bob wrote:

I am in the process of replacing a pendant light with some downlights.
I believe I have a lighting circuit similar to 'Method 1' on this page
http://www.ultimatehandyman.co.uk/lighting_circuits.htm.

(b) I can see no visible junction boxes in the ceiling void so I don't
think it 'Method 3 - junction box wiring'.

The junction box could be quite a distance from the fitting, so it's
probably this method.

I have 3 diy books (Collins, B&Q, DK) and none of them seem to describe
this circuit. Does anyone know what it is called?

Don't worry about the method name. Different books use different names
anyway. :-)

Basically what I need to know is if I replace the rose with a 20A
junction box, do I connect similar colour cores from the downlights to
the circuit cable from the switch in a star topology i.e.

1 red/2 browns at 1 terminal (1 red back to the switch, 1 brown to
each downlight)
1 black/2 blues at 1 terminal (1 black back to the switch, 1 blue to
each downlight)
3 earths at 1 terminal (1 earth back to the switch, 1 earth to each
downlight)

Yes that's correct.

To be pedantic the existing red wire is your "switched live", the
black is the "supply neutral" and the earth is the "supply cpc" -
according to one book anyway. :-)

John
--
John White,
Electrical Contractor