peach james Posted January 5, 2019 Share Posted January 5, 2019 Rare in hotel rooms, rare in US Army facilities, and pretty unusual in most of the private homes I’ve been in. People seem to have hob kettles more though. And I have spent a lot of time in the USA. I don't know- there's one sitting right behind me, there's one next door in my mate's house, one up at the fire hall, one at work, more than one at my dad's, at least one in my mum's and at my sisters... It's not a scientific study, but I'd suggest quite a few people have electric kettles. Yes, they are 1.5 kw, but they do an adaquate job of boiling water. A 1.5 kw heater will run a Stuart Turner #9... (1 1/4 * 1 1/2", it was sleaved) James Link to post Share on other sites More sharing options...
Junctionmad Posted January 5, 2019 Share Posted January 5, 2019 (edited) Agreed - which Kevin was kind enough to explain in a considerably politer / less insulting tone than you back in post number 114 Yes but this was explained to you way back and you persisted in posting faulty analysis , that is what bugged me Edited January 5, 2019 by Junctionmad 1 Link to post Share on other sites More sharing options...
Junctionmad Posted January 5, 2019 Share Posted January 5, 2019 (edited) I don't know- there's one sitting right behind me, there's one next door in my mate's house, one up at the fire hall, one at work, more than one at my dad's, at least one in my mum's and at my sisters... It's not a scientific study, but I'd suggest quite a few people have electric kettles. Yes, they are 1.5 kw, but they do an adaquate job of boiling water. A 1.5 kw heater will run a Stuart Turner #9... (1 1/4 * 1 1/2", it was sleaved) James I personally never saw many kettles in the US , when I lived there , ( known as tea kettles ) largely because many people didn’t make tea , pour over was largely commonplace , today I see more capsule machines As for power ratings , most are 1509 to 2000 W , 1500 is adequate for small kettles Edited January 5, 2019 by Junctionmad Link to post Share on other sites More sharing options...
RMweb Premium phil-b259 Posted January 5, 2019 RMweb Premium Share Posted January 5, 2019 Crosland The flaw with applying Ohm’s Law to animals, us included, is that we aren’t nice, neat linear resistors. We are grubby, sweaty, bags of stuff saturated in salty water, so are prone to surface tracking, sudden change of bulk resistance at threshold voltages etc etc. Quite so - which was why I talked specifically about the current being passed across the heart muscles in post 127. Obviously if you stand there holding a 1.5V AA battery between your thumbs you do not suffer any harm (though there most definitely must be electricity flowing through you) and I hypothesise the electricity is practically guaranteed to simply flow through the upper layers of skin and go nowhere near your heart. Increase the battery to a typical car battery and the electricity will probably permeate deeper and has more chances of interfering with your internals. Do the same to a mains supply and obviously the chances of some of that electricity making its way across your heart muscles are high - however it is unlikely to be the full supply voltage for the reason Kevin stated. I would also imagine that the electrical charge a high voltage (but low current) shock from a cattle fence also travels via the outer layers of your body while a low voltage but high current discharge will penetrate deeper - thus confirming my thoughts that current is far more critical when it comes to electric shocks than voltages. This is why I was dismissive about the actual voltage necessary to disrupt the heart. Given the only reason we are able to breathe, move our hands and discuss this topic is because our bodies are continually transmitting low voltage electricity around our brains and onto our muscles (a regular heartbeat only happens because of electric impulses sent from the brain after all), and although I am no biologist, the voltages / currents involved to make these things happen are probably far smaller than the voltages / currents in a typical AA battery. Consequently while various regulatory bodies may well have determined that 50V AC RMS / 120V DC counts as a 'low electrocution risk' that does not mean it is safe to apply directly to the heart. What is more likely is that after taking into account variables like the average resistance of skin ,flesh and bone in a human body by the time the electrical charge has got to the heart itself, the current and voltage actually drooped across the heart itself from said 'low electrocution risk' supplies is unlikely to disrupt the natural heart rythams. P.S. This post is made in a light hearted QI style with the expectation that if there are errors, folk will take the trouble to enlighten me in polite manor. The 'experts' on this thread who seem to like lording it over others who lack knowledge or make mistakes need not reply... Link to post Share on other sites More sharing options...
RMweb Premium phil-b259 Posted January 5, 2019 RMweb Premium Share Posted January 5, 2019 (edited) Yes but this was explained to you way back and you persisted in posting faulty analysis , that is what bugged me Not everyone explains or understand things in the same way. I have been on a fair few training courses in my time where the instructor might of been a nice person, and technically very good at the subject - but they simply lacked the ability to teach effectively. Its why teachers in schools can be so variable too - there is a knack to getting the best out of a class which not everyone can master. A significant part of this is an ability to recognise when someone is struggling to 'get' what the issues are - which is even harder on a internet forum particularly if they have autistic tendencies and the visual feedback loops you get with face to face conversation are absent. The way Kevin engaged and slowly took me through my errors using the examples I had given was how I expected it to be done - not just selectively quoting lines and going 'your wrong because of X' Edited January 5, 2019 by phil-b259 1 Link to post Share on other sites More sharing options...
AndyID Posted January 5, 2019 Share Posted January 5, 2019 I would also imagine that the electrical charge a high voltage (but low current) shock from a cattle fence also travels via the outer layers of your body while a low voltage but high current discharge will penetrate deeper - thus confirming my thoughts that current is far more critical when it comes to electric shocks than voltages. :banghead: You can imagine all you like but the only way to get a high current to penetrate a human body is from a high voltage, low impedance (resistance) source. It's dictated by Ohm's law. Link to post Share on other sites More sharing options...
RMweb Gold Colin_McLeod Posted January 5, 2019 RMweb Gold Share Posted January 5, 2019 Recommended reading for some delusional posters on this thread. https://www.amazon.co.uk/Electronics-All-One-Reference-Dummies/dp/1118589734/ref=mp_s_a_1_1?ie=UTF8&qid=1546678993&sr=8-1&pi=AC_SX236_SY340_FMwebp_QL65&keywords=electricity+for+dummies&dpPl=1&dpID=614RXulqqqL&ref=plSrch Link to post Share on other sites More sharing options...
RMweb Premium Mallard60022 Posted January 5, 2019 RMweb Premium Share Posted January 5, 2019 I have my Circuit Breakers and appropriate Fire Extinguishers to hand when at home and always turn off/ unplug stuff when we go away & whether that is necessary or not,I do it same as I unplug the TV aerial in thundery weather. Don't care if that is pointless, it makes me feel safer. I also have all electrical work, even quite simple stuff, done by a trusted Electrician. However, probably the most dangerous wiring in the house is that done under my layout by me, hence the CB and FEs and I always turn off power when not at the layout. By the way, it is unwise to google hotplug unless you enjoy viewing exotic activity involving persons. Ar$£ Link to post Share on other sites More sharing options...
Pacific231G Posted January 5, 2019 Share Posted January 5, 2019 (edited) :banghead: You can imagine all you like but the only way to get a high current to penetrate a human body is from a high voltage, low impedance (resistance) source. It's dictated by Ohm's law. Quite so - which was why I talked specifically about the current being passed across the heart muscles in post 127. Obviously if you stand there holding a 1.5V AA battery between your thumbs you do not suffer any harm (though there most definitely must be electricity flowing through you) and I hypothesise the electricity is practically guaranteed to simply flow through the upper layers of skin and go nowhere near your heart. Increase the battery to a typical car battery and the electricity will probably permeate deeper and has more chances of interfering with your internals. Do the same to a mains supply and obviously the chances of some of that electricity making its way across your heart muscles are high - however it is unlikely to be the full supply voltage for the reason Kevin stated. I would also imagine that the electrical charge a high voltage (but low current) shock from a cattle fence also travels via the outer layers of your body while a low voltage but high current discharge will penetrate deeper - thus confirming my thoughts that current is far more critical when it comes to electric shocks than voltages. This is why I was dismissive about the actual voltage necessary to disrupt the heart. Given the only reason we are able to breathe, move our hands and discuss this topic is because our bodies are continually transmitting low voltage electricity around our brains and onto our muscles (a regular heartbeat only happens because of electric impulses sent from the brain after all), and although I am no biologist, the voltages / currents involved to make these things happen are probably far smaller than the voltages / currents in a typical AA battery. Consequently while various regulatory bodies may well have determined that 50V AC RMS / 120V DC counts as a 'low electrocution risk' that does not mean it is safe to apply directly to the heart. What is more likely is that after taking into account variables like the average resistance of skin ,flesh and bone in a human body by the time the electrical charge has got to the heart itself, the current and voltage actually drooped across the heart itself from said 'low electrocution risk' supplies is unlikely to disrupt the natural heart rythams. P.S. This post is made in a light hearted QI style with the expectation that if there are errors, folk will take the trouble to enlighten me in polite manor. The 'experts' on this thread who seem to like lording it over others who lack knowledge or make mistakes need not reply... I'm no expert, it's a long time since I studied electrical engineering and did a wiring course but you might find it helpful to think of electicity as somewhat analogous to water flow. In that analogy voltage is analogous to pressure, current to the total amount of water flowing and any constriction of the pipe analogous to resistance The higher the pressure (voltage) in a particular pipe the more water will flow through it over a particular time (current) but the smaller the pipe (higher resistance) the less water will flow for a particular pressure. Try to increase the pressure in a small pipe to achieve a larger flow of water and eventually the pipe will burst (an electical conductor will burn out) but with no pressure (zero volts) no water will flow however large the pipe. A fast flowing river running through rapids down a steep hillside can be much smaller than the same river further downstream that is larger and slower flowing carrying the same amount of water per hour (you can observe that at any weir). This also means that a hydroelectric plant can generate a lot of power if the reservoir is high above it so the pressure is also high even though the pipes feeding it may be relatively small. Howwever a water wheel further downstream, even if it uses the same amount of water but with a drop of only a few feet will generate far less.power. You can't really take this analogy much further as electricity and water are very different (for example, water can travel at different speeds in pipes) and very very different with alternating current but some people find it helpful. Cattle fences deliver high voltages of up to eight thousand volts but from capacitors with a limited capacity so in very short pulses of typically 1/300th of a second. If you do touch one (not advisable) you'll get an unpleasant shock from the iniitial voltage and current flow but that and the corresponding current will drop to zero so fast that it probably won't do you any harm.(It's the same principle as the Capacitor Discharge Units we use to provide enough instantaneous power to shift a set of points but in a short pulse that won't burn the point motor out) Just walking around can charge you up to a voltage of tens of thousands of volts which you'll certainly feel when you touch a metal object but the total energy you;re carrying is so small that it won't hurt you (It might though be enough to burn out a chip if you discharge yourself through that) A static charge may also be carry enouigh energy to ignite an inflammable gas or liquid which is why aircraft, which can pick up a considerable static charge while flying, need to be grounded - often with an earthing cable connected to the pump- before being refuellled. An electric shock across the heart is likely to be deadlier than one that isn't which is why some electricians put one hand in their pocket (and wear insulating footwear) when dealing with potentially live circuits. That doesn't make working on live circuits a sensible idea. The mnemonic that for some reason I still remember fifty years after studying electrical engineering was "SIDE" Switch Off, Isolate, Dump (as in capacitors) Earth before working on any electrical plant. And just because something like a DVD player hasn't been used or even plugged in for some time doesn't mean that there aren't lethal charges still lurking in the capacitors (a freind who fixes such things for a living warned me about that) Edited January 5, 2019 by Pacific231G Link to post Share on other sites More sharing options...
RMweb Premium phil-b259 Posted January 5, 2019 RMweb Premium Share Posted January 5, 2019 (edited) :banghead: You can imagine all you like...... Totally unnecessary start Mr 'Know it all'. Try re-reading post 180 ........the only way to get a high current to penetrate a human body is from a high voltage, low impedance (resistance) source...... Useful and educational information ..... It's dictated by Ohm's law. Unhelpful quoting without qualification. Do you mean to say that the current which flows through / around a human body will be dependent on the resistance of the path it takes round / through said body? If so then I think Kevin already made that point in post 136 or are you trying to say that electric shocks are only possible with low impedance supplies (total nonsense as I have received electric shocks from high impedance transformers before) Edited January 5, 2019 by phil-b259 Link to post Share on other sites More sharing options...
raymw Posted January 5, 2019 Share Posted January 5, 2019 Not directed at any posting in particular, but my overall impression of this thread, for anyone reading it, or coming across it, my advice is ignore it completely. Unless you fully understand electrickery, you will be unable to decide correctly as to who speaketh the truth, and if you try and base anything that you do as a consequence of reading anything here, then a minor or major disaster could happen. In this particular instance, a little knowledge is a dangerous thing. 1 Link to post Share on other sites More sharing options...
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