Electrical Safe Tea
Gentlemen,
I've just come up with a very simple idea to massively improve safe- working in high voltage cabinets where testing has to be done live. In fact it's so simple there must surely be some flaw in it that I've overlooked (or there's already some obscure product that covers it). Tell me what you think. Firstly, when I say "high voltage cabinets" I'm not necessarily referring to mains consumer units and whatnot (although this idea is equally valid for those) I find it easier to visualise (for the sake of getting the concept across) working on an old analogue TV for example, where you have all sorts of voltages present, including some highly lethal ones in excess of 10kV. The main thing we need to avoid is suffering a shock where the current passes through or nearby the heart. This is *most* shocks when you're fiddling about inside such environments with both hands. The standard advice has been "well, keep one hand inside your back pocket, then" but this means of course you only have one hand to prod around with which is constricting. I'm proposing to short-out both wrists using a metallic bracelet on each, tied to one another via a couple of feet of light, flexible cable. So for example if you're prodding around with your right hand whilst somehow touching the chassis with your left and you touch something live, the current will only flow through your hands and wrists rather than up your arms and across your chest. And that's all there is to it. Now, where have I gone wrong? (I must have done somewhere!) -- This message may be freely reproduced without limit or charge only via the Usenet protocol. Reproduction in whole or part through other protocols, whether for profit or not, is conditional upon a charge of GBP10.00 per reproduction. Publication in this manner via non-Usenet protocols constitutes acceptance of this condition. |
Electrical Safe Tea
On 01/10/2017 12:27, Cursitor Doom wrote:
Gentlemen, I've just come up with a very simple idea to massively improve safe- working in high voltage cabinets where testing has to be done live. In fact it's so simple there must surely be some flaw in it that I've overlooked (or there's already some obscure product that covers it). Tell me what you think. Firstly, when I say "high voltage cabinets" I'm not necessarily referring to mains consumer units and whatnot (although this idea is equally valid for those) I find it easier to visualise (for the sake of getting the concept across) working on an old analogue TV for example, where you have all sorts of voltages present, including some highly lethal ones in excess of 10kV. The main thing we need to avoid is suffering a shock where the current passes through or nearby the heart. This is *most* shocks when you're fiddling about inside such environments with both hands. The standard advice has been "well, keep one hand inside your back pocket, then" but this means of course you only have one hand to prod around with which is constricting. I'm proposing to short-out both wrists using a metallic bracelet on each, tied to one another via a couple of feet of light, flexible cable. So for example if you're prodding around with your right hand whilst somehow touching the chassis with your left and you touch something live, the current will only flow through your hands and wrists rather than up your arms and across your chest. And that's all there is to it. Now, where have I gone wrong? (I must have done somewhere!) You are assuming a conductive skin, maybe OK for Tesla coil type high frequency AC voltages. The current path will be through blood and other bodily fluids. |
Electrical Safe Tea
On 01/10/2017 12:27, Cursitor Doom wrote:
Gentlemen, I've just come up with a very simple idea to massively improve safe- working in high voltage cabinets where testing has to be done live. In fact it's so simple there must surely be some flaw in it that I've overlooked (or there's already some obscure product that covers it). Tell me what you think. Firstly, when I say "high voltage cabinets" I'm not necessarily referring to mains consumer units and whatnot (although this idea is equally valid for those) I find it easier to visualise (for the sake of getting the concept across) working on an old analogue TV for example, where you have all sorts of voltages present, including some highly lethal ones in excess of 10kV. The main thing we need to avoid is suffering a shock where the current passes through or nearby the heart. This is *most* shocks when you're fiddling about inside such environments with both hands. The standard advice has been "well, keep one hand inside your back pocket, then" but this means of course you only have one hand to prod around with which is constricting. I'm proposing to short-out both wrists using a metallic bracelet on each, tied to one another via a couple of feet of light, flexible cable. So for example if you're prodding around with your right hand whilst somehow touching the chassis with your left and you touch something live, the current will only flow through your hands and wrists rather than up your arms and across your chest. And that's all there is to it. Now, where have I gone wrong? (I must have done somewhere!) Perhaps you can measure, with a low, safe voltage, current entering the hands and that passing from one hand to the other with your contraption. Please do report back with your findings, however I suspect once current enters the body little will come back out through skin and be bypassed by your wigget. BICBW What you need is what this guy wears! I doubt it take much current though: https://www.youtube.com/watch?v=9tzga6qAaBA |
Electrical Safe Tea
On Sun, 1 Oct 2017 11:27:51 -0000 (UTC), Cursitor Doom
coalesced the vapors of human experience into a viable and meaningful comprehension... Gentlemen, I've just come up with a very simple idea to massively improve safe- working in high voltage cabinets where testing has to be done live. In fact it's so simple there must surely be some flaw in it that I've overlooked (or there's already some obscure product that covers it). Tell me what you think. Firstly, when I say "high voltage cabinets" I'm not necessarily referring to mains consumer units and whatnot (although this idea is equally valid for those) I find it easier to visualise (for the sake of getting the concept across) working on an old analogue TV for example, where you have all sorts of voltages present, including some highly lethal ones in excess of 10kV. The main thing we need to avoid is suffering a shock where the current passes through or nearby the heart. This is *most* shocks when you're fiddling about inside such environments with both hands. The standard advice has been "well, keep one hand inside your back pocket, then" but this means of course you only have one hand to prod around with which is constricting. I'm proposing to short-out both wrists using a metallic bracelet on each, tied to one another via a couple of feet of light, flexible cable. So for example if you're prodding around with your right hand whilst somehow touching the chassis with your left and you touch something live, the current will only flow through your hands and wrists rather than up your arms and across your chest. And that's all there is to it. Now, where have I gone wrong? (I must have done somewhere!) Ah, "Safe Tea" was a play on words was it? I visualised having to hold a mug of tea in one hand while I prodded about with the other. I remember being taught that eating or drinking whilst sustaining a shock put you in danger of choking to death, not advice I have heeded to any great extent. -- Graham. %Profound_observation% |
Electrical Safe Tea
On Sun, 01 Oct 2017 14:21:50 +0100, Fredxxx wrote:
Perhaps you can measure, with a low, safe voltage, current entering the hands and that passing from one hand to the other with your contraption. "Contraption" indeed! Hardly a contraption by any definition. Please do report back with your findings, however I suspect once current enters the body little will come back out through skin and be bypassed by your wigget. Must admit I hadn't considered skin resistance as you and newsy mentioned. HOWEVER I do have some conductive electrode lube I've not had cause to use for a different project I was working on. Be interesting to try your test with and without the lube; it might just make that critical difference. -- This message may be freely reproduced without limit or charge only via the Usenet protocol. Reproduction in whole or part through other protocols, whether for profit or not, is conditional upon a charge of GBP10.00 per reproduction. Publication in this manner via non-Usenet protocols constitutes acceptance of this condition. |
Electrical Safe Tea
What you need is what this guy wears! I doubt it take much current though: https://www.youtube.com/watch?v=9tzga6qAaBA This is the powerline work I like: https://www.youtube.com/watch?v=Mfz1YrpMbBg -- Davey. |
Electrical Safe Tea
On Sun, 01 Oct 2017 14:21:50 +0100, Fredxxx wrote:
What you need is what this guy wears! I doubt it take much current though: https://www.youtube.com/watch?v=9tzga6qAaBA Presumably those two cables are at the same potential and *in* phase WRT each other or that suit is going to burn up in a heartbeat! -- This message may be freely reproduced without limit or charge only via the Usenet protocol. Reproduction in whole or part through other protocols, whether for profit or not, is conditional upon a charge of GBP10.00 per reproduction. Publication in this manner via non-Usenet protocols constitutes acceptance of this condition. |
Electrical Safe Tea
On 01/10/17 12:27, Cursitor Doom wrote:
Gentlemen, I've just come up with a very simple idea to massively improve safe- working in high voltage cabinets where testing has to be done live. In fact it's so simple there must surely be some flaw in it that I've overlooked (or there's already some obscure product that covers it). Tell me what you think. Firstly, when I say "high voltage cabinets" I'm not necessarily referring to mains consumer units and whatnot (although this idea is equally valid for those) I find it easier to visualise (for the sake of getting the concept across) working on an old analogue TV for example, where you have all sorts of voltages present, including some highly lethal ones in excess of 10kV. The main thing we need to avoid is suffering a shock where the current passes through or nearby the heart. This is *most* shocks when you're fiddling about inside such environments with both hands. The standard advice has been "well, keep one hand inside your back pocket, then" but this means of course you only have one hand to prod around with which is constricting. I'm proposing to short-out both wrists using a metallic bracelet on each, tied to one another via a couple of feet of light, flexible cable. So for example if you're prodding around with your right hand whilst somehow touching the chassis with your left and you touch something live, the current will only flow through your hands and wrists rather than up your arms and across your chest. And that's all there is to it. Now, where have I gone wrong? (I must have done somewhere!) You really need a couple of these joined together (and earthed?). https://www.scobiesdirect.com/Produc...in+Mail+Gloves -- Jeff |
Electrical Safe Tea
On Sun, 01 Oct 2017 15:41:07 +0100, Jeff Layman wrote:
You really need a couple of these joined together (and earthed?). https://www.scobiesdirect.com/Produc...in+Mail+Gloves I see where you're coming from here, but gloves like that rob you of the sensitivity you need for much investigative troubleshooting. And yes, they will need to be earthed *if* you're not using an isolation transformer to power up the DUT. -- This message may be freely reproduced without limit or charge only via the Usenet protocol. Reproduction in whole or part through other protocols, whether for profit or not, is conditional upon a charge of GBP10.00 per reproduction. Publication in this manner via non-Usenet protocols constitutes acceptance of this condition. |
Electrical Safe Tea
On 01/10/17 16:37, Cursitor Doom wrote:
On Sun, 01 Oct 2017 15:41:07 +0100, Jeff Layman wrote: You really need a couple of these joined together (and earthed?). https://www.scobiesdirect.com/Produc...in+Mail+Gloves I see where you're coming from here, but gloves like that rob you of the sensitivity you need for much investigative troubleshooting. And yes, they will need to be earthed *if* you're not using an isolation transformer to power up the DUT. It was a suggestion half made in jest. But one thing they would stop - which wrist bracelets would not - are arc burns down unprotected skin. These are absolute buggers to heal, as the underlying tissue is superheated and killed. Many people only consider the shock problem, but the burn can be a serious issue: https://en.wikipedia.org/wiki/Electrical_burn -- Jeff |
Electrical Safe Tea
On Sun, 01 Oct 2017 16:47:40 +0100, Jeff Layman wrote:
It was a suggestion half made in jest. But one thing they would stop - which wrist bracelets would not - are arc burns down unprotected skin. These are absolute buggers to heal, as the underlying tissue is superheated and killed. I did refine the concept following a bit of feedback from early in the thread. Electrode lube will improve conductivity and reduce any skin burning. And burning takes time, even if only a little time. So a worthwhile addition would be something to instantly cut the power in the event of the detection of a fault current. Something easily re-settable perhaps (if you're planning on making a habit of getting electrocuted). Many people only consider the shock problem, but the burn can be a serious issue: https://en.wikipedia.org/wiki/Electrical_burn Yeah, but better burned than killed. -- This message may be freely reproduced without limit or charge only via the Usenet protocol. Reproduction in whole or part through other protocols, whether for profit or not, is conditional upon a charge of GBP10.00 per reproduction. Publication in this manner via non-Usenet protocols constitutes acceptance of this condition. |
Electrical Safe Tea
On Sunday, 1 October 2017 12:27:53 UTC+1, Cursitor Doom wrote:
,,, I'm proposing to short-out both wrists using a metallic bracelet on each, tied to one another via a couple of feet of light, flexible cable. I haven't seen any products in Ann Summers marked as VDE tested :-) Owain |
Electrical Safe Tea
On Sun, 1 Oct 2017 11:27:51 -0000 (UTC), Cursitor Doom
wrote: Gentlemen, I've just come up with a very simple idea to massively improve safe- working in high voltage cabinets where testing has to be done live.The main thing we need to avoid is suffering a shock where the current passes through or nearby the heart. This is *most* shocks when you're fiddling about inside such environments with both hands. I'm proposing to short-out both wrists using a metallic bracelet on each, tied to one another via a couple of feet of light, flexible cable. So for example if you're prodding around with your right hand whilst somehow touching the chassis with your left and you touch something live, the current will only flow through your hands and wrists rather than up your arms and across your chest. And that's all there is to it. Now, where have I gone wrong? (I must have done somewhere!) I would have though that for added safety you would need to ground your connecting wire so it removes the resistance of one wrist and set of fingers , a wire dragging around is almost bound to snag on something sometime and pull a hand onto something live that if it were free would have stayed clear so it doesn't actually sound that practical. better not to allow any current through in the first place and wear insulating gloves. G.Harman |
Electrical Safe Tea
On 01/10/2017 14:34, Cursitor Doom wrote:
On Sun, 01 Oct 2017 14:21:50 +0100, Fredxxx wrote: Perhaps you can measure, with a low, safe voltage, current entering the hands and that passing from one hand to the other with your contraption. "Contraption" indeed! Hardly a contraption by any definition. Nerve hit? Please do report back with your findings, however I suspect once current enters the body little will come back out through skin and be bypassed by your wigget. Must admit I hadn't considered skin resistance as you and newsy mentioned. HOWEVER I do have some conductive electrode lube I've not had cause to use for a different project I was working on. Be interesting to try your test with and without the lube; it might just make that critical difference. Except getting any conductive lube on one's hand mights create a greater risk of conduction into your arms. Perhaps spikes penetrating the skin on wrists? :-) What might be an idea is to measure voltage across shoulders and pass an equal and opposite current through the wrists? You just have to remember to take electrodes off in the right order! |
Electrical Safe Tea
On 01/10/2017 14:43, Cursitor Doom wrote:
On Sun, 01 Oct 2017 14:21:50 +0100, Fredxxx wrote: What you need is what this guy wears! I doubt it take much current though: https://www.youtube.com/watch?v=9tzga6qAaBA Presumably those two cables are at the same potential and *in* phase WRT each other or that suit is going to burn up in a heartbeat! He did say it had fire-resistant fibres, so I guess even if you didn't survive the suit would. I understand those cables carry an awful lot of current. Bundles are commonly used for improved cooling and are easier to handle. |
Electrical Safe Tea
On 01/10/2017 17:04, Cursitor Doom wrote:
On Sun, 01 Oct 2017 16:47:40 +0100, Jeff Layman wrote: It was a suggestion half made in jest. But one thing they would stop - which wrist bracelets would not - are arc burns down unprotected skin. These are absolute buggers to heal, as the underlying tissue is superheated and killed. I did refine the concept following a bit of feedback from early in the thread. Electrode lube will improve conductivity and reduce any skin burning. And burning takes time, even if only a little time. So a worthwhile addition would be something to instantly cut the power in the event of the detection of a fault current. Something easily re-settable perhaps (if you're planning on making a habit of getting electrocuted). Many people only consider the shock problem, but the burn can be a serious issue: https://en.wikipedia.org/wiki/Electrical_burn Yeah, but better burned than killed. Not when you eventually die from your internal burns. Some survive the initial shock/burn and then go onto die later. |
Electrical Safe Tea
wrote:
On Sun, 1 Oct 2017 11:27:51 -0000 (UTC), Cursitor Doom wrote: Gentlemen, I've just come up with a very simple idea to massively improve safe- working in high voltage cabinets where testing has to be done live.The main thing we need to avoid is suffering a shock where the current passes through or nearby the heart. This is *most* shocks when you're fiddling about inside such environments with both hands. I'm proposing to short-out both wrists using a metallic bracelet on each, tied to one another via a couple of feet of light, flexible cable. So for example if you're prodding around with your right hand whilst somehow touching the chassis with your left and you touch something live, the current will only flow through your hands and wrists rather than up your arms and across your chest. And that's all there is to it. Now, where have I gone wrong? (I must have done somewhere!) I would have though that for added safety you would need to ground your connecting wire so it removes the resistance of one wrist and set of fingers , a wire dragging around is almost bound to snag on something sometime and pull a hand onto something live that if it were free would have stayed clear so it doesn't actually sound that practical. better not to allow any current through in the first place and wear insulating gloves. G.Harman I would think that the very last thing you would want to be putting in a high voltage cabinet would be an earthed metal object. You want personal electrical insulation, flash protection and burn protection. But, above all, a very clear idea what you want to touch and what you don't want to touch. And if you are measuring anything as opposed to just turning it on or off then test prods on long insulated holders. One at a time fixed in place. And turning things on and off is probably best done with a long insulated thing. Main rule I would follow is don't go near them unless you have to and have a very clear idea what you are going to do and which bit is which. It it gets to the stage of trying to divert a high voltage from one hand to the other via an alternative path then you have already lost; and you certainly don't want it to be a low resistance path. -- Roger Hayter |
Electrical Safe Tea
On Sun, 01 Oct 2017 18:55:35 +0100, Fredxxx wrote:
Except getting any conductive lube on one's hand mights create a greater risk of conduction into your arms. Yes, you would need to ensure the goo remains on the electrodes only. What might be an idea is to measure voltage across shoulders and pass an equal and opposite current through the wrists? You just have to remember to take electrodes off in the right order! Not quite sure what you're suggesting here, but if it's what I think, it won't help because in the actual application I have in mind (working on live switching power supplies) there are all sorts of voltages up to about 800V present, all capable of supplying enough mills to kill. I think my idea merits further investigation, so I'll do the testing you suggested in an earlier post when time permits. -- This message may be freely reproduced without limit or charge only via the Usenet protocol. Reproduction in whole or part through other protocols, whether for profit or not, is conditional upon a charge of GBP10.00 per reproduction. Publication in this manner via non-Usenet protocols constitutes acceptance of this condition. |
Electrical Safe Tea
On Sun, 01 Oct 2017 19:08:22 +0100, Fredxxx wrote:
Not when you eventually die from your internal burns. Some survive the initial shock/burn and then go onto die later. I think that scenario typically occurs with extremely high voltage power lines or prolonged 'low' voltage shocks (such as when you can't let go of mains live wire due to muscle paralysis). -- This message may be freely reproduced without limit or charge only via the Usenet protocol. Reproduction in whole or part through other protocols, whether for profit or not, is conditional upon a charge of GBP10.00 per reproduction. Publication in this manner via non-Usenet protocols constitutes acceptance of this condition. |
Electrical Safe Tea
On Sunday, 1 October 2017 14:29:55 UTC+1, Graham. wrote:
On Sun, 1 Oct 2017 11:27:51 -0000 (UTC), Cursitor Doom coalesced the vapors of human experience into a viable and meaningful comprehension... Gentlemen, I've just come up with a very simple idea to massively improve safe- working in high voltage cabinets where testing has to be done live. In fact it's so simple there must surely be some flaw in it that I've overlooked (or there's already some obscure product that covers it). Tell me what you think. Firstly, when I say "high voltage cabinets" I'm not necessarily referring to mains consumer units and whatnot (although this idea is equally valid for those) I find it easier to visualise (for the sake of getting the concept across) working on an old analogue TV for example, where you have all sorts of voltages present, including some highly lethal ones in excess of 10kV. The main thing we need to avoid is suffering a shock where the current passes through or nearby the heart. This is *most* shocks when you're fiddling about inside such environments with both hands. The standard advice has been "well, keep one hand inside your back pocket, then" but this means of course you only have one hand to prod around with which is constricting. I'm proposing to short-out both wrists using a metallic bracelet on each, tied to one another via a couple of feet of light, flexible cable. So for example if you're prodding around with your right hand whilst somehow touching the chassis with your left and you touch something live, the current will only flow through your hands and wrists rather than up your arms and across your chest. And that's all there is to it. Now, where have I gone wrong? (I must have done somewhere!) Ah, "Safe Tea" was a play on words was it? I visualised having to hold a mug of tea in one hand while I prodded about with the other. I thought of an administrator working hard drinking tea and talk ******** about something they know nothing about and hence getting put in charge of it a bit like being in charge of glading on buildings. I can't help but think that linking your wrists together with metak is more like some sort of remote handcuff fetish and more likely to cause accidents by gettign tangled in the cable. |
Electrical Safe Tea
On Mon, 02 Oct 2017 08:36:38 +0100, Brian Gaff wrote:
Hmm, well, it might restrict the movement a bit I suppose, but I'm sure I've seen something like it before. You were maybe thinking of one of these, which performs a somewhat different function: http://tinyurl.com/yclwlnw2 -- This message may be freely reproduced without limit or charge only via the Usenet protocol. Reproduction in whole or part through other protocols, whether for profit or not, is conditional upon a charge of GBP10.00 per reproduction. Publication in this manner via non-Usenet protocols constitutes acceptance of this condition. |
Electrical Safe Tea
On Monday, 2 October 2017 11:41:49 UTC+1, Cursitor Doom wrote:
On Mon, 02 Oct 2017 08:36:38 +0100, Brian Gaff wrote: Hmm, well, it might restrict the movement a bit I suppose, but I'm sure I've seen something like it before. You were maybe thinking of one of these, which performs a somewhat different function: http://tinyurl.com/yclwlnw2 or perhaps this. http://www.temptationsdirect.co.uk/x...ngs-Cable.html |
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