Generator supply 2 buildings with 2 services

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romeo

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I have a situation where a building owner wants to supply emergency power from a generator to 2 buildings. Each building has a utility supplies service.

The 2 transfer switches open the neutral, so the generator is a separately derived system. This installation will create a parallel situation on the service neutrals when the transfer switches are in the emergency position.

I am convinced that it is not a code complaint installation, but I can not find a code section that applies.
Any help would be appreciated.

P.S The transfer switches are of the manual type.

Thanks in advance
 
iwire

iwire

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Massachusetts
It sounds fine and it could be done with solid neutral transfer switches.

Considering you are using switched neutral switches I cannot imagine how you would have parallel neutrals.
 
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RUWired

Senior Member
Location
Pa.
romeo said:
This installation will create a parallel situation on the service neutrals when the transfer switches are in the emergency position.
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By having switched neutrals in each building transfer switch, the parallel path is broken in both emergency and normal operations. The main bonding jumper in each building is no longer common between the two buildings because of the neutral being switched.
Rick
 
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romeo

Senior Member
Generator supplying 2 buildings with 2 services.

Generator supplying 2 buildings with 2 services.

hurk27 said:
As long as the neutral is not bonded to the EGC at the generator then there is no parallel path, but then the neutral shouldnt be bonded at the generator anyways.
Click to expand...

Thank you for the response. In this case I believe the generator becomes a separately system and the neutral and EGC are bonded together at the generator or the first disconnecting means as required 250.30(A)(1)

Thanks to all who responded, I agree that using a transfer switch that opens the neutral as shown in EXHIBIT 250.12
2011 NEC handbook there is no path between the neutral of the two services.

When I was first asked about this installation the intent was to use transfer switches with solid neutrals.
My opinion was that it would create a path between the 2 service neutrals , IMO that would create a hazard.

As always I was able to get help here. Thanks to all of you.
 
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