I am looking into adding an additional socket to a cupboard near the consumer unit. One of the 2 mains MCBs has 3 wires connected: - 2 wires feeding a ring main circuit for bedrooms and living room. I don't want to touch that. - A 3rd wire which feeds a socket in the cupboard with a 2nd socket spurred from that. Ideally I want to somehow add a 3rd socket to these 2. Is this classed as a radial in which case I could spur a 3rd socket from the 2nd one? Or is it a spur in which case I can't spur from an existing spur? Or can I add a junction box of a FCU in order to add the additional socket?