I have a current controlled power supply giving out 8 A (at least that's what I'm setting), plugged into a cable (call it #1) which is then connected via screws&crimps to a copper coil (call it #2, 70 turns, 1.25 mm diameter, 25.4 m length) to generate a magnetic field.
At the crimps, with a multimeter with a 10 A max fuse, I measure 3.8 A. I am using croc clips on the screws.
If I connect the ground of the multimeter to the '-' terminal of the power supply, the reading becomes 5.5 A.
Is it normal that the multimeter does not read exactly the correct current? Should I trust that current or the one displayed on the power supply?
P.S. = cable #1 is probably not rated for 8 A. But that should not affect the current right?
Image of test setup: