nerspellsner said:
... The manufactuer wants a ground rod installed next to the generator to ground the enclosure of the generator. This seems to present a problem because the service will be grounded at two seperate points because of the EGC bonding the two earth grounding locations together. Will this cause any problems or is this grounding configuration acceptable in this situation? ...
First ... your neutral is still only grounded (bonded) at ONE location ...
at the service. There might be multiple grounding electodes installed as part of the
grounding electrode system ... but the
neutral is still only "grounded/bonded" at one point so as to prevent parallel neutral paths.
What the manufacturer is apparently requiring you to install is a
supplementary grounding electrode (See 250.54). It shouldn't cause any problems ... although it's of dubious value because as you've correctly pointed out, the genset frame will already be fully grounded via your correctly-sized EGC. Note that the supplementary electrode is exempt from the #6 bonding jumper requirement usually associated when tying-together multiple grounding electrodes.
While it's already been posted, I'll repeat for emphasis ... what's IMPRORTANT is to ensure that the non-SDS genset's neutral is isolated from the genset's frame ... so that the service is still the
only neutral-to-ground bond point in the entire system.