I've been working on getting a CT sensor to work for a couple of weeks now. I've been doing my testing with a standard 13A kettle lead and have separated the live, neutral and earth - putting the clamp around the live wire. This has worked fine and I've got some accurate, calibrated readings.
However, when I put the clamp around the main incoming live wire to my house (in the consumer unit) I get readings that are 4 times what my testing has lead me to expect. Unfortunately it's not simply a case of dividing the figure by 4 as this doesn't work for readings below 250W. The return voltages from the CT sensor seem to have completed changed and the figures are useless. As far as I'm aware, the incoming cable is single phase and is a single cable therefore I shouldn't be seeing current duplication.
Has anyone had to deal with this before or could point me in the right direction?
Many thanks, James