Now that I have a milliohm meter, I want to measure the resistance of everything.
Ground quality is important for safety and signal quality. So I measured the resistance of my grounding network. I made two 5 meter long Kelvin probes to do so:
I have two main ground connections. One is the ground pin on a standard wall outlet. The second is a braided wire to a water pipe:
Normally these ground exits are star connected. As a test I disconnected them from one another and measured the resistance between them: 700mΩ.
For various test points on the machine and rack we see from 10 to 100mΩ
I realized that this potentiometer is not grounded at all!
I will ground this forthwith!