If you wire a plug up with the neutral and earth reversed, it will take out the RCD supplying that circuit, which in turn will take out every other circuit supplied by that RCD. The fuse in the plug will remain intact.
Well, this is something of a spurious argument Frank. Fuses generally only fail if the lamp blows and lamps usually blow when you first switch them on from cold or if you give them a good knock when they're hot.
Lamps rarely blow in the middle of a show and you wouldn't stop the show to change a lamp, so whether or not the plug top is fused is beside the point.
The reason theatres have 15A BS546 plugs and sockets is because they pre-date BS1362 plugs and sockets and, as there was and is no safety-related need to implement fused plugs, they never have been implemented.
: > : > : > : : > : > : Never mind - it'll ne OK when you finish Key Stage 2. : > : >
: > : > Just because you are still at Key Stage 1, repeating, : > : > unquestioned, all your are being told parrot fashion, you : > think : > : > everyone else is... : > : : > : just because you have fished stage 2, don't assume that those : > of us with : > : degrees in electrical engineering and a lifetime of dealing : > with : > : electrical circuits haven't thought about it just as much as : > you have, : > : and don't need to be patronised. : > : : >
: > Just because you have learn to act like parrots, repeating : > ad-nausea what your owners tell you, rather than use your brain : > cells... It was people like you who held industrial : > manufacturing/development in the UK back for so long, allowing : > others to have the blue "skies thinking" that turned much of the : > UK Plc into not much more than assembly lines at best and : > importing/warehousing agents at worst. : > -- : > Regards, Jerry. : : 99% of major innovation has come from the UK (or Germany) The Yanks : invented nothing new.
Very little is "new", hence the saying "What goes around comes around", what makes (or looses) money is how it is done.
: I have walked round construction sites in America. It's like going : back to the 1920s. And the standard of work was total crap.
Indeed, and I have lived in modern UK built dwellings were one faulty appliance trips out the whole frecking power for the dwelling! I've also lived in (then, un-modernised) pre-war dwellings that were better built than their modern equivalent. Put it this way, the serious operational failings found with ring circuits almost certainly stops them being used on safety critical circuits. The problem with North American electrical instilations is not the circuit diagrams/layouts but the quality of the materials used.
: Your wiring systems date from the early 20th century. Your plumbing/ : heating systems are even worse.
Talking about yourself, you most certainly are not talking about myself...
: Have you ever been here?
Fortunately not, unlike you I don't need to be a pizzle, living in Neverland, with a "Nanny-on-line" (aka AOL) ISP account and be a Google groupie...
Try actually using your brain cells Harry, your arguments against radial circuits seem to be simply built on what 70 years of urban-myth and crap materials found in North America.
: The regs, if followed, will protect everyone from bad : installation. They might not, and should not attempt : to IMHO, protect you from yourself.
No, surely the regs should protect *everyone" from either bad instillation OR from what others have done (try reading the first rule in the H&S regs, or are you suggesting that H&S rags should be scrapped...), and as there is nothing dangerous about radial circuits or their installation - if they were they would be outlawed by the regs, which they are not...
: I can think of numerous devices that come with various : gizmos to adapt them to a number of plug styles, rather : than pre-fitted or moulded-on BS plugs.
Yes, some products do come with a (typically) moulded on euro-plug plus a BS1363 adapter plug, the point being is that these adapters do not require the plug to be 'wired' [1], the europlug simply plugs into the adapter.
[1] to stop people from miss-connecting, for example, connecting the either wire to the neutral and neutral to the earth.:
Yes, YOUR hatred against anything you either have been told is not 'correct' or what you don't understand is indeed a Strew Man...
There is only one reason for laws and regulations, to protect, if you are claiming that one system is no more safe than any other you are suggesting that there is no need/point in having any regulations in the first place!
: >
: > Bollocks, it only need metal the same dia of : > the BS fuse,
: How many people do you know who would go to : the bother of finding a bolt of the correct diameter
Someone who doesn't have a replacement fuse at a time when (for what ever reason) they can't not purchase the correct fuse, or even the incorrect fuse but - believe - they have to have the appliance operational...
: and cutting it to length just to avoid fitting a fuse? : An incorrectly rated fuse is a far more likely scenario.
Indeed, such as a piece of copper wire fitted along-side the blown BS fuse...
: > Another unthinking parrot, "the regs say such and such, so that : > is that then"... : : Whatever you say, Jerry. : : I'm minded of the proud mum watching her army son marching with all his : fellow squaddies. 'Ooh look! My son's the only one in step......' :
Well yes, the regulations/Sergeant decreases something and from that day on that is the only way what-ever can be safely achieved...
: > > Another unthinking parrot, "the regs say such and such, so that : > > is that then"... : >
: > Whatever you say, Jerry. : >
: > I'm minded of the proud mum watching her army son marching with all his : > fellow squaddies. 'Ooh look! My son's the only one in step......' : >
: : We're talking about a Yank here. They don't even get a proper : education.
Is "The Wanderer" a Yank then, or were you talking about yourself again "Harry", what with your AOL account and all that?!...
"John Rumm" wrote in message news: snipped-for-privacy@brightview.co.uk... : On 02/09/2010 21:51, Jerry wrote:
: >
: > Oh, so taking out just a room rather than a floor (as is usual : > with a ring circuit) is worse?! : : Oh so taking out a room, rather than just the plug fuse for the : appliance in question is better? :
No, but we were talking about faults that DO trip the D-board protection, that said it is FAR better just to take out one room than a whole floor/all power in the dwelling.
: >
: > : : > :> The ONLY two advantage of ring circuits is installation cost : > and : > :> smaller size of fuse/CB panel. : > : : > : In fact neither of these are true now. Installation cost, when : > : installing from scratch is not significantly different. : >
: > But was when the UK ring circuit was first designed and : : It was by virtue of it allowing adaptation and re-use of existing wiring : - two 15A circuits could be combined into one that could reasonably used : to heat a storey of a property. If laying in cables from scratch there : is not much in it. : : > introduced, now the ring has just become the day-facto standard : > and is often installed without (prior) thought. : : Given it has proved its versatility and safety, then that is probably a : good thing.
But radials were also common in the 1950s, they were (and where they still exist, are) safe, most will have had modern sockets fitted and as such have the one advantage (local/final protection of the appliance) of the BS1363 plug but without the possibility of gross abuse that is possible when used on ring circuits.
: : > Also remember : > : than in the UK we can have 32A radial circuits if required, so : > there is : > : no particular advantage in reducing the number of ways in a : > consumer : > : unit either. : >
: > But the use of ring circuits HAS resulted in a reduction in the : > number of ways in the average domestic D-board. : : Compared to what? : : 40 years ago a domestic house probably had a four or five way board if : you were lucky. These days 8 - 12 is more common.
Yes, and that is for ring circuits!
Lets look at what could be a typical radial circuit instillation, take the average modern 4 bed (CH installed) two floor family house with a living, dinning, study. Dealing with just the power circuits most dwellings will have no more than two ring circuits (perhaps three if it's thought that diversification will be insufficient in the kitchen/utility room), plus a circuit each for emersion heater, cooker feed, shower - that equates to SIX power circuit protection devices at the D-board. Now lets take the same dwelling that has been fitted with radial circuits through out, we will need at least one protection device [1] (@15A) for each bedroom, the living room, dinning room, study, hall + landing - that is NINE circuit breakers (allowing for two double sockets in each room) without even considering the kitchen or other currently installed radial circuits, one could easily get close to needing a 15 to 20 way D-board JUST for the power circuits. This is the only advantage of ring circuits, but only then at installation, and of course architects and builders would have to think were to site such a D-board - no more just bunging it behind the swing of the front door in the entrance hall...
[1] yes, diversification *might* be possible between some rooms: : >
: > : : > : It is important to realise that what started as a way of saving : > copper : > : after the war, has been refined and improved over the years, to : > what we : > : have now, which is a circuit that is very well suited to modern : > patterns : > : of use. : >
: > Has it been refined, *circuit* protection might have been refined : > and this has allowed a refinement in conductor size etc. but the : > circuit design and end appliance protection hasn't been refined : > that much if at all. : : The basic circuit design is similar (but much more research has been : conducted into understanding de-rating factors resulting from cable : grouping, ambient temperature, installation method etc, and into : understanding the appropriate limits to circuit length (due to voltage : drop or earth loop impedance)). Cable earth conductor sizes have been : changed in places, and fuses have generally be replaced by dual acting : miniature circuit breakers. RCDs are now used extensively. : : What has changed massively is modern usage. : : A few years ago I rewired a neighbours house. It had its original wiring : as installed in the early '50s (plus a bit of bodging from the owner!). : It was instructive to see what constituted a typical electrical : installation. : : There were four circuits in total - two lighting, two power (the power : circuits were radials wired in rubber sheathed cable with a separate : bare earth wire). Each power circuit fed approx 4 sockets - giving a : total of 9 for the whole house (and these were all single sockets). : : When we designed what was needed for their actual usage, we ended up : with something like 34 double sockets. That was three rings (upstairs, : downstairs, and kitchen), two lighting circuits (one per floor), and : high integrity radial with its own dedicated higher threshold RCD for : the freezers, CH boiler, and fish tank, plus a sub main feed for the : outbuildings. : : One could have slapped in a a few extra radials for each floors sockets, : but it would have added little of any great value. Its unlikely the : circuit breaker for any power circuit will ever trip. If the CH fails, : and they want to plug in a couple of 3kW heaters, then they can do that : pretty much anywhere, without fear or tripping something.
Hmm, with a separate radial circuit to each bedroom it would be possible (within the limit of the company fuse...) to have a 3Kw fire in each bedroom, one will start having problems trying to do that with the typically wired ring circuits found in the average modern house.
Meanwhile : should a wire work loose somewhere, there is a reduce chance of : overheating of loss of earthing due to the redundancy of the ring circuit.
Bollocks, with respect, the same loading could be applied to the faulty circuit, that could well mean that the one 2.5T&E will be taking the full 30A load (your ideal failure would *have* to be exactly half way around the ring, so not to unbalance the circuit)... If the same wire came loose within a radial circuit it would either fail completely or the serious fault would be very evident to all by the terminally and literally mentally clueless.
: : > The ring circuit is also well suited to provision of power for : > : "diverse" loads - i.e. large numbers of appliances can be : > provided for : > : over a large floor area, and also higher power devices can be : > included : > : in that mix without fear or overloading a circuit. : >
: > Err, one can only use, either, the number of appliances up to the : > total number and rating of sockets or the total rating of the : > circuit, the same is true of radial circuits. 'Diversity' is : > applicable to the loading of radial circuits as it is to ring : > circuits. : : Diversity applies to both, however the more floor area covered, and the : more appliances in question, the more diversity there is.
Only if there is sufficient ring circuits, the average new 'system/price' built house will often only have bare necessity. Most people do *not* live in that perfect world called utopia.
: : > Alternatively they : > : also cope with applications where many high power appliances : > are used in : > : proximity such as kitchens, where the ability to provision for : > 7.2kW of : > : load without needing unmanageable cables sizes is a great : > advantage. : >
: > Sorry but that sounds somewhat like a straw-man argument, how : > many domestic kitchens would draw that sort of (non "diverse") : : Domestic kitchens with an appliance load of 9 - 12kw are common here. : Most will have dish washer, washing machine, and drier, and each of : those will often pull 2 - 3kW. On top of that many single ovens up to a : couple of kW are designed to "plug in". A kw of microwave, and on top of : that you will usually have a few "small" appliances like a 3kW kettle, : and 2kW toaster etc (you can ignore those from loading calcs since they : are such short term loads). There will often be dedicated 32A or 40A : radials for cooker supplies where electric cookers and hobs are installed.
But as you say, most if nor all have more than one circuit supplying the kitchen, thus one is having to build diversity into the instillation anyway...
: : (its worth noting that the easy availability of a 3kW supply to an : appliance means the appliances available and commonly used are different : from in some countries. So in places like the US electric kettles are : much less commonly used due to lack of power, and "wet" appliances : usually have hot fill etc to save needing to heat water locally and : slowly etc). : : : > load [1] and if we are talking about industrial installations : > then running radial circuits via a sub-main and sub-board could : > be as convenient, with the added advantage of appliance : > redundancy - not having the one out all out total failure of a : > ring circuit tripping out. : : Again we keep coming back to "rings tripping out". As a general rule not : something that happens with great regularity.
In the perfect world it will never trip out, or would any radial, the problems start *when* it does.
: : The most common "trip" problem we tend to get here is with RCD trips : caused by faulty appliances (or damaged wiring). Neither of which are : going to benefit from being ignored from prolonged periods.
Indeed, but if the appliance is being feed via a radial it can
*often* be ignored - in so much as the circuit being left isolated until such time (when ever that is), with a ring one has to deal with fault by either correcting the fault or by removing the appliance for the circuit unless one is prepared to have everything feed from that ring circuit isolated also.: : > [1] and as has been pointed out elsewhere, if 7.2KW of non : > diverse load does need to be supplied then 2/3rds of the cabling : > needed for three radial circuits would be needed in a dedicated : > ring circuit anyway. : : yes, and?
I was merely pointing out that the only saving between three separate radials and one ring circuit was a length of wire and a couple of CBs in the above scenario, in other words we're back to arguing instillation costs.
: : > : You have a circuit that behaves better under most of the common : > failure : > : modes in circuit wiring (i.e. high resistance or broken : > conductors), and : > : retains higher levels of protection under most of these failure : > modes. : >
: > In other words, what you seem to be saying is, the ring circuit : > is good at masking (possibly) fatal faults, such as a : > disconnected conductor, thus the circuit has the same load on a : > single 2.5mm T&E rather than sharing the load between two sets of : > such conductors... : : The most common fault is a high resistance connection (loose screw : terminal etc). You will tend to get less serious overheating on a ring, : and usually no increase in fault disconnection times. : : The next most common fault is a broken earth conductor (its thinner and : uninsulated), again a ring carries on safely while a radial will have a : proportion of its sockets without any earth.
Not sure if we are getting close to a strew man argument here, surely the most common point of such failure is at the mechanical joint(s) and as such both conductors could - if not would - fail at that point, thus in both a ring and radial circuit if it is a positive or neutral conductor fault then that socket is likely to stop working (or worse still, become intermittent under load) but on a ring every other socket will carry on regardless, on a radial anything down-stream of the fault will also fail. In the above earth conductor fault occur then that socket will have lost it's earth with either ring or radial circuits. I can accept that there is an added (theoretical) risk on radial circuits should the earth conductor fault occur, not only would the socket in question have a earth fault but any socket down-stream would too.
: : The next most common is a broken live or neutral conductor. Here a ring : *can* mask the condition where it should be apparent on a radial. : However on most real world ring circuits you would still probably get : away with a fault like this without anything serious happening.
Well yes, but in most modern real world faults, what with the typical double insulated, low consumption, devices in used today, many faults can go undetected for years, but is that really the point, if it is then what's with all the regs...
: : Needless to say you can't always have the best of all worlds, so it seem : preferable to me that you use what performs best with the most likely : faults and that is the ring circuit.
So you advise the masking of *possibly* dangerous faults, that is what you seem to be saying? Cough! :~)
: : > : For a full description see: : > : : >
: > Why should that be, and what would need to be changed in a radial : > circuit spec to mirror the results found in ring circuits? : : A radial will typically be wired in 2.5 or 4mm T&E, both of which have a : 1.5mm CPC (earth), a ring in effect has two of them in parallel. Hence : the fault loop impedance tends to be lower on the ring due to the area : of copper involved. : : Radials can be wired with what is called high integrity earthing - here : the CPC is returned to the origin as if it were a ring, and also the two : earth connections to each socket are made to independent terminals on : the socket. This system is usually specified for when it is known there : will be high earth leakage currents - typical with lots of IT or other : electronic kit where there are lots of mains input filters sticking : capacitors between line and earth.
Cheers for that.
: : With regards dealing with the effects of loose connections, there is not : much you can do with a radial intrinsicly to improve it, other than : specify more frequent inspection and test, and to ensure a good standard : of workmanship is maintained during construction. :
Surely all it would just require is the installation of a return earth, either via a new spec of 4 core cable (T&E[x2]) or a separate earth wire run along side, either method would add little to the work or cost of instillation of each radial circuit - yes it will cost more, radials circuits do cost more, I've already conceded that point. :~)
PS, sorry for the delayed replies.
We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "Jerry" saying something like:
LOL! Spectacular grabbing of the wrong end of the stick, by Jerry. Nothing new there, then.
"Grimly Curmudgeon" wrote in message news: snipped-for-privacy@4ax.com... : : We were somewhere around Barstow,
: Nothing new there, then.
No "Grimly" there is nothing new or changed about *your* attitude, you are still the same old troll, unable to think anything other than what you have read via Google or Usenet. :~(
There is nothing wrong or dangerous about using radial circuits, the same can't be said about many aspects of the typical ring circuit, only UK building convention over the last 60 odd years has made ring circuits the day-facto installation for domestic dwellings (mainly due to cost). I doubt that "Grimly" have ever lived or worked on a radial instillation...
snipped-for-privacy@s9g2000yqd.googlegroups.com...
I never made such a claim. I merely pointed out that NO ONE in this thread had made a claim that ABUSING a system was safer, in response to your strawman question "How is ... being able to protect their 3amp table lamp via a bolt ... any more safe than ..."
Faulty logic, on your part, there..
MBQ
snipped-for-privacy@m15g2000yqm.googlegroups.com...
Glad to see you agree that they are not theer to protect idiots deliberately abusing the system from themselves.
Not dengerous per se, but they can be just as dangerous if an idiot starts messing with them.
MBQ
: > No, surely the regs should protect *everyone" : > from either bad instillation OR from what others : > have done (try reading the first rule in the H&S : > regs, or are you suggesting that H&S rags should : > be scrapped...),
: Glad to see you agree that they are not theer to : protect idiots deliberately abusing the system : from themselves.
But I don't. Forget the idiot, think about those that follow. Tell us, do you check every BS1363 plug for the fitment of the correctly rated fuse before using the appliance or do you assume (like most do) that the correct fuse if fitted?...
: > and as there is nothing dangerous about : > radial circuits or their installation : : Not dengerous per se, but they can be just as : dangerous if an idiot starts messing with them.
Not unless they use more than a kitchen knife, at least on a modern rCB D-board, unlike ring circuits (protected at twice the rating of the average radial circuit) and the current trend of moulded-on BS1363 plugs...
: > There is only one reason for laws and regulations, : > to protect, if you are claiming that one system is : > no more safe than any other : : I never made such a claim.
Liar. If you are not a liar then you are proving that you do not understand the difference between the final protection fitted to a radial and a ring circuit...
: > you are suggesting that there is no need/point in : > having any regulations in the first place! : : Faulty logic, on your part, there..
But it is you who seems to be arguing that allowing the easy bridging out of the final protection device before the appliance is safe.
Indeed there was a time when RCDs first became popular that they were fitted to protect a whole installation. Its a deprecated practice now of course, but there are still some out there.
That's twaddle. The operations failings of radials actually pose a higher risk is a non interruptible supply is of critical concern.
True, and also the fundamental problem of 120V supplies. The higher currents involved and the low quality of fittings combine to more fault prone installations. (the use of ali cable in domestic installs does not help either)
We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "Jerry" saying something like:
Ooh, Jerry's found some new words. From somewhere else on the web, I've no doubt.
That'd be a mega-whoosh, then. Now, pay attention, for I shall write this only once - the wrong end of the stick I referred to was the poster using AOL, who you wrongly assumed was an American poster. Nothing at all to do with ring v. radial circuits, or even anything electrical. You can go back to your Big Boy's Colour Illustrated Book of Electricity (vol 1, 1957) now Jerry, and try to absorb some more of that fascinating theory. Oh, and keep banging those rocks - finally something might fall into place.
: >
: > Indeed, and I have lived in modern UK built dwellings were one : > faulty appliance trips out the whole frecking power for the : > dwelling! I've also lived in (then, un-modernised) pre-war : : Indeed there was a time when RCDs first became popular that they were : fitted to protect a whole installation. Its a deprecated practice now of : course, but there are still some out there.
I was talking about a time when RCDs were not even fitted, just the (then standard) wire fuse...
: : > dwellings that were better built than their modern equivalent. : > Put it this way, the serious operational failings found with ring : > circuits almost certainly stops them being used on safety : > critical circuits. The problem with North American electrical : : That's twaddle. The operations failings of radials actually pose a : higher risk is a non interruptible supply is of critical concern.
Says who, the 16th/17th edition...
Put it this way, if you had to spec the instillation for something like dialysis (or other life/system critical) machines would you be happy with them being on a ring circuit were they could all be tripped out by any fault on the circuit or would you prefer it to have a dedicated supply (in effect a radial circuit) to each machine?
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.