Jihad needs scientists
in [Design]
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From: unsettled on 5 Feb 2007 23:30 Eeyore wrote: > unsettled wrote: > > >>Eeyore wrote: >> >>>unsettled wrote: >>> >>>A ring typically supplies an entire floor/storey of a British home possibly >>>excluding the kitchen. >> >>That's no excuse. > > Excuse for what exactly ? > >>>>US general purpose circuits are mostly 15 amperes at >>>>120 volts, with some 20 ampere circuits for kitchens >>>>with heavy appliance use, and laundries where a washing >>>>machine and gas clothes dryer are connected to one >>>>circuit. >> >>>>We don't do rings for residential power. >> >>>I know. >> >>>>UK puts up to 7 amp fuses in the cord plugs, >> >>>13A actually ( 3kW ). Popular fuse sizes are 5, 10 and 13 amps with 7, 3, 2 and >>>1 amp available too. >> >>Worse than I thought. > Worse how ? I suppose you're worrying about ppl fitting the wrong ( too large ) fuse > ? >>>>approximately the same wattage as our 15 amp branch circuits. >>> >>>>>>Safety in one way, not so very safe in another. >> >>>>>In what way is that unsafe exactly ? >> >>>>Doctor Doctor, what's holding up that brain transplant? >> >>>I see you can't answer the question. >> >>I shouldn't ave to, with your extensive technical knowledge. LOL >>>What do you think fuses are there for ? Hint. It's not to 'protect' the >>>appliance. >> >>They're there to "protect" the wiring. > > Good Lord ! You got one right ! > >>In your case there's >>serious energy at the receptacle, plenty enough to very >>quickly start a fire. >>Your receptacles themselves are not capable of safely carrying >>the current available to them. That's God awful design. If the >>plastic material of the receptacle carbonizes and begins to arc >>there's an awful lot of energy available to star a fire. > You're talking rubbish. They're a vast improvement over those bent bits of metal you > lot use. The only criticism I've ever seen of them is that they could be considered > to be over-engineered. > http://en.wikipedia.org/wiki/BS_1363 > Often considered the safest plug / socket system in the world btw. The only receptacles I saw were the older round prong variety, but no matter, even these are only rated for 13 amperes with 30 amps available. Anyway that's only part of it. Any form of damage or contamination that allows the receptacle to become carbonized can easily lead to an electrical fire. >>We have, at most, 20 amperes at 120 volts in general use >>receptacles, fed by wire that will carry that current forever >>without overheating. And we derate that wire to 80% normal >>(here's a new word for you) ampacity in those cases where >>the circuit will be used continuously for 3 hours or longer. >>UK uses a smaller wire for the ring circuit, counting on it >>being fed from two direction to each load. The wire, by US >>standards, is significantly undersized. Presuming a break >>anywhere in that loop means that the full 30 amperes is >>available to a terribly undersized wire which can then >>over heat to glowing inside the walls and ceilings without >>the protective overcurrent device disconnecting the load. > Why do you presume a break ? Because any time life safety is considered one *must* consider each possible failure to be likely. > The cable used is 2.5 mm^2 btw which is 14 AWG. It's comfortably rated. Do feel free > to calculate temp rise if you feel so inclined. Don't need to. Our electrical code considers 14 gage wire suitable for a 15 ampere intermittent load. > Your understanding of UK wiring is quite flawed. I saw it. I had my hands in it. I didn't like it one bit. > Electrical problems here are exceedingly rare unknown Nonsense. > and it's unheard of for faulty electrics to cause house > fires. Sounds like propaganda. I'd have to see actual statistics on that.
From: MassiveProng on 5 Feb 2007 23:32 On Mon, 05 Feb 2007 22:30:35 -0600, unsettled <unsettled(a)nonsense.com> Gave us: >Anyway that's only part of it. Any form of damage or contamination >that allows the receptacle to become carbonized can easily lead >to an electrical fire. You're an idiot. That remark proves it.
From: unsettled on 5 Feb 2007 23:39 Eeyore wrote: > unsettled wrote: > >>Eeyore wrote: >> >>>unsettled wrote: >>> >>>>Eeyore wrote: >>>> >>>>>unsettled wrote: >>>>> >>>>>>Eeyore wrote: >>>> >>>>>>>Look at the difficulty in getting kids to study science now for example. I'm >>>>>>>sure the kids are right to tend to avoid it since they've seen so many >>>>>>>'scientific' jobs disappear. >>>> >>>>>>Spoken like a tech. Science isn't a "job", it is a calling. >>>>>> >>>>>>Perhaps you meant to say "engineering". >>>> >>>>>I used the term science quite intentionally. Hence the quote marks. Not least >>>>>because that's what politicans here call it. Engineering has become a dirty word. >>>>>There's another problem. >>>> >>>>So what you actually meant is technological jobs? >>> >>>That covers a very broad range. >>> >>>>I was told that a man whose job related education consisted of an solely of an >>>>apprenticeship at Rolls Royce (automobiles) was "an engineer" I almost fell out of >>>>my chair. His "maths" consisted of what we call "shop math" over and above the >>>>regular schooling all children get. >>> >>>I'd say that person was perhaaps a technician but the it's become popular for people to >>>be given more important sounding names for their positions these days. >>> >>>Below the technician in an aero engine company would be a mechanic / fitter >>>historically. >>> >>>I have difficulty explaining to 'average ppl' today what an electronics design engineer >>>does. Typically I'm asked if that means I solder things ! When I say I design circuitry >>>and enter it on a CAD system most ppl look very perplexed. If I mention software, > ppl >> >>tend to ask if that means I do phone support. > >>>>>>>Also, as for Blair's idea that we can do 'R&D' instead of manufacturing, he's >>>>>>>barking mad. Doesn't he know who it is who needs that R&D ? >>>> >>>>>>Once again spoken like a tech. The future needs today's R&D. >>>> >>>>>Of course it's required by companies. Now explain how a country with little >>>>>manufacturing industry can support a large R&D industry. >>>> >>>>Immediately switch from being a socialist economy to a capitalism. >>> >>>Would you care to elaborate how you see socialism and capitalism fitting into the >>> above? In other words which you associate with what ? > Lack of answer noted. Buy some economics books. There is a lot of well written economic theory scattered around the internet. >>>>R&D is an investment just like any other. How can you *not* afford that? >>> >>> >>>I agree in principle but who wants ( can use ) the R&D if there aren't any >>>manufacturing companies ? >> >>The product of R&D is an asset like any other. > > > I know. You still need customers though. R&D isn't a freely tradeable commodity like oil or > corn. Of course any useful work product is.
From: MassiveProng on 5 Feb 2007 23:42 On Mon, 05 Feb 2007 22:39:31 -0600, unsettled <unsettled(a)nonsense.com> Gave us: >Buy some economics books. There is a lot of well written economic >theory scattered around the internet. I doubt that you'll find any chapters on "Toggle Economics". And NO, the reason such a country did that had nothing to do with such a switch.
From: Eeyore on 6 Feb 2007 00:34
unsettled wrote: > Eeyore wrote: > > unsettled wrote: > > > >>Your receptacles themselves are not capable of safely carrying > >>the current available to them. That's God awful design. If the > >>plastic material of the receptacle carbonizes and begins to arc > >>there's an awful lot of energy available to star a fire. > > > You're talking rubbish. They're a vast improvement over those bent bits of metal you > > lot use. The only criticism I've ever seen of them is that they could be considered > > to be over-engineered. > > > http://en.wikipedia.org/wiki/BS_1363 > > > Often considered the safest plug / socket system in the world btw. > > The only receptacles I saw were the older round prong variety, 40 years ago ? > but no matter, even these are only rated for 13 amperes with > 30 amps available. 15A actually. > Anyway that's only part of it. Any form of damage or contamination > that allows the receptacle to become carbonized can easily lead > to an electrical fire. In order for anything to carbonise it has to get hot. The BS1363 plug only carries 13A though a solid machined contact unlike the 15A you put through your bits of bent metal. Ir doesn't get hot ! > >>We have, at most, 20 amperes at 120 volts in general use > >>receptacles, fed by wire that will carry that current forever > >>without overheating. And we derate that wire to 80% normal > >>(here's a new word for you) ampacity in those cases where > >>the circuit will be used continuously for 3 hours or longer. > > >>UK uses a smaller wire for the ring circuit, counting on it > >>being fed from two direction to each load. The wire, by US > >>standards, is significantly undersized. Presuming a break > >>anywhere in that loop means that the full 30 amperes is > >>available to a terribly undersized wire which can then > >>over heat to glowing inside the walls and ceilings without > >>the protective overcurrent device disconnecting the load. > > > Why do you presume a break ? > > Because any time life safety is considered one *must* consider > each possible failure to be likely. I dare say it's been considered. Rules for ring circuits say that the cable rating must be no less than two thirds of the rating of the protective device. This means that the risk of sustained overloading of the cable can be considered minimal. In practice, however, it is extremely uncommon to encounter a ring with a breaker other than 32 A and a cable size other than those mentioned above. http://en.wikipedia.org/wiki/Ring_main > > The cable used is 2.5 mm^2 btw which is 14 AWG. It's comfortably rated. Do feel free > > to calculate temp rise if you feel so inclined. > > Don't need to. Our electrical code considers 14 gage wire > suitable for a 15 ampere intermittent load. So does ours it would seem. > > Your understanding of UK wiring is quite flawed. > > I saw it. I had my hands in it. I didn't like it one bit. > > > Electrical problems here are exceedingly rare unknown > > Nonsense. It's a fact. If you know of some please post a link. > > and it's unheard of for faulty electrics to cause house > > fires. > > Sounds like propaganda. I'd have to see actual statistics on that. It just doesn't happen unlike the conflagrations you guys get. The British system is simply far better engineered. Graham |