How to measure current and AC voltage

Hello :) I want to know how to measure high current (about 15-20A) and a 230vAC voltage :)

I want to know how to measure high current (about 15-20A) and a 230vAC voltage

Very, very carefully. :)

you need a current transducer there are lots about look here:- http://uk.farnell.com/jsp/search/browse.jsp?N=1004254

Then for voltage you need first of all an isolation transformer, then you need to convert it into DC. What type of measurement do you want? RMS peak average? Most AC voltage is in RMS, so you need a true RMS converter:- http://uk.farnell.com/analog-devices/ad536akh/true-rms-to-dc-converter-ic/dp/2229195