Another spur question...

[timmel]

I currently have just two sockets in the upstairs of my house - one in each of the two bedrooms, located back to back on the partition wall.

I'm looking to add more sockets as it's inconvenient as it currently is. Both sockets are currently feeding a spur to two downstairs sockets (one spurring from each upstairs socket) - presuming this was done by the previous owners.

My plan is to add a 13A FCU to each of the two existing upstairs sockets and feed this to a couple of new sockets in each of the bedrooms, then connect this back in to the downstairs socket that was originally spurred off.

So basically i'll have two sets of the same setup which is:
- FCU connected off from upstairs socket
- connected to first new double socket
- connection to second new double socket
- connection back down to original spurred socket downstairs

Connections will be made using 2.5mm2 cable.

Does anyone have any comments or suggestions on this?

I don't like the fact that my new sockets will have a cable in and a cable out, thereby potentially giving the impression that this could be part of the ring main, however with the 13A FCU it should be sufficiently protected.

Would welcome any thoughts or advice?

Thanks

 

[OwainDIYer]

Your total load would be limited to 13A which may be restrictive. Assuming that the two bedroom sockets are adjacent on the ring, can you not just extend the ring round the bedrooms and remove the short length of cable linking the two existing sockets together?

 

[ericmark]

Appendix 15

• ericmark
• 31 Aug 2009
• 5

Shows changes July 2008 Note 434.2.1 limits unfused spurs to 3 meters.

Diagram shows what is permitted. If original socket is replaced with a FCU you can then install as many sockets as you want from that unit. As the maximum current is 13A.

However consideration must be given to physical connections and if you intend to have a spur and a FCU then that is wrong.

Once a FCU is used any sockets after that point are part of a radial not a spur.

With so few sockets it sounds like a old house and I would advise that the earth loop impedance should be checked before adding and sockets where RCD protection is not included.

The problem is with a short circuit is something goes wrong you want the fuse to blow or MCB to trip. The ELI checks there is not too much cable as if there is too much instead of fuse blowing it will just heat up.

You may if your a new occupant have a copy of the periodic inspection report required on change of occupant if so that will say what the ELI is and then you will know if there will be a problem adding to the system.

 

[timmel]

Thanks for the replies so far. Maybe extending the ring main is the best all round solution. Is this generally acceptable with 2.5mm2 cable or is it better to 'beef this up' to be on the safe side?

In reality, 13A for each of the bedrooms would be more than enough (we never use elec heaters so the worst case would be hair dryer plus TV (and the downstairs spurs are only used for lamps)) and this would be protected anywhere if this current was to exceed 13A. But I suppose it's not much harder to extend the ring main which will obviously avoid this 13A limit.

 

[sparkwright]

What size fuse or circuit breaker protects this circuit that you intend to work on?

As mentioned, having so few sockets suggests it is an old installation, and may need a good checking over.

 

[timmel]

Will check the MCB rating when I get home, thinks it's 32A. The house is a 1960s dormer style semi (it was never a bungalow - was constructed as a two storey house) so two sockets in all of the upstairs is pretty stingy! The CU is about 12 years old.