey Charles, When I was a "frameman" (oops, make that "frame attendant") in the Alameda Central Office, had exactly the same type of "shock". Air conditioning had broken, we were in t-shirts, about 90+ degrees in the CO on a summers day and sweating. Reaching through the frame from the equipment side hit someone who was ringing and became a human bell clapper for about 20-30 seconds. All this at the top of a rolling ladder. My fellow employees and myself got a laugh out of it (me later). Actually happened a few times over my 27 year career. At least I'm not unique in that sense. Thanks for sharing...... Eric KA6USJ Eric, In my days as a Frame Ape, I got across one of the Darned Gov't special circuits that had a lot more than ring voltage on it. Only once though, I can still remember the special warning tags they hadon the lines at all the blocks, and like you Iwas at the top of the ladder when it happened. And oh yes I also got bit by ring more than once. Remember the way we found shorts? Bill Higdon |
Eric in the Evening wrote:
Hey Charles, When I was a "frameman" (oops, make that "frame attendant") in the Alameda Central Office, had exactly the same type of "shock". Air conditioning had broken, we were in t-shirts, about 90+ degrees in the CO on a summers day and sweating. Reaching through the frame from the equipment side hit someone who was ringing and became a human bell clapper for about 20-30 seconds. All this at the top of a rolling ladder. My fellow employees and myself got a laugh out of it (me later). Actually happened a few times over my 27 year career. At least I'm not unique in that sense. Thanks for sharing...... Eric KA6USJ Eric, In my days as a Frame Ape, I got across one of the Darned Gov't special circuits that had a lot more than ring voltage on it. Only once though, I can still remember the special warning tags they hadon the lines at all the blocks, and like you Iwas at the top of the ladder when it happened. And oh yes I also got bit by ring more than once. Remember the way we found shorts? Bill Higdon |
Paul Burridge wrote:
Ground Fault Circuit Interruptor. How splendid! We call them Residual Current Circuit Breakers in England. That may not be an accurate translation. As I understand it, the GFCI requires a ground connection in order to operate, while the RCB does not. The RCB functions on the difference between the outgoing 'live' current and the return current in the neutral. In the British house wiring system, those two currents should be *exactly* equal, and the difference (the 'residual current') should be zero. Any difference at all means something's wrong - ping - you're disconnected. A typical household RCB will trip on a 60 or 100mA difference in supply current surges up to 60A. That's pretty good common-mode rejection! RCDs can also be cascaded, so an even more sensitive RCD can be used to protect an outdoor mains socket or a workbench. We used to have something like GFCIs over here, but changed to RCDs because RCDs still work if the entire house ground connection has failed. -- 73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB) Editor, 'The VHF/UHF DX Book' http://www.ifwtech.co.uk/g3sek |
Paul Burridge wrote:
Ground Fault Circuit Interruptor. How splendid! We call them Residual Current Circuit Breakers in England. That may not be an accurate translation. As I understand it, the GFCI requires a ground connection in order to operate, while the RCB does not. The RCB functions on the difference between the outgoing 'live' current and the return current in the neutral. In the British house wiring system, those two currents should be *exactly* equal, and the difference (the 'residual current') should be zero. Any difference at all means something's wrong - ping - you're disconnected. A typical household RCB will trip on a 60 or 100mA difference in supply current surges up to 60A. That's pretty good common-mode rejection! RCDs can also be cascaded, so an even more sensitive RCD can be used to protect an outdoor mains socket or a workbench. We used to have something like GFCIs over here, but changed to RCDs because RCDs still work if the entire house ground connection has failed. -- 73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB) Editor, 'The VHF/UHF DX Book' http://www.ifwtech.co.uk/g3sek |
On Thu, 07 Aug 2003 11:29:46 +0100, Paul Burridge
wrote: The question seems daft, but bear with me, gentlemen. Has anyone ever had an electric shock that they feel lucky to have survived? p. This guy did believe it or not. http://www.electrical-contractor.net/electrocution.htm -- Regards, Boris Mohar Got Knock? - see: Viatrack Printed Circuit Designs http://www3.sympatico.ca/borism/ Aurora, Ontario |
On Thu, 07 Aug 2003 11:29:46 +0100, Paul Burridge
wrote: The question seems daft, but bear with me, gentlemen. Has anyone ever had an electric shock that they feel lucky to have survived? p. This guy did believe it or not. http://www.electrical-contractor.net/electrocution.htm -- Regards, Boris Mohar Got Knock? - see: Viatrack Printed Circuit Designs http://www3.sympatico.ca/borism/ Aurora, Ontario |
On Sat, 9 Aug 2003 09:01:05 +0100, "Ian White, G3SEK"
wrote: A typical household RCB will trip on a 60 or 100mA difference in supply current surges up to 60A. That's pretty good common-mode rejection! It's better than that. 30mA is the standard currently. -- "I believe history will be kind to me, since I intend to write it." - Winston Churchill |
On Sat, 9 Aug 2003 09:01:05 +0100, "Ian White, G3SEK"
wrote: A typical household RCB will trip on a 60 or 100mA difference in supply current surges up to 60A. That's pretty good common-mode rejection! It's better than that. 30mA is the standard currently. -- "I believe history will be kind to me, since I intend to write it." - Winston Churchill |
On Sat, 09 Aug 2003 00:15:15 GMT, Gary S. Idontwantspam@net wrote:
The example above sounds more like inductive heating. If an ungrounded piece of metal is near an RF energized coil, a current is induced in it which heats it up. Somewhat similar to a microwave oven. I don't see how it can be. The metal in this case was only hot whilst the RF was flying about. It was cold to the touch the second the power was cut. If it takes no time to cool down I infer there's something more to it. -- "I believe history will be kind to me, since I intend to write it." - Winston Churchill |
On Sat, 09 Aug 2003 00:15:15 GMT, Gary S. Idontwantspam@net wrote:
The example above sounds more like inductive heating. If an ungrounded piece of metal is near an RF energized coil, a current is induced in it which heats it up. Somewhat similar to a microwave oven. I don't see how it can be. The metal in this case was only hot whilst the RF was flying about. It was cold to the touch the second the power was cut. If it takes no time to cool down I infer there's something more to it. -- "I believe history will be kind to me, since I intend to write it." - Winston Churchill |
On Fri, 8 Aug 2003 18:25:06 -0500, "john graesser"
wrote: That wasn't the scariest shock event in my life, I was driving down the highway, and felt the hair raise up on my arms. Then there was a boom and my car radio stopped working. That was the one time that I was in a lightning event. For a moment there I thought you were about to tell us you were abducted by aliens. :-) -- "I believe history will be kind to me, since I intend to write it." - Winston Churchill |
On Fri, 8 Aug 2003 18:25:06 -0500, "john graesser"
wrote: That wasn't the scariest shock event in my life, I was driving down the highway, and felt the hair raise up on my arms. Then there was a boom and my car radio stopped working. That was the one time that I was in a lightning event. For a moment there I thought you were about to tell us you were abducted by aliens. :-) -- "I believe history will be kind to me, since I intend to write it." - Winston Churchill |
No, the GFCI doesn't need the safety ground. Like the device you're
describing, it measures the difference between the "hot" and "neutral" wires, by running the pair together through a transformer. A GFCI is supposed to trip in 1/40 of a second at 5 mA. In our system, like yours, the "hot" and "neutral" wires should always carry equal currents, and the safety ground shouldn't carry any. However, the safety ground is sized the same as the current-carrying conductors so it'll handle a fault current large enough to kick the circuit breaker. Its primary function is to protect against something like the "hot" wire making contact with a metal appliance frame, which should be connected to the safety ground. When it comes to a GFCI, no assumption is made about how much of the imbalance current is returned via the safety ground and how much via the Earth or some other path. Roy Lewallen, W7EL Ian White, G3SEK wrote: Paul Burridge wrote: Ground Fault Circuit Interruptor. How splendid! We call them Residual Current Circuit Breakers in England. That may not be an accurate translation. As I understand it, the GFCI requires a ground connection in order to operate, while the RCB does not. The RCB functions on the difference between the outgoing 'live' current and the return current in the neutral. In the British house wiring system, those two currents should be *exactly* equal, and the difference (the 'residual current') should be zero. Any difference at all means something's wrong - ping - you're disconnected. A typical household RCB will trip on a 60 or 100mA difference in supply current surges up to 60A. That's pretty good common-mode rejection! RCDs can also be cascaded, so an even more sensitive RCD can be used to protect an outdoor mains socket or a workbench. We used to have something like GFCIs over here, but changed to RCDs because RCDs still work if the entire house ground connection has failed. |
No, the GFCI doesn't need the safety ground. Like the device you're
describing, it measures the difference between the "hot" and "neutral" wires, by running the pair together through a transformer. A GFCI is supposed to trip in 1/40 of a second at 5 mA. In our system, like yours, the "hot" and "neutral" wires should always carry equal currents, and the safety ground shouldn't carry any. However, the safety ground is sized the same as the current-carrying conductors so it'll handle a fault current large enough to kick the circuit breaker. Its primary function is to protect against something like the "hot" wire making contact with a metal appliance frame, which should be connected to the safety ground. When it comes to a GFCI, no assumption is made about how much of the imbalance current is returned via the safety ground and how much via the Earth or some other path. Roy Lewallen, W7EL Ian White, G3SEK wrote: Paul Burridge wrote: Ground Fault Circuit Interruptor. How splendid! We call them Residual Current Circuit Breakers in England. That may not be an accurate translation. As I understand it, the GFCI requires a ground connection in order to operate, while the RCB does not. The RCB functions on the difference between the outgoing 'live' current and the return current in the neutral. In the British house wiring system, those two currents should be *exactly* equal, and the difference (the 'residual current') should be zero. Any difference at all means something's wrong - ping - you're disconnected. A typical household RCB will trip on a 60 or 100mA difference in supply current surges up to 60A. That's pretty good common-mode rejection! RCDs can also be cascaded, so an even more sensitive RCD can be used to protect an outdoor mains socket or a workbench. We used to have something like GFCIs over here, but changed to RCDs because RCDs still work if the entire house ground connection has failed. |
A typical household RCB will trip on a 60 or 100mA difference in supply
current surges up to 60A. That's pretty good common-mode rejection! ========== Don't want to be pedantic but the RCDs in domestic switchboards in the UK (at least here in Scotland ) trip at 30 mA . I just had a look at my house's switch board made by SQUARE -D (England) to British Standard BS5486 pt 13 In UK industry I have come across RCDs which trip at 100 mA Frank GM0CSZ / KN6WH |
A typical household RCB will trip on a 60 or 100mA difference in supply
current surges up to 60A. That's pretty good common-mode rejection! ========== Don't want to be pedantic but the RCDs in domestic switchboards in the UK (at least here in Scotland ) trip at 30 mA . I just had a look at my house's switch board made by SQUARE -D (England) to British Standard BS5486 pt 13 In UK industry I have come across RCDs which trip at 100 mA Frank GM0CSZ / KN6WH |
Paul Burridge wrote:
On Sat, 9 Aug 2003 09:01:05 +0100, "Ian White, G3SEK" wrote: A typical household RCB will trip on a 60 or 100mA difference in supply current surges up to 60A. That's pretty good common-mode rejection! It's better than that. 30mA is the standard currently. Sorry, I got mixed-up about that. Our house was wired under the older regulations which allowed the lights to be protected by a separate 100mA RCD, while the power outlets are protected at 30mA. The idea was that tripping a power circuit is less likely to plunge the whole house into darkness. The standard for new household installations is now 30mA all around, although 100mA units are still available for industrial uses. -- 73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB) Editor, 'The VHF/UHF DX Book' http://www.ifwtech.co.uk/g3sek |
Paul Burridge wrote:
On Sat, 9 Aug 2003 09:01:05 +0100, "Ian White, G3SEK" wrote: A typical household RCB will trip on a 60 or 100mA difference in supply current surges up to 60A. That's pretty good common-mode rejection! It's better than that. 30mA is the standard currently. Sorry, I got mixed-up about that. Our house was wired under the older regulations which allowed the lights to be protected by a separate 100mA RCD, while the power outlets are protected at 30mA. The idea was that tripping a power circuit is less likely to plunge the whole house into darkness. The standard for new household installations is now 30mA all around, although 100mA units are still available for industrial uses. -- 73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB) Editor, 'The VHF/UHF DX Book' http://www.ifwtech.co.uk/g3sek |
Roy Lewallen wrote:
No, the GFCI doesn't need the safety ground. Like the device you're describing, it measures the difference between the "hot" and "neutral" wires, by running the pair together through a transformer. A GFCI is supposed to trip in 1/40 of a second at 5 mA. In our system, like yours, the "hot" and "neutral" wires should always carry equal currents, and the safety ground shouldn't carry any. However, the safety ground is sized the same as the current-carrying conductors so it'll handle a fault current large enough to kick the circuit breaker. That is pretty much the same as our RCDs, right down to the large-sized 'protective earth' wire. Its primary function is to protect against something like the "hot" wire making contact with a metal appliance frame, which should be connected to the safety ground. 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"?) 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? 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... When it comes to a GFCI, no assumption is made about how much of the imbalance current is returned via the safety ground and how much via the Earth or some other path. Exactly the same as our RCD, then... just a slightly ambiguous name. -- 73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB) Editor, 'The VHF/UHF DX Book' http://www.ifwtech.co.uk/g3sek |
Roy Lewallen wrote:
No, the GFCI doesn't need the safety ground. Like the device you're describing, it measures the difference between the "hot" and "neutral" wires, by running the pair together through a transformer. A GFCI is supposed to trip in 1/40 of a second at 5 mA. In our system, like yours, the "hot" and "neutral" wires should always carry equal currents, and the safety ground shouldn't carry any. However, the safety ground is sized the same as the current-carrying conductors so it'll handle a fault current large enough to kick the circuit breaker. That is pretty much the same as our RCDs, right down to the large-sized 'protective earth' wire. Its primary function is to protect against something like the "hot" wire making contact with a metal appliance frame, which should be connected to the safety ground. 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"?) 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? 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... When it comes to a GFCI, no assumption is made about how much of the imbalance current is returned via the safety ground and how much via the Earth or some other path. Exactly the same as our RCD, then... just a slightly ambiguous name. -- 73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB) Editor, 'The VHF/UHF DX Book' http://www.ifwtech.co.uk/g3sek |
In article ,
mentioned... Chris1 wrote: In article , "Michael A. Terrell" wrote: I find that very interesting, since every chocolate bar I have ever had was wrapped in aluminum foil. I always thought it was just shiny paper. There's not much Aluminum there, if any. Chris A very thin aluminum foil, with a paper backing. Use an Ohm meter on a piece to see that it is conductive. I used to be able to do that with the nickle plated antistatic bags that parts came in back in 1980. The ohmmeter would measure several hundred ohms. But nowadays all I can measure is an open. I just tried it again, measured open even on the 200M range. -- @@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@ h@e@r@e@@ ###Got a Question about ELECTRONICS? Check HERE First:### http://users.pandora.be/educypedia/e...s/databank.htm My email address is whitelisted. *All* email sent to it goes directly to the trash unless you add NOSPAM in the Subject: line with other stuff. alondra101 at hotmail.com Don't be ripped off by the big book dealers. Go to the URL that will give you a choice and save you money(up to half). http://www.everybookstore.com You'll be glad you did! Just when you thought you had all this figured out, the gov't changed it: http://physics.nist.gov/cuu/Units/binary.html @@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@ u@e@n@t@@ |
In article ,
mentioned... Chris1 wrote: In article , "Michael A. Terrell" wrote: I find that very interesting, since every chocolate bar I have ever had was wrapped in aluminum foil. I always thought it was just shiny paper. There's not much Aluminum there, if any. Chris A very thin aluminum foil, with a paper backing. Use an Ohm meter on a piece to see that it is conductive. I used to be able to do that with the nickle plated antistatic bags that parts came in back in 1980. The ohmmeter would measure several hundred ohms. But nowadays all I can measure is an open. I just tried it again, measured open even on the 200M range. -- @@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@ h@e@r@e@@ ###Got a Question about ELECTRONICS? Check HERE First:### http://users.pandora.be/educypedia/e...s/databank.htm My email address is whitelisted. *All* email sent to it goes directly to the trash unless you add NOSPAM in the Subject: line with other stuff. alondra101 at hotmail.com Don't be ripped off by the big book dealers. Go to the URL that will give you a choice and save you money(up to half). http://www.everybookstore.com You'll be glad you did! Just when you thought you had all this figured out, the gov't changed it: http://physics.nist.gov/cuu/Units/binary.html @@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@ u@e@n@t@@ |
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. Now that you've explained what you meant, I'll mention that I must be on at least my fifth parallel Universe. I told a few tales about my "teleportation experiments" here some time back, all involving from 220VAC @ 60 Hz to a few kV @ 400 Hz. I tend to jump rather than tear muscles because I'm skinny, you see. Mark L. Fergerson |
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. Now that you've explained what you meant, I'll mention that I must be on at least my fifth parallel Universe. I told a few tales about my "teleportation experiments" here some time back, all involving from 220VAC @ 60 Hz to a few kV @ 400 Hz. I tend to jump rather than tear muscles because I'm skinny, you see. Mark L. Fergerson |
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... |
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