Newbie: tips on how to start?
in [Basics]
|
Prev: The ideas of time?
Next: Cheap Wholesale Bape Shoes
From: Sjouke Burry on 14 Jul 2010 20:36 Cydrome Leader wrote: > Baron <baron.nospam(a)linuxmaniac.nospam.net> wrote: >> Cydrome Leader Inscribed thus: >> >>> Sjouke Burry <burrynulnulfour(a)ppllaanneett.nnll> wrote: >>>> Cydrome Leader wrote: >>>>> JW <none(a)dev.null> wrote: >>>>>> On Mon, 12 Jul 2010 21:06:30 +0000 (UTC) Cydrome Leader >>>>>> <presence(a)MUNGEpanix.com> wrote in Message id: >>>>>> <i1g04m$aig$2(a)reader1.panix.com>: >>>>>> >>>>>>> you can grab a cheap am radio, remove the cover and even just poke >>>>>>> around at the parts while it's on. >>>>>> Battery powered of course, if poking with your fingers! >>>>> haha, yes. >>>>> >>>>> So what does mains shock feel like in places with 240? >>>> It makes you see stars, and makes your muscles contract violently. >>>> And there might be a small burn mark. >>>> Having good quality plastic soles under your shoes makes single >>>> contact oke. Dont use leather soles. >>>> My limit fo far is 2X500 volt from a falling radio I tried to >>>> catch..... We both survived. >>>> Automatic reflexes are so dangerous when you work with electricity. >>> Interesting. >>> >>> Here in US with 120, the danger is almost always from what you end up >>> hitting or falling off (like a ladder) /into than from the shock >>> itself. >>> >>> I've never been burned from 120 or seen stars or anything like that. >>> I've touched high voltage DC equipment where it doesn't even matter if >>> only one hand is in the pocket or or anything like that. At 8kV you're >>> getting a one handed shock unless you have special boots on. >>> >>> The last actual line voltage electrocution story from around here was >>> from somebody running an electric drill outdoors on a hot day. They >>> sweated into the drill, couldn't let go and died. >> Possible, but I suspect an urban legend. > > If the chicago suntimes or tribune had a functional search feature, you > could locate the story, but that's a different story. > >>> How often do people drop dead from actual electrocutions in places >>> that use 240, just doing plain tasks like you might at home or >>> outside? >> People do die from electrocution on 240 volt AC mains. More often than >> not the reflex action causes you to pull away. I agree with your >> comment that "the danger is almost always from what you end up hitting >> or falling off (like a ladder) /into than from the shock itself." >> DC is far more likely to kill you, simply because the muscle contracts >> and makes it impossible to let go. > > Is it 240 from either side of the line to ground, or how does that work? I > asked all about this when I was in Ireland, but forgot the answer. > No,1 phase and 1 return. The return is actually the centre tap of the 3 phase system(3 X 240 V), and equivalent to ground.
From: Cydrome Leader on 15 Jul 2010 00:01 Sjouke Burry <burrynulnulfour(a)ppllaanneett.nnll> wrote: > Cydrome Leader wrote: >> Baron <baron.nospam(a)linuxmaniac.nospam.net> wrote: >>> Cydrome Leader Inscribed thus: >>> >>>> Sjouke Burry <burrynulnulfour(a)ppllaanneett.nnll> wrote: >>>>> Cydrome Leader wrote: >>>>>> JW <none(a)dev.null> wrote: >>>>>>> On Mon, 12 Jul 2010 21:06:30 +0000 (UTC) Cydrome Leader >>>>>>> <presence(a)MUNGEpanix.com> wrote in Message id: >>>>>>> <i1g04m$aig$2(a)reader1.panix.com>: >>>>>>> >>>>>>>> you can grab a cheap am radio, remove the cover and even just poke >>>>>>>> around at the parts while it's on. >>>>>>> Battery powered of course, if poking with your fingers! >>>>>> haha, yes. >>>>>> >>>>>> So what does mains shock feel like in places with 240? >>>>> It makes you see stars, and makes your muscles contract violently. >>>>> And there might be a small burn mark. >>>>> Having good quality plastic soles under your shoes makes single >>>>> contact oke. Dont use leather soles. >>>>> My limit fo far is 2X500 volt from a falling radio I tried to >>>>> catch..... We both survived. >>>>> Automatic reflexes are so dangerous when you work with electricity. >>>> Interesting. >>>> >>>> Here in US with 120, the danger is almost always from what you end up >>>> hitting or falling off (like a ladder) /into than from the shock >>>> itself. >>>> >>>> I've never been burned from 120 or seen stars or anything like that. >>>> I've touched high voltage DC equipment where it doesn't even matter if >>>> only one hand is in the pocket or or anything like that. At 8kV you're >>>> getting a one handed shock unless you have special boots on. >>>> >>>> The last actual line voltage electrocution story from around here was >>>> from somebody running an electric drill outdoors on a hot day. They >>>> sweated into the drill, couldn't let go and died. >>> Possible, but I suspect an urban legend. >> >> If the chicago suntimes or tribune had a functional search feature, you >> could locate the story, but that's a different story. >> >>>> How often do people drop dead from actual electrocutions in places >>>> that use 240, just doing plain tasks like you might at home or >>>> outside? >>> People do die from electrocution on 240 volt AC mains. More often than >>> not the reflex action causes you to pull away. I agree with your >>> comment that "the danger is almost always from what you end up hitting >>> or falling off (like a ladder) /into than from the shock itself." >>> DC is far more likely to kill you, simply because the muscle contracts >>> and makes it impossible to let go. >> >> Is it 240 from either side of the line to ground, or how does that work? I >> asked all about this when I was in Ireland, but forgot the answer. >> > No,1 phase and 1 return. > The return is actually the centre tap of the 3 phase system(3 X 240 V), > and equivalent to ground. So it's usually some sort of Wye connection where one side of the power would in theory br safe to just touch if you were standing in a puddle? What's confusing in the USA is the mix of 120/240 and then the 120/208 circuits from 3 phase power in larger settings. So while most homes may have 240volts available, an office building may only have 208 between any two legs of the three phase power they have. For a computer, it doesn't really matter, but for things like induction motors, it's more of an issue.
From: Jasen Betts on 15 Jul 2010 05:36 On 2010-07-14, Baron <baron.nospam(a)linuxmaniac.nospam.net> wrote: >> How often do people drop dead from actual electrocutions in places >> that use 240, just doing plain tasks like you might at home or >> outside? > > People do die from electrocution on 240 volt AC mains. More often than > not the reflex action causes you to pull away. I agree with your > comment that "the danger is almost always from what you end up hitting > or falling off (like a ladder) /into than from the shock itself." > DC is far more likely to kill you, simply because the muscle contracts > and makes it impossible to let go. AC can do that too, My dad had trouble putting a skilsaw down after cutting the lead. luckily he was able to out-distance the extension lead. Next time he used it with an isolating transformer. --- news://freenews.netfront.net/ - complaints: news(a)netfront.net ---
From: baron on 15 Jul 2010 06:58 Cydrome Leader Inscribed thus: > Sjouke Burry <burrynulnulfour(a)ppllaanneett.nnll> wrote: >> Cydrome Leader wrote: >>> Baron <baron.nospam(a)linuxmaniac.nospam.net> wrote: >>>> Cydrome Leader Inscribed thus: >>>> >>>>> Sjouke Burry <burrynulnulfour(a)ppllaanneett.nnll> wrote: >>>>>> Cydrome Leader wrote: >>>>>>> JW <none(a)dev.null> wrote: >>>>>>>> On Mon, 12 Jul 2010 21:06:30 +0000 (UTC) Cydrome Leader >>>>>>>> <presence(a)MUNGEpanix.com> wrote in Message id: >>>>>>>> <i1g04m$aig$2(a)reader1.panix.com>: >>>>>>>> >>>>>>>>> you can grab a cheap am radio, remove the cover and even just >>>>>>>>> poke around at the parts while it's on. >>>>>>>> Battery powered of course, if poking with your fingers! >>>>>>> haha, yes. >>>>>>> >>>>>>> So what does mains shock feel like in places with 240? >>>>>> It makes you see stars, and makes your muscles contract >>>>>> violently. And there might be a small burn mark. >>>>>> Having good quality plastic soles under your shoes makes single >>>>>> contact oke. Dont use leather soles. >>>>>> My limit fo far is 2X500 volt from a falling radio I tried to >>>>>> catch..... We both survived. >>>>>> Automatic reflexes are so dangerous when you work with >>>>>> electricity. >>>>> Interesting. >>>>> >>>>> Here in US with 120, the danger is almost always from what you end >>>>> up hitting or falling off (like a ladder) /into than from the >>>>> shock itself. >>>>> >>>>> I've never been burned from 120 or seen stars or anything like >>>>> that. I've touched high voltage DC equipment where it doesn't even >>>>> matter if only one hand is in the pocket or or anything like that. >>>>> At 8kV you're getting a one handed shock unless you have special >>>>> boots on. >>>>> >>>>> The last actual line voltage electrocution story from around here >>>>> was from somebody running an electric drill outdoors on a hot day. >>>>> They sweated into the drill, couldn't let go and died. >>>> Possible, but I suspect an urban legend. >>> >>> If the chicago suntimes or tribune had a functional search feature, >>> you could locate the story, but that's a different story. >>> >>>>> How often do people drop dead from actual electrocutions in places >>>>> that use 240, just doing plain tasks like you might at home or >>>>> outside? >>>> People do die from electrocution on 240 volt AC mains. More often >>>> than >>>> not the reflex action causes you to pull away. I agree with your >>>> comment that "the danger is almost always from what you end up >>>> hitting or falling off (like a ladder) /into than from the shock >>>> itself." DC is far more likely to kill you, simply because the >>>> muscle contracts and makes it impossible to let go. >>> >>> Is it 240 from either side of the line to ground, or how does that >>> work? I asked all about this when I was in Ireland, but forgot the >>> answer. >>> >> No,1 phase and 1 return. >> The return is actually the centre tap of the 3 phase system(3 X 240 >> V), and equivalent to ground. > > So it's usually some sort of Wye connection where one side of the > power would in theory br safe to just touch if you were standing in a > puddle? Normally the centre tap is bonded to earth at the distribution transformer, such that the Neutral and earth are at the same potential. The Blue, Yellow, Red phases supply the 240 volt feed. Often you will find that one side of the street is one phase and the other side of the street is another. They do try to balance the phases by connecting equal numbers of homes to each phase. In the UK its rare to have a domestic property supplied with all three phases. > What's confusing in the USA is the mix of 120/240 and then the 120/208 > circuits from 3 phase power in larger settings. > > So while most homes may have 240volts available, an office building > may only have 208 between any two legs of the three phase power they > have. > > For a computer, it doesn't really matter, but for things like > induction motors, it's more of an issue. -- Best Regards: Baron.
From: baron on 15 Jul 2010 07:01
Jasen Betts Inscribed thus: > On 2010-07-14, Baron <baron.nospam(a)linuxmaniac.nospam.net> wrote: > >>> How often do people drop dead from actual electrocutions in places >>> that use 240, just doing plain tasks like you might at home or >>> outside? >> >> People do die from electrocution on 240 volt AC mains. More often >> than >> not the reflex action causes you to pull away. I agree with your >> comment that "the danger is almost always from what you end up >> hitting or falling off (like a ladder) /into than from the shock >> itself." DC is far more likely to kill you, simply because the muscle >> contracts and makes it impossible to let go. > > AC can do that too, My dad had trouble putting a skilsaw down after > cutting the lead. luckily he was able to out-distance the extension > lead. Next time he used it with an isolating transformer. > > > --- news://freenews.netfront.net/ - complaints: news(a)netfront.net --- Nasty ! I'm glad he's OK. I use a GFI on power tool cables. -- Best Regards: Baron. |