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

 

[TaffyDuck]

Yea but it's fused with the 3a sfu??
Maybe you should look at the pics again. Neither picture is showing a spur that isn't fused

The spur is cable from the socket to the 1st SWCU and is unfused

 

[ipf]

The spur, ie the cable, is not fused. If it was, the fcu would have to be part of the ring. Then again ,we can all nit-pick.

 

[Snapester]

Taffy there is nothing wrong with the first one, have a look at Appendix 15 in the regs book page 425.
The light switch and boiler are both SFCU with 3amp fuse fitted according to the picture.

 

[TaffyDuck]

Taffy there is nothing wrong with the first one, have a look at Appendix 15 in the regs book page 425.
The light switch and boiler are both SFCU with 3amp fuse fitted according to the picture.

I am looking and its different, not saying 6 amps is going to do any harm. Look at the bottom of the diagram

 

[Lighting]

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.

 

[ezzzekiel]

Lost for words

 

[Snapester]

Sorry Taffy you lost me on that one i don't see any difference at all Appendix 15 shows spur protecting sockets? You dont need a FCU protecting a FCU where would it end?

 

[Guest55]

All this chatter for installing a couple of points , you'd think domestic work is complex reading all this lol.

 

[ipf]

Put a K with the FCU and then it it.

 

[mickys86]

The spur, ie the cable, is not fused. If it was, the fcu would have to be part of the ring. Then again ,we can all nit-pick.

Thanks for clearing that up always learning

Still nothing wrong with the first option thou!!

 

[ezzzekiel]

All this chatter for installing a couple of points , you'd think domestic work is complex reading all this lol.

Really makes you wonder what's going on out there!

 

[TaffyDuck]

Sorry Taffy you lost me on that one i don't see any difference at all Appendix 15 shows spur protecting sockets? You dont need a FCU protecting a FCU where would it end?

Ok, the part of the diagram on page 425 shows a spur off the ring main at 9 oclock. The 13A FCU is limiting the current that can flow through to 13A therefore protecting the cable. The OP diagram 1 shows a spur going straight to the first FCU and then on to another FCU. Therefore with 13A fuses put in each it is possible that the total draw could be 26 Amps thus overloading the cable. The 3 amp fuses fitted to the FCU`s are irrelevant as they are protecting the cable going out from the FCU to the appliance.

Now I appreciate that 6 amps, or the load from a boiler and a light (which is going to be less in all likleyhood) is not going to damage the supply cable however the light and the boiler are " fixed equipment" therefore the relevant part of the diagram is at 6 oclock where only 1 fixed item is allowed.

The reasoning for this reg IMHO is that should the fixed equipment be changed in the future, say an immersion for a boiler and a socket for the FCU running the light then you have an overloaded cable.

I refer to my previous post regarding fixed equipment on spurs.

 

[Guest55]

Really makes you wonder what's going on out there!

very little if it takes hours of debate to fit 2 fcu's :-D

 

[TaffyDuck]

very little if it takes hours of debate to fit 2 fcu's :-D

Ok we will all shut up until we can have a debate about something that you consider appropriate your highness.

 

[pencilpusher]

Ok, the part of the diagram on page 425 shows a spur off the ring main at 9 oclock. The 13A FCU is limiting the current that can flow through to 13A therefore protecting the cable. The OP diagram 1 shows a spur going straight to the first FCU and then on to another FCU. Therefore with 13A fuses put in each it is possible that the total draw could be 26 Amps thus overloading the cable. The 3 amp fuses fitted to the FCU`s are irrelevant as they are protecting the cable going out from the FCU to the appliance.

Now I appreciate that 6 amps, or the load from a boiler and a light (which is going to be less in all likleyhood) is not going to damage the supply cable however the light and the boiler are " fixed equipment" therefore the relevant part of the diagram is at 6 oclock where only 1 fixed item is allowed.

The reasoning for this reg IMHO is that should the fixed equipment be changed in the future, say an immersion for a boiler and a socket for the FCU running the light then you have an overloaded cable.

I refer to my previous post regarding fixed equipment on spurs.

I actually think this is an interesting debate and it has got me thinking TBH. I think Taffy is right here. The 13 amp FCU protects the whole of this spur cable in the future no matter what DIY Dan adds to it (and he will). The FCU's downstream could allow 26 amps to be pulled through and damage the spur cable upstream. Hmm