I bought the Octopus TA17-03 non-invasive current sensor a while back. Now when trying it out I did not get it to work. I connected it to an Arduino Uno and used the EmonLib. No current at all were measured. I had not tinkered with electronics for a couple of years, I was a bit rusty. But after a bit of fiddling and discussion with friends I realized the problem. Of course you cannot run both wires through the sensor, only one. If running both Live and Neutral through it, then they cancel each other out, thus no current is registered.
So now it works. Still not calibrated, but at least I can detect if there is a current flowing or not. Let me know if you would like the sketch and diagram.