Walked into a plant this afternoon, to quote some work, and I am still noticing guys installing CNC machines, lathes, and such with ground rods by the machines.
I know manufacturers "require" this but the NEC is still somewhat unclear.
Under some excemptions you can put a ground rod if you want but the EGC from the feeder must be tied to it. You can't connect the ground rod by itself to the equipment without that being tied to the service ground.
See where i am going, I hope...
I remove them when I find them, after checking that an EGC was installed.
As long as the equipment is grounded to the source as required by the NEC they can add as many 'extra pointless' (supplementary) rods at machine.
250.54 Supplementary Grounding Electrodes. Supplementary grounding electrodes shall be permitted to be connected to the equipment grounding conductors specified in 250.118 and shall not be required to comply with the electrode bonding requirements of 250.50 or 250.53(C) or the resistance requirements of 250.56, but the earth shall not be used as the sole equipment grounding conductor.
Notice that to the NEC Supplementary is entirely different than Supplemental
Bob Badger Construction & Maintenance Electrician Massachusetts