Generator Grounding Electrode Conductor

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infinity

infinity

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I have a big diesel generator, 1750kw/2200kva and on it are 4 disconnect switches each with a factory bonded neutral. The there no bonded neutral in the generator compartment itself just in the disconnects. This will be an SDS so where would you land the GEC(s)?
 
It appears you need a system bonding jumper on the supply side of the disconnects and that you would connect the GEC at that same point.
 
don_resqcapt19 said:
It appears you need a system bonding jumper on the supply side of the disconnects and that you would connect the GEC at that same point.
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I thought about that, bring a single GEC into the cabinet, bond the neutral and land the GEC but then the factory bonded neutrals in the 4 disconnects would put neutral current on the metal parts of the generator. Here's the neutral compartment:

20181212_082402.jpg
 
It seems like you should be permitted to have multiple system bonding jumpers and GEC connections for the SDS. You can do that with services and multiple main bonding jumpers, but I don't see that same language for the SDS.
 
don_resqcapt19 said:
It seems like you should be permitted to have multiple system bonding jumpers and GEC connections for the SDS. You can do that with services and multiple main bonding jumpers, but I don't see that same language for the SDS.
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Good point. I was trying to avoid running a GEC to each disconnect but I 'm not seeing a way around it.
 
rlundsrud said:
I'm guessing the four disconnects don't have a spare pole so that you can switch the neutrals at those disconnects.
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What kind of branch does the generator serve (Emergency, Life Safety, Optional Standby?)

If optional standby, why not disconnect the neutral to ground bond from each disconnect? Pass the neutrals through the disconnects and transfer switch and create a 3-pole, solidly grounded system. All you would need is an EGC.
 
jeremy.zinkofsky said:
What kind of branch does the generator serve (Emergency, Life Safety, Optional Standby?)

If optional standby, why not disconnect the neutral to ground bond from each disconnect? Pass the neutrals through the disconnects and transfer switch and create a 3-pole, solidly grounded system. All you would need is an EGC.
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EM/Life safety. There are 4-pole ATS's so the system is designed as an SDS.
 
shortcircuit2 said:
Did you consult with the manufacturer about pulling the jumpers in the disconnects and installing the system bonding jumper inside that gen-set and then land the GEC there?
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No, we've been instructed to bring a separate GEC to each disconnect which seems like the only option without some field modification as you've suggested. I would prefer your method. :)
 
shortcircuit2 said:
Interesting arrangement. Thanks for sharing.
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You're welcome. This is the first time we're using a generator set up this way (with 4 separate switches), typically they have a switchboard with a single main and where we bond the neutral if not factory bonded and land a single GEC.
 
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