I want to remove a 3 pin round lamp socket - how??
- Thread starter Sleebagz
- Start date
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I don't think the regs. provide for BS4343 sockets on a ring final, whether a spur or not, do they?
Yes - but, again, you are presumably talking of 2A maximum supply at 5V. There's surely no way that something supplying 2A at 5V would 'draw' 2A from a 230V supply?! One expects some 'inefficiency', but that would be ridiculous!
Kind Regards, John
No. You will have seen some debate as to whether it means 'only' BS1363 accessories, but BAS's argument that such would seem to be the obvious interpretation seems fairly compelling. Were that no the case, there would be no need/point in the reg mentioning BS1363 accessories at all. Indeed, as I've said before, I suspect that one of the main reasons they did mention such accessories was specifically to prevent sockets such as you mention being used on a ring final.
Kind Regards, John
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If one forgets 'informative' Appendix 15, then the regulations themselves seem a bit daft. There appears to be nothing in 433.1.204 itself which says that one cannot wire 'dozens' of sockets to an unfused spur (with cable of CCC ≥20A) and, by implication, still enjoy the dispensation to not to be required to satisfy 433.1.1 in the usual way.
Kind Regards, John
Isn't that a bit like saying that there is nothing in the regulation that apples to vehicle lighting, that states you have to drive safely?
Depends on how exactly it's worded these days, I would think. If everything, including ring circuits and spurs therefrom were required to satisfy the basic rules about the protective device not exceeding the cable rating etc. then the regs. would be contradictory in then allowing ring circuit cables to be rated for only 20A and in allowing a double 13A socket to be connected at the end of a spur.
So just how much exemption from these basic rules does the current wording give?
So just how much exemption from these basic rules does the current wording give?
There are two of them.
The 20A is in excess of half the 32A
The spur cable is rated at 27A.
The ring circuit stipulations do not apply to the spurs.
Was just a little bit of joke from me of what one could theoretically do, now of course feeding a 32A socket from a spur using 2.5mm² T&E is a really bad and stupid idea! let alone being obviously non complaint with BS7671.
Not sure what point you're making there about half of 32A?
You mean the current regs. specify that the cable used for the spur must be rated at no less than 27A after applying any correction factors for bundling, ambient temperature, etc?
The cable used for the spur must have an Iz ≥ Ib.
Although little known, the Ib for a DSO cannot be more than 20A, which, coincidentally,
is the minimum Iz required of the main ring final cable.
Two single sockets would give you an Ib(max) of 26A.
Although little known, the Ib for a DSO cannot be more than 20A, which, coincidentally,
is the minimum Iz required of the main ring final cable.Two single sockets would give you an Ib(max) of 26A.
Of course it can, if somebody plugs in two loads which total anything up to 26A. As discussed earlier, while the BS1363 tests may be based around an assumed 20A load, that doesn't mean that two 13A loads can't be plugged into a double socket. And as you remarked, there are some makes of double socket which the manufacturer is clearly saying is designed for that.
Ib is design current, and does not change if someone plugs in 2x13A loads.
I take the point about some DSOs being able to cope with 26A, but I would say that to design around that, particularly in an installation under the control of an Ordinary Person, would not count as exercising reasonable skill and care.
I take the point about some DSOs being able to cope with 26A, but I would say that to design around that, particularly in an installation under the control of an Ordinary Person, would not count as exercising reasonable skill and care.
O.K., call it design current if you like, but when you have two 13A sockets at the end of the cable, there is simply no way to guarantee that somebody won't plug two 13A loads into it at some point. Doesn't this rather illustrate the rather lax attitude BS7671 (and the IEE Wiring Regs. for years before they became BS7671) has toward possible overloads on a ring circuit and associated spurs, in comparison with radial circuits?
"If you like"? It's not a whim of mine - that really is what it stands for.
If you have a final circuit with 20 sockets on it there is simply no way to guarantee that somebody won't plug 20 13A loads into it at some point.
I'm not a fan of ring finals, and I would like to see them deprecated in a future edition of the Wiring Regulations, even though that would inevitably prompt some people to argue that of course it's still OK to install them as they were OK yesterday, there's no requirement to remove them and anyway you've already got them in your house.
But can you explain why a 32A ring can be overloaded but a 32A radial cannot?
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