I don't think ESD is the right term, electro magnetic pulse is what I would (and have) called it. It might come from static electricity, but the magnetic pulse is what propagates the issue to another wire.

Where are, and what type are, your motors and drivers?

I had a CNT motion systems machine in the past, that developed an intermittent short on the spindle cooling fan... similar to switching a dust collector on and off but probably less power (maybe higher voltage, v220 if I recall).

However, it was only a problem because the fan wiring ran beside the step and direction single wires which needed to get to the gantry. After that point it went to closed loop servo drives (mounted to gantry) but with no feedback to the PC control.

The fan short would move one of the two Y axis motors in my case, eventually causing the system to fault from the torsion of one side of the gantry out of alignment.

Took years to figure out.

But, very hard to happen if you have closed loop motors and drivers in a cabinet, as my current Chinese router does. But, if I recall, your machine has a cabinet below the table. I would check the wiring BEFORE that cabinet first, although if the motors are open loop it probably could be after the cabinet......in that case I'd think about swapping in a closed loop stepper and driver which should be able to correct for such things, even if it was the dust collector.

Sent from my Nokia 3.4 using Tapatalk