Electrical system bonding with different voltages

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Hi.
We are having problems with a grounding system. The building has four different voltage systems: 3ph 277Y/480V for new lathes and Mills; 3ph 277Y/480V for special equipment; 3ph 120/240V with high leg for old lathes and Mills and 3ph 120/240V for building's general services.
The thing is that some workers have reported little tickles when touching some of the machines (both 480V and 240V).

We found out a big grounding problem, only The special equipment 480V system seems to have a Solid grounding and bonding, not the case of the rest. The question is: can we Bond the different transformer banks into a unify grounding systems for detection and cleaning of ground faults?

Or What would be the best solucion in you opinion.

Kind Regards!
 

augie47

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Location
Tennessee
Occupation
State Electrical Inspector (Retired)
All of the services and separately derived systems should be properly grounded. 250.30(A)(6) discusses grounding of multiple systems to a common electrode.
 
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