l had to change my security light as it did not work and so l bought one similar. Anyway l switched the mains off and took of the terminal at the back of the one l was removing and it had 4 wires, a red live, blue neutral, earth, and a yellow..connected. Can someone tell me what the yellow was connected for. The new security light only had terminals for a live red, blue neutral, and earth, no extra terminal for connecting the yellow. So l connected the red blue and earth and capped off the yellow and it works fine so what was the need of a yellow. l trace the cable back in the loft and it went to a junction box with 2 other 4 core cables.