adding Fsu to a spur?

[adam81]

Hi, I have a spurred double socket that I wish to extend out from.

I realise that in reality you usually put the Fsu in then spur accordingly, however given I wish to keep the double socket in its current location can I spur off from this to an Fsu thus protecting the circuit from that point onwards?
Thanka

 

[333rocky333]

what rating is the fuse/mcb for the existing circuit.
If it was a ring the idea of the fcu would be be to stop sockets after the fcu from overloading the branch cable supplying the fcu, as you propose keeping a socket BEFORE the fcu, this defeats the objective of the fcu

 

[ban-all-sheds]

can I spur off from this to an Fsu thus protecting the circuit from that point onwards?

No.

 

[adam81]

I suspected as much. Currently its on a 32a mcb.

I realise the fcu is there to protect the sockets from this point on but in reality is it not the same?. The first socket is on 2.5mm cable and protected accordingly. Then the branch after that is protected by the 13a.

The only difference i see is the small bit of flex from socket to fcu but would that not be the fcu anyway?

I'll make the changes as per regs just interested is all.

 

[flameport]

The 2.5mm cable is not protected against overload. The 1st socket is permitted, as the maximum load is 2x13A, or 26A - approximately the maximum allowed for 2.5mm in the most favourable conditions.
Adding a 13A FCU after the socket would allow the cable to be overloaded.

Rings are only allowed with 2.5mm as there are 2 cables to each position, and it is assumed the load will be distributed reasonably evenly on the ring.

 

[adam81]

Right I see, it's the first spur cable that could potentially be overloaded to 39a. Failed to realise that.
Cheers

 

[JM2]

As an aside, *if* this was a spur with a single socket in situ, would an onwards FSU (and socket/s) be permitted then?

 

[flameport]

Decades ago it could be 1 double or 2 singles or 1 fixed appliance. Although 2 singles is electrically equivalent to 1 single and 1 FCU, that combination was not mentioned.

However only 1 double or 1 single is permitted now, for reasons not explained.

Also unexplained is why ring final circuits are still permitted at all, or why some people continue to install them.