Spur with two sfcu on it

[Lighting]

Hi all is this ok to run two sfcu like this ?


Or should i run it like this

 

[ezzzekiel]

No it's not your right it's fused at 3a which still makes the circuit correct
everything from the fcu in picture one is limiting the draw to 3a

 

[mickys86]

Either option would be ok unlimited outlets allowed as the first fcu limits the total draw to 13a from that leg of the ring

That's what I was thinking at first but if second spur was connected to supply side of first spur then it would be wrong.

Why is everyone getting uptight about this?? It's Sunday..... Chill day

 

[pencilpusher]

No it's not your right it's fused at 3a which still makes the circuit correct
everything from the fcu in picture one is limiting the draw to 3a

OK but he stated it would be "looped". I take it that means the second FCU is fed from the supply of the first FCU and not the load side. That would mean the 3 amp fuse would protect the light and not the spur cable and that the second FCU could draw up to 13 amps?? That's my take on it but I may have read it wrong.

 

[ezzzekiel]

Yes but then the circuit wouldn't be wired correctly so not a design fault, not uptight about it but to say the circuit is wrong is not true, it may not be ideal or suitable for the use intended but it is correct as far as design goes, outlets are unlimited from fcu taken from the ring as the fcu be it 3,5,13a will limit the loading from the leg to the rating of the fuse.

As PP says above looping would be incorrect but ops original post was just a block diagram

 

[pencilpusher]

Guys, I think this is interesting even if some do not! I am certainly not uptight about any of it.

 

[mickys86]

Not saying you was uptight....but there was a few others.... I never said pic 1 was wrong but I came round to taffys way of thinking.

I can't remember seeing he was going to loop the fcu's I may have read it wrong too

 

[pencilpusher]

Hi all right the socket is on a ring final then going to the 1st sfcu then looping out to the 2nd sfcu o know you can only have 1 socket off a spur but both sfcu will be at 3a so i don't think i need a sfcu by the socket.

Looping! :smile5:

 

[ezzzekiel]

Maybe taffy was thinking that way too which would explain why he said 26a could be drawn, however just going by the ops drawing there is nothing to suggest it would be looped through so in my opinion it was worth 5 pages just to clarify the point that,
yes his circuit is correct providing he wires from the load side of the fcu and not looping from the feed.

Everybody happy with the clarification now?

 

[mickys86]

Maybe taffy was thinking that way too which would explain why he said 26a could be drawn, however just going by the ops drawing there is nothing to suggest it would be looped through so in my opinion it was worth 5 pages just to clarify the point that,
yes his circuit is correct providing he wires from the load side of the fcu and not looping from the feed.

Everybody happy with the clarification now?

Another pint please barman

 

[pencilpusher]

I am always happy! I think it was worth it because he was clearly going to loop from one to the next. If he now understands, then it's sorted.

 

[TaffyDuck]

Maybe taffy was thinking that way too which would explain why he said 26a could be drawn, however just going by the ops drawing there is nothing to suggest it would be looped through so in my opinion it was worth 5 pages just to clarify the point that,
yes his circuit is correct providing he wires from the load side of the fcu and not looping from the feed.

Everybody happy with the clarification now?

It clearly says 3amp to light, 3 amp to boiler so obviously FCU 2 is not fed from the fused side of FCU1. Dont want to go on and on about it but pic 1 IS wrong, Pic 2 is OK. According to both the regs i have listed and your picture of App 15 which clearly shows that Pic 1 is wrong.

 

[ezzzekiel]

It clearly doesnt show any connections at all its a block diagram from which you assume he meant looping from feed and i assume he meant from load

 

[yellowvanman]

Appendix 1 is normative and is thus a requirement. All other appendices are informative, and are provided as guidance.

page 276 of BGB

 

[ezzzekiel]

Did not know that

 

[D80]

Spurring 1 Double socket can draw up to 26 Amps, what is wrong with 2 FCU's drawing a max of 3 amps each?

Or has the ability to use some common sense been lost? 50+ posts on this now, its making a big deal out of something that isn't.

Just what the DIY'er does to alter things at a later date isn't really anything to do with this, they can and do bodge up anything, nothing to stop them spurring of a perfectly good ring final circuit and running several points of that either.

 

[ezzzekiel]

As you say even if the two 3 a fuses were replaced with two 13 a they would still only let the max 26 a allowed from a socket taken direct from the ring

 

[Snapester]

First drawing isn't wrong though as its designed on 6amp max load, the OP should label up max fuse size that should be replaced if it blows in future. But on saying that i do see where Taffy is coming from now and i do agree that if the fuses were replaced with 13a ones then this would show an overload of the cable.
Interesting........

 

[D80]

First drawing isn't wrong though as its designed on 6amp max load, the OP should label up max fuse size that should be replaced if it blows in future. But on saying that i do see where Taffy is coming from now and i do agree that if the fuses were replaced with 13a ones then this would show an overload of the cable.
Interesting........

Why would it be any different at all to a double socket being added?

 

[ezzzekiel]

I agree very interesting topic, especialy as bs76 allows a two gang capable of 26a spurred directly

 

[pencilpusher]

Very interesting, especially as I can only add a single gang socket and not two, one spurred from the other! That would still be a max of 26 amps!

 

[ezzzekiel]

Reason being someone could change the two singles for two doubles at 52a but that could be said for any circuit altered for what it wasnt designed for

 

[pencilpusher]

Agreed and precisely what D80 stated then. What someone else does is nothing to do with this. It can't be OK to quote it just when it suits.

 

[ezzzekiel]

So the question remains would you if looped from feed in side feed two 3a fcu for a max draw of 6a? Providing circuit was clearly identified and certified then although maybe not a standard circuit arrangement still suitable for purpose

 

[TaffyDuck]

D80 the OP was asking which one. Pic 2 is clearly best practice as it complies entirely with Regs. Pic 1 doesn`t. the rights and wrongs of it, whether its safe or not ,which Pic 1 will be on current load, wasn`t the point. He asked which way to do it, I suggested the way that complies with App 15, others disagree and thats fine.

 

[pencilpusher]

I would do picture 2 as well. Night all.

 

[ezzzekiel]

Given that it was later added that it was a ring circuit not a radial and looped from feed in side not load then yes pic two would be the obvious choice, but we are not talking about that we are talking of the suitability of non standard circuit arrangements - or trying too

 

[D80]

Just out of interest, what exactly is the the danger in adding 2 3A FCU to the ring? If situation ever arose that I needed to do it I'd be more than fine with it. I'm sure the OP is lost now as to what to do after 66+ posts, but either option initially posted seems fine to me, the 2nd is a little overkill.

If we are all worried about what the incompetent person may do after us then 32Amp ring are out, may as well do 10Amp radial to cover for them. Don't want to have them adding a shower to the ring after all! I don't care much what someone adds after me, that's their problem. Common sense seems to have long gone here.

 

[TaffyDuck]

Just out of interest, what exactly is the the danger in adding 2 3A FCU to the ring? If situation ever arose that I needed to do it I'd be more than fine with it. I'm sure the OP is lost now as to what to do after 66+ posts, but either option initially posted seems fine to me, the 2nd is a little overkill.

If we are all worried about what the incompetent person may do after us then 32Amp ring are out, may as well do 10Amp radial to cover for them. Don't want to have them adding a shower to the ring after all! I don't care much what someone adds after me, that's their problem. Common sense seems to have long gone here.

At no point have I said Pic 1 was dangerous, just not compliant. Guess the acid test is if this question was in an exam what would your answer be Pic 1 or Pic 2 ? . And this nonsense about the boiler SFCU being fed from the fused side of the 1st SFCU is just folks back pedaling. Or does anyone think its a good idea to have the boiler turn off when you turn the light off?

 

[mickys86]

At no point have I said Pic 1 was dangerous, just not compliant. Guess the acid test is if this question was in an exam what would your answer be Pic 1 or Pic 2 ? . And this nonsense about the boiler SFCU being fed from the fused side of the 1st SFCU is just folks back pedaling. Or does anyone think its a good idea to have the boiler turn off when you turn the light off?

Not back pedalling at all. I made a simple mistake of thinking the whole circuit was fused at 3a. I quickly realised my mistake and then admitted you was right.

 

[TaffyDuck]

Not back pedalling at all. I made a simple mistake of thinking the whole circuit was fused at 3a. I quickly realised my mistake and then admitted you was right.

Not talking about you mate. My previous posts in other threads have several incidences where I have realised I may be wrong and admitted the fact as you did. None of us are perfect , we all get it wrong sometimes. We`re on Page 7 because others wont admit it.

 

[Deleted member 26818]

From what the OP has stated, the first picture is incorrect.
To comply with BS1363, double socket-outlets are tested at 20A, single socket-outlets and FCUs at 14A.
The fact that 3A fuses are installed, is no guarantee that they may not be changed. (Code C2 on a PIR.)
You might get away with permanently marking the FCUs, indicating that 3A is the maximum allowed.

 

[pencilpusher]

That's why I love this forum. So may differing interpretations of the Regs. One says we cannot worry about what people do after we leave and another says they could be changed for another fuse rating. No criticism against anyone here at all but still very interesting all the same. I still say picture 2 is the one I would do. That way, anything after the 13 amp FCU is restricted. "They" can then do what they want.

 

[Deleted member 26818]

These particular fuses are consumables.
They are intended to be replaced by ordinary persons.
As such you as the installer will have no control over whether someone replaces the 3A fuse with a 13A fuse.
It's one of the argumants used for the ban the BS3036 lobby.

 

[ezzzekiel]

Given that it is a ring final and not as thought a radial then as said Taffy is CORRECT AND APOLOGIES to him for any confusion.

Discussion on wether 6a draw from the ring being acceptable although not being a standard circuit is not confirmed by anyone