On the clamp ammeters- I've found that with the cheap ones the shielding against anything outside the clamp is almost nonexistant. I've had some truely interesting readings from them if other stuff was close. (depending on the range of the meter sometimes as much as 15A off )

AlpineRAM

 

Alpine is not your system a bit different? In the '60s it was a two wire direct ground system at what, 240? I remember if you reversed the plug on Ameican stuff, you got knocked on your can.