Congratulations. Make a list of possible causes and check all of them one-by-one.
1. Could be because of overcurrent as you say. Try:
- to create overcurrent situation in different ways. For instance, starting the spindle with maximum rpm and moving Z and X axis (rapid) positioning at the same time
- the best is to make peak current measurements.
- to make situation of overcurrent a bit easier - reduce feed rate, reduce spindle rpm.
2. What I would start from. Did you moved the machine to another workshop?
If yes, then:
- check the level. double check. Triple check. I had in practice even saddle broken apart because of ( X ) guideways were twisted.
- check the load percentage of each axis in full stroke length. The load shouldn't exceed 11% without load in any conditions and should be continuous.
- wiring number one. If the mains cable cross-section is enough for your machine?
- wiring number two. If there is main transformer ( very big one ) ? Check and double check wiring of the transformer. I have seen in my practice reverse connected. It gives desired voltage and some people think it is correct. No. Input does not serve as output.
3. Check wiring of Controls power supply. Locate the exact place where the power is disconnected - this helps to understand the root cause.
If you suspect that X drive causes the current surge, do the experiment: move Z, run spindle, don't touch X. And opposite: Leave spindle and Z in peace, move X only.