Looking at your picture of your fuse box, your mains look easily accessible. Make sure the clamps go on the right way. I think I remember reading somewhere that there may be directional arrows that follow the flow of electricity, otherwise you may get some negative readings. Once you have it set up, I would recommend using this DTH (Device handler) by @johnconstantelo EDIT: Just discovered that the link to the code is broken in the thread below, do we have an updated link?