Hi guys and gals, over the last 35ys I have 'wired' up lights and sockets on patio, shed and greenhouse in my back garden. Most of the diy/bodge wiring has recently been upgraded to meet current standards. But I still need to relace a feed to greenhouse that is just ordinary cable in a hose pipe (seemed a good idea at the time). I have just sourced 25m of armoured but it only has a red and black inside..Can I use the outer armoured as a earth?