The wiring in my property uses the conduit as the earth. I've checked the earth resistance and have no problems there. Unfortunately some of the ceiling lights are not properly grounded as the tabs on the end of the fixing box have been snapped off at some point in the past. Without making a mess of the ceiling there is no way to replace the fixing box. This means there is no obvious way to join the light fitting ground to the conduit. Are there any tips on how to do this? I don't think soldering a wire onto the conduit pipe will work. Thanks.