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Generator Grounding

Generator Grounding

Generator Grounding

(OP)
Two existing generators feed a 3W MCC equipped with an NGR via a transfer switch. The two gens are now being connected to a 4W sync board. The sync board will new feed the existing 3W MCC and a new MCC that is also a 3W.
Questions:
1.Is there any issue with the exiting configuration – 4W ATS (All breakers from gen to ATS are 3 pole) feeding a 3W MCC with a 2A NGR?
2.If the ATS is changed to a 4W sync bus so two or more gens are in parallel, can the new MCC be installed with an NGR similar to the existing and have the NGRs connected to the neutral of the common Sync bus?
3.Best solution in my mind to have an NGR at each of the gens and using the 4W sync bus as a 3W. Any issue with this?

RE: Generator Grounding

If I well understood the existing generators –no neutral provided-remain on operation-still without any neutral accessible. Why then the system does turn to 4W ?If an artificial neutral-zig-zag grounding transformer with NGR is intended to be provided ,for instance, then the actual NGR, it seems to me ,it will not be suitable.

RE: Generator Grounding

If there are any line to neutral loads, then the neutral must be solidly grounded. The only exception is devices intended to detect ground fault which may be connected line to ground or line to neutral (or neutral to ground).
I prefer (and the Canadian Electrical Code recommends) that the neutrals be interconnected solidly and not be switched in the transfer switch. Then only one solid ground or NGR on the entire system. There are instances where neutral conductors must be switched. Many of these cases could be avoided. Issues may arise when adding equipment to existing installations with ground current monitoring equipment. Most new installations and many existing installations may be installed without switching the neutral by the exercise of ingenuity.

Bill
--------------------
"Why not the best?"
Jimmy Carter

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