new cu in extention

[supersead]

hello i am having a new extntion built a kitchen diner. the first fix has been done and a new cu is being installed in the extention. this is a 5 way cu which will be connected to the existing cu in the original house. i was wandering what wire is used to connect the 2 cu's up and does the wire need to be in any special conduit. the cable connecting up these will be run through the loft in a 5 metre run. any ideas would be great.
by the way i am not qualified and will not be doing the work just would like to know if the work is getting carried out correctly. thanks

 

[Lectrician]

A 5m run? I would expect the 5 new circuits to be run back to the original CU, and the original CU replaced if required. A submain is usually employed if a larger distance is envolved.

What is this CU feeding? I would think the best option would be a 16mm split concentric cable, fed by a 50 or 63 amp MCB. However, if the load is likely to be large and constant, it should be fed from a dedicated Switch Fuse.

It doesn't require any additional protection in the form of conduit.

 

[supersead]

the new extention is a kitchen diner with 9 downlighters 3 pendants with outside lights under a canopy as well as wall lights.
also all kitchen appliances including range cooker.
outside sockets/front and back and in the future suppling a conservatory as well and possibly a workshop.

 

[davy_owen_88]

For such a short distance why didn't he just run them back to the main CU? As first fix has already been completed it's a bit late now but I'm curious as to the reasoning behind it.

Have you told your electrician what the expected load is going to be? Has he told you what he intends to do or given you a quote?

Depending on various factors 10mm² cable is the least he 'should' use with 16mm² being preferred because of the possible load of a future workshop, kitchen circuit and cooker radial, so be concerned if he uses anything smaller unless he has a good reason and calculations to back it up.

Davy