In our machines Workpiece is nicely isolated by Spoilboard, V-Wheels etc. With a 3rd party machine, you would have to isolate it accordingly
As I said Dave, I've never had any probing problems, and still don't, either with plugged in laptops or my current desktop. I only use 3 pin earthed plugs. However, I don't use laptops anymore while I have a newly installed desktop. I was just trying to figure out why others have this problem. When I read this thread a week ago, I checked my probe ground pin on the UNO board and measured the resistance from that point to earth on the wall socket and got around 50 ohms. I get around the same reading from the USB connector shell on the UNO to wall socket earth. Wasn't sure that told me anything though, hence not posting about it.
