I've been asked to design a 208/120V 3-phase off-grid system where there will be a primary generator that will power a building, but if it stops, a second generator is to kick on and take over. My first whack at the design is to use a 3-pole transfer switch and bond N & GND in the main panel on the building, after the ATS, and ensure that there are no N-GND bonding jumpers on either generator. But does this meet Code? Would it be better to have both generators N-GND bonded, and have a 4-pole ATS. The building main panel would not have N-GND bonded.
Off-grid dual generator with ATS grounding/bonding help
- Thread starter donw
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- Licensed Electrician
Unless there is ground fault protection involved there is no reason to switch the neutral.
rlundsrud
Senior Member
- Location
- chicago, il, USA
No, there wouldn't if you ensured the neutral wasn't bonded at the generators.
- Occupation
- Licensed Electrician
What two locations? You don't have any utility power so there is no service point. Pick a spot for the N GND bond, in the ATS or at the main panel, everywhere else the neutral is isolated.
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