solid vs resistance grounding 4

[redraven6]

480, 3ph, 3 wire system supplied by generator. Should generator neutral be solid grounded or resistance grounded ? If resistance, how is resistor rating determined ?

 

[xxjohnh]

Low voltage generators are usually solidly grounded.Medium voltage generators are usually low resistance grounded or high resistance grounded if unit connected.

 

[dpc]

It's going to depend on the system being served by the generator and your tolerance for tracking down ground faults versus machine damage from ground faults.

Low resistance grounding at 480 V is not an option. High resistance grounding will greatly reduce damage from ground faults and reduce arc-flash exposure for workers.

Solid grounding is the most prevalent method in use now, but high resistance 480V grounding is gaining in approval, at least in the US.

 

[davidbeach]

If the generator directly (not through a transformer) supplies line-neutral load the generator must be solidly grounded.

 

[alehman]

If this is a backup generator, the grounding of the other source may influence your decision.

Alan
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"It’s always fun to do the impossible." - Walt Disney