I have worked on several projects recently that require the use of a standby generator for municipal waste water treatment plants and water pump stations. These generators are not used for any life safety functions but to provide an alternate power source for the majority water treatment plant loads. These loads are three wire loads (no neutral) and if left de-energized, would eventually cause a back-up in the infrastructure that provides untreated waste water to the treatment plant. Does the NEC requirement for ground fault protection on solidly grounded electric services also apply to solidly grounded generators that are rated 1000 amps or more and are greater than 150 volts to ground regardless of the load served? As a side note - most generator manufacturers do not provide ground fault protective features on the generator main breaker regardless of the rating. They will instead make "provisions" for ground fault tripping via the ground the fault alarm features associated with the generator. My take is that we are exempted from using ground fault protection by exception no. 1 to 230.95. This exception would also supersede FPN no. 3 to this section.
Ground Fault Protection for Generators
- Thread starter mcnichol
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Bea said:
But this sounds more like a 702 application of the generator, so 701 would not apply.
And for the record, 215.10 is the section that would apply, instead of 230.95. But I'm not sure your application meets the exception.
One other way to avoid the GFP might be to tap off the generator main breaker with 800A feeders to individual 800A breakers. (Assuming the load can be broken down into separate chunks.) Of course, you would have to also comply with the tap rules in 240.
Steve
wanderer20001us
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See 700.26 and 700.7 (D). GFP not required, only GF alarm.
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