Spur off Double Socket.

[JohnW2]

If you have the two single sockets, then the two could be widely separated. Two widely separated sockets, would be much more inclined to be used to maximum capacity - potentially a 3kw heater, plugged into each socket. Much less likely, is two 3kw heaters, plugged into one twin outlet, because they would be so close together.

A theoretical possibility, but I'm not sure why you see it as a problem.

Concerns we hear voiced by some people in relation to "two 13A loads" relate to their both being plugged into the same double socket. Those same people would presumably be happy if the two 13A loads were plugged into two separate 13A sockets, wouldn't they?

I vaguely remember, back in the mists of time, that two single sockets were once allowed to be spurred off one location of a ring circuit???

I have the same vague recollection. Secure could probably remind us!

 

[Harry Bloomfield]

A theoretical possibility, but I'm not sure why you see it as a problem.

Concerns we hear voiced by some people in relation to "two 13A loads" relate to their both being plugged into the same double socket. Those same people would presumably be happy if the two 13A loads were plugged into two separate 13A sockets, wouldn't they?

2x 13amp loads, fed via one 2.5mm, potentially loading one leg of the ring?

 

[EFLImpudence]

I vaguely remember, back in the mists of time, that two single sockets were once allowed to be spurred off one location of a ring circuit???

I have the same vague recollection. Secure could probably remind us!

I thought Appendix 15 was merely 'informative'.

 

[JohnW2]

2x 13amp loads, fed via one 2.5mm, potentially loading one leg of the ring?

In terms of "potentially overloading one leg of the ring", no different/worse from supplying the loads from two separate sockets which were close to one another, or separate spurs from two very-close-together separate sockets or even (as has been discussed) two spurs originating from the same socket.

2.5mm cable would theoretically have to be Method C, but the same would be true if it were only supplying one double socket (unless you believed that 2 x 13A loads would never be plugged into the double socket.

 

[JohnW2]

I thought Appendix 15 was merely 'informative'.

It is, so Harry's use of the word "allowed" was probably wrong. However, I do vague recall similar to him, that there was a time when the guidance (or maybe even a regulation back then?) 'accepted' two single sockets from an unfused spur

 

[EFLImpudence]

 

[pete01]

Didn't read every post but you could downrate the whole circuit to 20 amps...maybe.

 

[ebee]

Indeed. It says ...

... which, apart from seeming generally daft, does not really make much sense to me - what is "an item of stationary equipment connected directly in the circuit" if not, effectively, an 'unfused spur'??

As we know, the OSG seem to have invented all sorts of 'rules' of its own, some more bizarre than others. How about this one? ...

?? -

I will ditto on that. In fact, just to keep it simple, If I had 10 points directly on a ring final (say 10 twin sockets on the ring itself then one (or dare I say 2 or 3) sockets on own radial from the fuseway then another say 10 or so twin sockets connected directly to the ring with junction boxes then that has exceeded the numbers stated but what is the harm.

Or a ring with no sockets directly on the ring itself but 20 or 30 spurred off individually to one twin socket per spur.

I would not actually do either of those types onf thing but I do not see what harm done if somebody decides to.

In fact if somebody made a circuit with a 30A fuse or 30A/32A breaker with as many conductors needed to fill the terminal and each of those conductors is in itself a radial to a twin socket using 2.5 T&E and it is both mechanically and electrically sound then what is objectionable there too? Once again I would not actually do such but merely ask what is the problem?

 

[ebee]

It is, so Harry's use of the word "allowed" was probably wrong. However, I do vague recall similar to him, that there was a time when the guidance (or maybe even a regulation back then?) 'accepted' two single sockets from an unfused spur

I think the guidance perceived the likely hood of one or both of those single sockets could get changed to twin sockets later on and unknowingly at a later date

 

[EFLImpudence]

Yes, that'll be it. Obviously no possibility of changing one twin to two twins.

 

[JohnW2]

I will ditto on that. In fact, just to keep it simple, If I had 10 points directly on a ring final (say 10 twin sockets on the ring itself then one (or dare I say 2 or 3) sockets on own radial from the fuseway then another say 10 or so twin sockets connected directly to the ring with junction boxes then that has exceeded the numbers stated but what is the harm.

Quite so.

Or a ring with no sockets directly on the ring itself but 20 or 30 spurred off individually to one twin socket per spur.

Indeed. Bernard may jump in with his piccie opf just that!

I would not actually do either of those types onf thing but I do not see what harm done if somebody decides to.

For what it's worth, same here.

In fact if somebody made a circuit with a 30A fuse or 30A/32A breaker with as many conductors needed to fill the terminal and each of those conductors is in itself a radial to a twin socket using 2.5 T&E and it is both mechanically and electrically sound then what is objectionable there too? Once again I would not actually do such but merely ask what is the problem?

Again, agreed.

Kind Regards, John

 

[JohnW2]

I think the guidance perceived the likely hood of one or both of those single sockets could get changed to twin sockets later on and unknowingly at a later date

Maybe. Another possibility is that they thought that permitting only one accessory (be it a single socket, double socket or FCU was the most 'foolproof'. In order words,they might have feared that, if a spur were 'allowed' to feed gtwo single sockets, someone in the future finding a single socket on a spur might 'assume' that it was the only thing supplied by that spur, and therefore add 'the second one' (another single socket).

However, in both cases one has to wonder/ask how far we (*regulations) should go to protect against possible incorrect modifications to the installation in the future.

Kind Regards, John

 

[Harry Bloomfield]

2.5mm cable would theoretically have to be Method C, but the same would be true if it were only supplying one double socket (unless you believed that 2 x 13A loads would never be plugged into the double socket.

That is exactly the point I was trying to make - rare would be the need for two sockets adjacent to each other (twin), to need to each supply a full 13amp load. However, that becomes much more likely if two single outlets are separated by distance.

 

[JohnW2]

That is exactly the point I was trying to make - rare would be the need for two sockets adjacent to each other (twin), to need to each supply a full 13amp load. However, that becomes much more likely if two single outlets are separated by distance.

True - but, as I said, if it's Method C 2.5 mm² cable (which is very commonly the case), then the fact that both sockets might (albeit very unlikely) both be simultaneously loaded to 13A for a significant period of time would not matter, would it?

 

[securespark]

A theoretical possibility, but I'm not sure why you see it as a problem.

Concerns we hear voiced by some people in relation to "two 13A loads" relate to their both being plugged into the same double socket. Those same people would presumably be happy if the two 13A loads were plugged into two separate 13A sockets, wouldn't they?

I have the same vague recollection. Secure could probably remind us!

I don't have it with me (I'm away), but I remember in the 14th Ed., something like you could have two single sockets or one double on an unfused spur.