Extra wire for security light

[Terry2sheds]

If it doesn't work when wired up in this way, even when the switched is switched in either direction then you probably need to substitute the additional black wire for either the black or red from the 3 core wire.
Try both combinations and using the switch with each combination until it works.

 

[electronicsuk]

Have you tried using the extra black wire as Neutral, and terminating the black that's part of the twin+earth cable into a small, isolated piece of terminal block? The remaining red as live, and the bare copper core sheathed with green/yellow and connected to the Earth terminal.

When you wired the light straight into the twin+earth without the additional black core, what happened when operating the switch in the kitchen?

Also agree with the comments above, connecting wires in various configurations is not a good method of fault finding. However, as there aren't that many different configurations with the number of wires you have, it's going to work sooner or later, assuming it used to work before fitting this new light.

 

[riveralt]

Heather, you should check the manufacturers instructions.

Firstly, most outside lights require the light to be connected via a (switched) fused connection unit normally fused down to 3amps. Its possible this can be done at the switch you are currently using.

What do the instructions say about the connections at the light itself - i.e. line/live or switched live, neutral and/or earth?

From what you said you have a T&E (red and black and earth) cable and another black cable at the light but what do you have at the switch and how are they wired?