Hi,

Thanks for your replies.

The application is controlling a 3 phase welder with current feedback giving between 200 & 3000 amps. I already have a working product, but on some sites the welders act strangely. I eventually thought what are the 3 phase inputs refferenced to? So I am now thinking i need to connect the pcb's 0V line to Neutral or earth. Earth would be best since most 3ph supplies dont have a neutral connected in practice.

Bob...