We're doing a bit of DIY in a house 300 years old - the problem is that we have a ring main (with the old cabling colours of red, black and no colour) and would like to add another light to the same switch as an existing light fitting.
When we have tried to use connectors (and electric cable to extend) to add the new light to the ring main, the existing light is either dim or doesn't turn on/off. At the same time, the new light is either dim or doesn't turn on/off.
How do we introduce the new light to the ring main so that new and existing lights are turning off and on when we want them to? And also, that the lights are not dim when turned on?