Grounding/Ground Fault Electrical Questions

[Paul McNichol]

I am working on a project for a wastewater treatment plant where new process equipment is being added to an existing 2000 amp double ended MCC fed from two 1500KVA outdoor liquid filled transformers. The transformers are 4800V delta primary to 480V wye secondary. The neutrals associated with each transformer secondary were not brought to the MCC's as they were presumably not needed. The grounding electrode conductor to the transformer XO terminal and to the MCC ground bus is routed separately from a common ground loop that encircles both the building where the MCC's reside and the outdoor transformer pads outside of the building. There are no ground wires run with the secondary feeder conduits.

Question #1 Shouldn't there have been a separate ground wire run in each secondary feeder conduit?

Question #2 This service was installed in 2001 but without ground fault protection on either service. The way NEC 230.95 is worded it appears that only the exception regarding a non-orderly shut down would exempt the service from this requirement. That being the case is there something I am missing here? Wouldn't ground fault protection be required?

 

[ron]

Question #1 Shouldn't there have been a separate ground wire run in each secondary feeder conduit?

There needs to be some type of EGC brought to the MCC in / with each raceway (the transformers are not utility owned and the service is further upstream, right?). Is the raceway being used as the EGC?

Question #2 This service was installed in 2001 but without ground fault protection on either service. The way NEC 230.95 is worded it appears that only the exception regarding a non-orderly shut down would exempt the service from this requirement. That being the case is there something I am missing here? Wouldn't ground fault protection be required?

Where is the service disconnect per 230? Is it on the transformer primary or secondary?

 

[Paul McNichol]

There needs to be some type of EGC brought to the MCC in / with each raceway (the transformers are not utility owned and the service is further upstream, right?). Is the raceway being used as the EGC?


Where is the service disconnect per 230? Is it on the transformer primary or secondary?[1) The transformer is not utility owned. 2) The service disconnects in the process building from each transformer secondary is a 2000 amp main in each end of the double ended MCC. Each transformer primary is fed from a fused switch in primary switchgear also not utility owned]

 

[augie47]

I agree that without the grounded conductor being routed to the distribution you are in violation of the Code but if both the transformer and gear are properly bonded and both have a grounding conductor tied to a grounding grid you do, at least, have a ground path.
230.95 would not apply directly as this is not "service" gear. but it appears 240.13 would require such protection