thanks for your suggestions so far. All tests were done with no cabling connected. Each unit came with a two prong plug with no ground. I did replace the attached cords with a IEC receptacle. My concern is the high voltage on the chassis when the unit is switched off. On one unit, it measures 10 volts.
Measuring AC phase Question
I understand I am to reverse the plug in the AC outlet and measure from a known ground, in my case, a galvanized water pipe, and the positive probe is connected to the equipment chassis. I use a cheater plug on the power cord to allow reversing of the orientation. No other cords are connected to the equipment being tested.
You are supposed to choose the position of the cord that yields the lowest ac voltage on the chassis when the unit is on.
The problem I have is that the lowest voltage with the switch on also has by far higher voltage on the chassis when the power is switched off.
You are supposed to choose the position of the cord that yields the lowest ac voltage on the chassis when the unit is on.
The problem I have is that the lowest voltage with the switch on also has by far higher voltage on the chassis when the power is switched off.