My project, a CNC type machine has a Mean Well 24 VDC power supply. My Arduino runs off 5 volts, coming from a roboclaw motor controller. I have limit switches 15 feet out, on the head, which also has AC and DC motor wires running thru the same cable chain carrier. I was having trouble with my Y axis home limit switch being tripped occasionally, when energizing the motor out on the head. I swapped out my limit switch wire for a very good shielded 2 conductor cable. That fixed the problem, even without connecting the outer shield to anything. Then I went ahead and connected the shield wire to the ground wire inside it which would be the ground coming from the Arduino itself.
I'm wondering about the Arduino ground, and the earth ground, like the chassis of my CNC machine. Would it be best to connect the shielded jacket to the arduino ground, the earth ground, or both. I currently have the shielding connected to my arduino ground and if I read the voltage across it and the chassis I get like .3 volts. I think that just phantom voltage as if I put the grounds all together nothing adverse happens.
I'm just wondering what is the best of normal thing to do with the shielding jacket on low voltage wiring for microswitches on a CNC machine?