We have been insulating a roof space and needed to extend the lighting cable so that it drops beneath the extra insulation and plasterboard. The original cabling was grey with 3 wires - after speaking to someone at B&Q they recommended extending the cable with "0.5mm 2 wire" - which we have done using a connector. The earth which we thought we didn't need is screwed into connecting block and taped with insulating tape. Plasterboard is now up and covering the wiring. (Being skimmed tomorrow) The fuse box keeps tripping - i'd be grateful for any ideas on cause??? Thanks very much