How can a technician know if a piece of equipment before plugging it into the wall that the hot and neutral wires have been reversed internal inside the equipment. Some test fixtures or test equipment has either their hot and neutral wires reversed, no safety chassis ground or the ground is above zero volts. I have to take a fluke volts meter and measure the DC and AC voltage from ground of one test fixture or test equipment and measure the voltage difference against the ground or chassis ground of another test equipment. I measure the AC and DC voltage difference from ground to ground and chassis to chassis. The oscilloscope will short out when probing test point on a circuit board or on a test fixture test points. Why it shorts out is because it can be either of these problems.
The circuit under test Hot and Neutral wires are reversed
The circuit under test has no Safety ground
The circuit under tests grounds are above ground
I know if I use an isolating transformer this will solve all these problems, but how can a technician measure before plugging it into the wall if the circuit under test, test fixture or piece of equipment has any of these issues.
The circuit under test Hot and Neutral wires are reversed
The circuit under test has no Safety ground
The circuit under tests grounds are above ground
I know if I use an isolating transformer this will solve all these problems, but how can a technician measure before plugging it into the wall if the circuit under test, test fixture or piece of equipment has any of these issues.