Single Generator Power Distribution

Npstewart

Senior Member
I have two new construction smaller residential homes on a single site that the owner wants to backup using a single generator placed in between them. Normally when I feed two structures from a generator, its for a commercial project and I usually just call out for the generator to have two circuit breakers. However, being that this is more of a residential style generator, im not sure I have that option.

The generator they want to use is a Kohler (60RCL) which comes with a 250A circuit breaker. My plan was to set a MLO 400A rated panel (Panel GDP) next to the generator and then put a 150A circuit breaker and a 125A circuit breaker within that panel (one for each respective structure). The panel would be mounted on a concrete pedestal.

With respect to grounding, do I treat the pedestal like a separate structure? So I would have a GEC at the panel to driven ground rods, and then I would have an EGC routed with the feeder conductors to each respective SER ATS where I would then have an additional GEC? Then im assuming there would just be an EGC between the generator and the generator distribution panel (GDP?
 
I think a dwg showing the grounding/grounded conductors and the various bonds would help (at least I'm not picturing them).
Where are the service meters, disconnects, and SBJs?
Is the generator to be an SDS or not?

I suspect that co-locating the service point(s), meters, ATSs, and generator, then running feeders to each house, would simplify things.
 

synchro

Senior Member
Location
Chicago, IL
Occupation
EE
It sounds like it would be appropriate to have the generator be a SDS (with its neutral locally bonded to the EGC), and the ATS for each house would select either the neutral from its own service or from the generator when the power is transferred. Otherwise the service neutrals of the two houses would be tied in parallel by a common connection to the generator neutral, thus forming a large loop.
 

texie

Senior Member
Location
Fort Collins, Colorado
Occupation
Electrician, Contractor, Inspector
It sounds like it would be appropriate to have the generator be a SDS (with its neutral locally bonded to the EGC), and the ATS for each house would select either the neutral from its own service or from the generator when the power is transferred. Otherwise the service neutrals of the two houses would be tied in parallel by a common connection to the generator neutral, thus forming a large loop.
I agree. I think it could be argued that this is required.
 

Npstewart

Senior Member
It sounds like it would be appropriate to have the generator be a SDS (with its neutral locally bonded to the EGC), and the ATS for each house would select either the neutral from its own service or from the generator when the power is transferred. Otherwise the service neutrals of the two houses would be tied in parallel by a common connection to the generator neutral, thus forming a large loop.
So your’re thinking to use a 3-pole single phase transfer switch for each home? I’ll have to look into this to see if Kohler makes this.


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hillbilly1

Senior Member
Location
Atlanta,Ga
Occupation
Field coordinator/ technical support
How are they going to power the charger and block heater? (If equipped) Solar would not be feasible for the block heater, but would work for the charger.
 
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