Big Katuna wrote:
Measure the voltages as well. Might be a result of voltage drop.
The current reduces as the voltage goes down on a resistive load while it increases on a dynamic load like a motor.
While that's true for a changing voltage at the load (and the part about dynamic loads does depend on the specific load), it's not true about different points in the same circuit. The current that flows through a loop is constant everywhere throughout the loop; it doesn't go up or down as a result of various resistances (causing voltage drops) around the loop.
The correct explanation here is indeed given by old biscuit, and is likely exacerbated by the rather strange (non-sinusoidal) current waveforms some common loads create—most notably in this case many converters.
I find that my 30A EMS seems to read too high for the current, particularly for things such as the converter with poor power factors and choppy current waveforms. It's closer to accurate for nice resistive loads. (With a resolution of 1A, it's never going to be particularly accurate for a 30A maximum load—that's a 3% quantization error, even assuming absolute perfection otherwise. For a rough gauge on how heavily one's loading the line, it's sufficient.)
