Generator Transfer Switches

[little george]

If I have a generator installed as a backup for a utility and I have a need for backup for my house and my neighbors house- Can this be done legally per NFPA70? Issues I see would be the transfer switches for each house and possibly a confusing bonding issue. Let's say I own my house where the generator is located and I also own the neighboring house which I rent out to him.

 

[360Youth]

Each would have to have it's own TS. You may want to see if the neutral would have to be switched. That would be my approach, but I can not point you to code reference to say so. POCO requirements may have something to say about it. The other issue would be voltage sensing. Some is done at the genset and some is done at the ATS (assuming you you are doing this automaticly. n/a if manual configuration.) Depending on how the system receives it's signal to start, run, and transfer, you could theoretically end up with a generator that will only run if both services lose power if you do not plan it all out.

 

[tom baker]

A generator is a two wire start. You would need a voltage sensing relay at each house to send a signal to start.
You'll want to look at Art 225 for feeders and the disconnect requirements, its tricky as the locations are not under one management.

 

[RUWired]

Issues I see would be the transfer switches for each house and possibly a confusing bonding issue. .

You would need a transfer switch for each residence and atleast one of the transfer switches would need to switch the neutral to keep the grounds from carrying current.It would be best if both transfer switches switched the neutral to keep the fault current path directed to the gen set while running.
Rick

 

[benaround]

george, unless the generator is sized large enough to carry the loads of

both homes, manual transfer switches would need to be used. 702.5 (2005 NEC)

 

[LarryFine]

A generator is a two wire start. You would need a voltage sensing relay at each house to send a signal to start.

This could get complicated. Do they share one transformer?

If only one house loses power, should both houses switch to generator?