TheScullster wrote:
Hi all

Please can someone advise best practice for the following:

Do you want 16th edn compliance, or making it work ok safely? Why?


1970s extended property with subject extension to rear
Extension adjoins both the house and garage with fuse box located in
garage
Currently the sockets in the extension are a radial spur from the
breaker
covering the upstairs main house ring main

if its from teh CU it could be put on its own breaker, although the
trip would have to be low current if its just 2.5mm. 2.5 radials are
not reg compliant afaik, but if MCBed at suitably low rating, and youve
not got all your lighting running off it, theyre safe and workable.


Similarly the extension lighting is a radial spur from the upstairs
lighting
feed

no problem with that.


My questions:

In an ideal world I suppose I would have a separate breaker covering
the
extension supplies, or have them form part of the existing downstairs
ring/lighting.
Is it a big no-no to power more than one circuit from a single
breaker?

More to the point I wouldnt put a 2.5 radial on a 30/32A mcb/fuse. Is
the 2.5 clipped direct, buried in thermal insulation, what? With that
info one can current rate it, thus know what fuse/mcb to put it on.
However its not gonna be reg compliant whatever you do with it, unless
you rewire it as a 2.5 ring or a 4mm radial.


There are currently 3 single sockets in the extension, so I presume
that the
power to this room should be converted into a ring whether it returns
to a
shared fuse or not?

In some cases you do need reg compliance, in some you dont. The regs
are mainly about safety, but not entirely. Theres nothing unsafe about
a 2.5mm radial circuit on a 16A breaker and RCD, but it might trip on
some heavy-startup loads, hence the need to not have all your lighting
on it.


There are currently no spare fuse ways in the CU so it would be an
expensive
upgrade for one room to provide individual protection for these two
supplies.

A split CU kit is only =A370, plus wiring it up, plus fixing the
inevitable problem circuits. Another 4 way Wylex fusebox is of course
much cheaper, if its that tight.

Any comments on IEE Regs compliance welcome

Do you need compliance in your case? Given what youve found though, I
would want to check the whole system over and see if any nastier bodges
have been done.


NT