After spending the last year building an extension I now find that I
cannot simply extend the groundfloor ring circuit as this also
incorporates the upstairs ring circuit. This area conveniently
measures 98 sq.m.
So a separate circuit is required. Of course the CU is on the opposite
side of the house. Running cable under the floorboards is
impracticable so here is my question.......
Is it acceptable to run 5m length T&E up the side of my house (into
the loft) if it forms part of the ring circuit?
On 6 Feb 2004 18:32:13 -0800, firstname.lastname@example.org (Ian) wrote:
I don't completely follow what you are suggesting.
Basically you want to run a separate circuit for the extension, so the
existing one is not really relevant to that, except that you are
saying that since it covers near to the maximum area you wouldn't
For the new circuit, you could run it as a ring circuit, and it is
perfectly reasonable to run the two cables required through some other
space using the normal rules of running cables - i.e. within 150mm of
corners or tops of walls etc. unless protected and grouping rules.
They can be run together until you reach the area and then go off in
different directions as you form the ring, or even run physically but
not electrically in parallel as long as a ring electrical layout is
When you say "run up the side of my house (into the loft)", if you
mean run outside the building in PVC T&E then the answer is no, it is
not suitable for outdoor use because UV from the sun breaks it down
eventually. It should be run inside the house.
An alternative, if the load is not expected to be significant, is to
run the circuit as a radial one using 2.5mm^2 T&E and a 20A breaker or
4mm^2 with a 32A one. However, since cable is cheap and you are
going to have to run one cable, you might as well run two, so I am not
sure that it makes sense to do this.
To email, substitute .nospam with .gl
Thanks for the reply. Sorry if my English was not clearly understood.
My house has a floor area of 96 sq.m. supplied from just one ring
circuit. So, as I understand, I am not allowed to go above 100 sq.m.
Hence the need for a new ring from the CU in the kitchen.
The easiest way to provide the power (20A and 6A, via new CU with
extra space for the mcb's) would be to run the cable through the
kitchen wall, up the outside of the house, across the loft, then into
the new extension.
The cable (2 x 2.5mm + 1 x 1.5mm) would be in 25mm conduit attatched
to the outside wall. Facing N.E.-ish, this wall receives virtually no
Is this allowed or do ring circuits have to be completely indoors?
Def-nit-lee a better idea, as Ed says. For us d-i-y'ers, HiTuf/SuperTuf
is easier to work with than SWA - it's a circular PVC cable with a
harder and UV-resistant outer sheath, and goes into CU boxes through
simple compression glands. CPC sell cut lengths by mail order, as will
most electrical counters (watch for the break-even point between buying
a cut length and a 50m roll).
HTH - Stefek
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