To spur or not to spur?.....

[Dave OCD]

There used to be [and still is I think] a picture in the OSG showing sockets via a FCU beig fed in 1.5mm. I wonder if anyone's ever done that ? In theory fine but I like 2.5 or sometimes 4mm in socket terminals.

 

[westward10]

I have spurred off a ring final in 1.5

 

[Dave OCD]

Maybe to a fixed load and not another socket ?

 

[westward10]

Fcu or a one gang socket.

 

[Dave OCD]

Fair enough, I do like a bit of 1.5 but normally stick to using it for larger lighting loads or a radial to a small NSH for example. Good for boiler supplies too.

 

[Martyn Fletcher]

I'm all ears (|oo|)

 

[littlespark]

So the majority think it should be both spurs off the load side of an SFCU? That was my initial thought.
The back box is 32mm, but below the surface of the plaster so maybe close to 40. Should be ok for 4 cables.
Sorry if I confused anyone with the set up. I'll draw a diagram next time

 

[DPG]

There used to be [and still is I think] a picture in the OSG showing sockets via a FCU beig fed in 1.5mm. I wonder if anyone's ever done that ? In theory fine but I like 2.5 or sometimes 4mm in socket terminals.

1.5mm T&E from load side of a 13A FCU to a 13A socket sounds OK to me.

 

[happysteve]

Here's a thought experiment:

Imagine there was another blank 1G box on the RFC, maybe 3 feet away from your first one. You'd presumably not have a problem having one unfused socket spur from each of these?

Now reduce the distance... a foot apart, still happy?

2x 1G back boxes adjacent to each other (with a part of the ring between them)... Still happy?

How short does the distance between spur points have to be before you become uncomfortable? An inch? You could fit both in the same back box.

What about a length of zero? Two spurs, off the same point on the RFC, using 32A (or higher) 4-hole connectors?

Just a thought experiment

 

[littlespark]

Um... I've done the job now. I put the existing spur on the feed side of the SFCU, and the new spur, in 1.5 to a double socket from the load side. Right or wrong, its done now and I cant see the difference from this, or a spur off the back of a single socket and running an extension lead from it.

 

[Pete999]

Um... I've done the job now. I put the existing spur on the feed side of the SFCU, and the new spur, in 1.5 to a double socket from the load side. Right or wrong, its done now and I cant see the difference from this, or a spur off the back of a single socket and running an extension lead from it.

You have fed the new spur from an existing spur directly no FCU and fed the twin socket from the load side of the FCU Right so far?so that will be 2 unfused spurs and the twin socket fused from the new FCU? I'm confused now, can you do a sketch of wht's been done?

 

[Pete999]

Um... I've done the job now. I put the existing spur on the feed side of the SFCU, and the new spur, in 1.5 to a double socket from the load side. Right or wrong, its done now and I cant see the difference from this, or a spur off the back of a single socket and running an extension lead from it.

You have fed the new spur from an existing spur directly no FCU and fed the twin socket from the load side of the FCU Right so far?so that will be 2 unfused spurs and the twin socket fused from the new FCU? I'm confused now, can you do a sketch of wht's been done?

Um... I've done the job now. I put the existing spur on the feed side of the SFCU, and the new spur, in 1.5 to a double socket from the load side. Right or wrong, its done now and I cant see the difference from this, or a spur off the back of a single socket and running an extension lead from it.

An extension lead is not fixed wiring.

 

[Pete999]

You have fed the new spur from an existing spur directly no FCU and fed the twin socket from the load side of the FCU Right so far?so that will be 2 unfused spurs and the twin socket fused from the new FCU? I'm confused now, can you do a sketch of wht's been done?

An extension lead is not fixed wiring.

Have you bothered to look at Appendix 15 of BS7671?

 

[DPG]

I think the confusion stems from him using the term 'spur' to mean FCU. Apologies to the OP if I'm wrong.

 

[Pete999]

y

I think the confusion stems from him using the term 'spur' to mean FCU. Apologies to the OP if I'm wrong.

The reason I asked the question and I to appologise if I have it wrong, but it sounds has though the OP has fed an FCU from an existing spur on the RFC, that to my mind is 2 spurs, what say you ?

 

[DPG]

Not sure Pete. You could be right though.

 

[littlespark]

Ok. lets look at the existing installation. At one time there was a single socket, on the RFC. Some time later, a double socket was installed along the wall a bit. This could have been a valid spur off the RFC, yes?
At the same time, or at a later time, the single socket was taken off and a blank plate was put in its place, the joint which made up the spur was then made from 30A connector behind the plate.

Here I come along and connect a SFCU to the conductors. At the moment it is no different to the spur off the back of the previous single socket.
I then run another cable from the LOAD side of the SFCU to 1 x double socket. This double socket, which is solely for TV equipment, is switched and fused.

The original RFC is in 2.5 singles. Original spur in 2.5 T&E. My new cable is 1.5mm T&E

I do not see this as a spur-from-a-spur

 

[Pete999]

Ok. lets look at the existing installation. At one time there was a single socket, on the RFC. Some time later, a double socket was installed along the wall a bit. This could have been a valid spur off the RFC, yes?
At the same time, or at a later time, the single socket was taken off and a blank plate was put in its place, the joint which made up the spur was then made from 30A connector behind the plate.

Here I come along and connect a SFCU to the conductors. At the moment it is no different to the spur off the back of the previous single socket.
I then run another cable from the LOAD side of the SFCU to 1 x double socket. This double socket, which is solely for TV equipment, is switched and fused.

The original RFC is in 2.5 singles. Original spur in 2.5 T&E. My new cable is 1.5mm T&E

I do not see this as a spur-from-a-spur

Your original post seemed to imply, that you spurred from the original spur, ie original spur on RFC, along you come and take another feed from that original spur, to the feed side of the FCU and from there on do whatever because you have it fused at the FCU.
I'll try and elaborate, have you taken the suPply to the FCU from a spur or directly from the RFC?

 

[littlespark]

Its directly off the RFC. Supply side of SFCU has 3 sets of conductors. Load side has 1.

Sorry for the confusion. English was never my strongest subject. - That's why I became an electrician.

 

[Toneyz]

Its directly off the RFC. Supply side of SFCU has 3 sets of conductors. Load side has 1.

Sorry for the confusion. English was never my strongest subject. - That's why I became an electrician.

I get what you have done unswitched fused spur from supply/feed terminals
1.5 fused spur from load terminals.