Never mind, Doug Malone didn’t tell me the whole story. The current and voltage standards can be used at the same as long two different instruments are reading them. The two standards are not only isolated they are opposite polarity with respect to each other. So I will move on and use an AC resistive load to check out the power functions with different current clamps. I have a load bank with a very good power meter on it to compare it to. That will have to do for a standard.